Strange suction in toilet and sink, like a vacuum in the sewer pulling the water out This is hard to explain.. But I was sitting in my bedroom when all of a sudden my toilet started draining, then the sinks in the bathroom started pulling air in, then when the water from the toilet drained, it started suctioning air down the toilet too.  It all lasted about 20 to 30 seconds.  This apparently happened a couple of weeks ago as well according to my wife.
This only happens in our new addition to the house, which has a partially separate line to the sewer (it joins up to the main line about 15 feet in front of the house).  I didn't see any sign that it affected other parts of the house on the original waste water line.
My only guess is that the suction is coming from all of the water in the line draining into the sewer at once, pulling air with it until the sewer line is open to the air.
We have a tub, a toilet, a shower and two sinks on this line and none of them were in use at the time.  I was seriously considering that someone was working on the sewer line outside with a vacuum or something.  Any ideas what might be happening here?
UPDATED WITH PHOTOS:
Here you can see multiple vent pipes.  I snaked both the close one and the far one.  Time will tell if it worked

Even if someone was "working on the sewer lines with a vacuum" properly sized and functional vents would keep the traps from siphoning.
So, you have vents which are not functioning as they should, whether from being built improperly in the "new addition" (since the problem is limited to there) or from some sort of blockage (animal nest in the vent pipe or the like.)
You, or, if that's not your thing, someone you hire should get up on the roof and check the vent pipe there, perhaps with a snake in hand to try cleaning it. Dumping a bucket of water down, or running water from a hose down can also sometimes be helpful in identifying a blockage (and can sometimes help to clear it.)
After that you (or someone you hire if it's not your thing) would get to checking and using all the cleanouts down inside the house, if the problem persists. For a typical venting setup with a single toilet, the fact that the toilet is affected points to the main vent (for this section of the house) being blocked, not just some tributary branch vent.


Front House Posts Not Resting on Anything I have 5 roof support posts that are supposed to be resting on concrete blocks but one of them is not even touching the concrete block and the other 4 have some separation from the concrete block.  See pics for details.  Seems like the ground has settled or something has happened to the house structure causing this separation.  I'm not sure what to do about this.  Does anyone have advice?  On what I should do to solve this problem?  Thanks for any help!

First Post Not resting on anything

Other Posts in order of 2 - 5 and how they are sitting on concrete blocks. Notice separations.

Here's another picture showing how the posts are used.

What you need to do is get a couple of hours of a residential truss engineers time.

Ask him if the posts are designed, or should be structural load bearing components of the frame, or just look pretty?

If they are supposed to hold up your house, below frost line footings and fiberglass posts are in your future.

If they are just to be pretty, then shims and hydraulic cement are all you need, and then replace with fiberglass pieces as time and money allow.

Fiberglass posts, columns are great, lightweight, any shape you want, load bearing or not, stay straight, no rot, no bugs, take paint so well.


What is the easiest way to replace an existing backsplash? I've got an unusual backsplash in my kitchen that I would like to replace.

As you can see from the picture, there's about 6" of granite tile acting as a proper backsplash, but above that it appears they installed sheetrock (flush with the surface of the tile) all the way up to the bottom of the cabinets.  So the combination of the tile and the sheetrock is like an additional layer on top of the actual kitchen wall.

I guess the point of this is to give the impression that the tile backsplash is embedded into the wall?  In any case, I would like to replace the backsplash with the least amount of work practical.

If it were just sheetrock, I assume I could just tile over it.  If it was just tile along the bottom edge, I would remove it first.  But the combination of the tile and flush sheetrock is complicating my path forward.

Am I going to have to remove the tile and the "false wall" above it? Or can I just apply the new backsplash right over the top of it?

There's close to 30 linear feet of this stuff, so removing it will be a lot of work I don't want to do if I don't absolutely have to.

Look on the right side of your picture.  You can tell the granite and fake stucco finish is layered on the drywall.

First you will not get drywall or backboard to adhere permanently to granite so it has to go or you have to use it.

Personally I would keep the granite.  Then I would scrape off all of the stucco.  It might sound like a pain in the ass but its not a HUGE project - 3 or 4 hours.  Then you might have to do some minor repairs to it.  If anything I would just take this stuff off in chunks and skimcoat the area afterwards.

You don't need backerboard unless you want to put up a heavier stone.  Drywall is fine.  Just scratch it up good before hand.  Throw down some tile that fits in with the granite.  I would use thinset instead of mastic so that I can level out any wall issues as I go.

If you keep the stucco and put something over it you are going to have some really odd edges and it just won't look right.


Wiring of Combination Switch and Outlet I just purchased a Leviton Combination Switch and Outlet and I wish to have the switch actually control that outlet.  I wired it to the switch end without breaking any of the tabs, and the outlet is understandably hot all the time.  Must I change the wiring configuration and remove the break off tabs?

These combination switch and outlet devices typically have four screws:

1 silver screw connected to the neutral side of outlet
1 brass screw connected to one side of the switch
2 dark screws: one is connected to the hot side of the outlet, the other connected to one side of the switch.  There is a removable tab that connects the two dark screws together.

The silver screw needs to be connected to the neutral (white) wire.

Leaving the tab in place, you have two ways to connect the hot (black) wire:

To have the outlet controlled by the switch, connect the hot (black) wire to the brass screw.  The dark screws then become a switched hot that you can use to control another device.
To have the outlet always on, connect the hot (black) wire to one of the dark screws.  The brass screw is now a switched hot for controlling another device.

If the tab is removed, then your switch and outlet are disconnected from each other.  Wire them as separate devices.  If you want to control the outlet with the switch, you'll need to run a wire from the switched side of the switch to the hot side of the outlet.


How can I tell if a ceiling box will support a real light fixture? I removed a fluorescent light fixture from kitchen but I'm not sure the work box will support a real light fixture. The work box is round and plastic. The fluorescent light wasn't even held up by the work box, it was attached directly to the ceiling.

I've installed light fixtures before to metal work boxes and its usually replacing another light fixture attached to the work box, so I know they can handle it. For this one I'm just not sure.

Here are pictures of the work box in question:

All ceiling boxes are required to support at least 50 pounds (NEC 314.27(A)), so you can assume the box will be able to support a simple light fixture.  Boxes that are designed to support ceiling fans must be labeled as such, and must have a label listing the weight it can support if over 35 pounds (NEC 314.27(D)).
If you look at the box you have, you'll notice a flat bit within the box.

This is designed to sit against a framing member, so the box is likely attached to the member with nails.  Your box probably looks something like this...

As others have mentioned, the holes in the back of the box can be used to attach the box to a support.  In your box you'll notice these holes are empty, which means the box is not attached to a bracket.

tl;dr
This box should have no trouble supporting a normal light fixture, up to about 50 pounds. It should not be used to support a ceiling fan.


What would cause arcing between equipment connected to each other where power is connected to different circuits? Scenario

In my "datacenter" (read: basement), I've got a rack of various computer and A/V equipment plugged into a UPS, and into a standard 120v outlet on one side of the room. This equipment works normally, and the UPS detects no wiring faults.

On the other side of the room, is another rack of equipment, going into a UPS, going into another standard 120v outlet.

All equipment is directly connected to either the outlet for testing or to the UPS.

Basically, imagine one side of this room as a mirror image of the other side.

Each outlet is connected to a different circuit.

The problem

Attempting to connect equipment using one circuit to equipment using the other circuit (say, a monitor plugged into circuit 1 to a PC plugged into circuit 2) results in a rather sizeable arc and burn marks where the cable touched the port. The lights dim, and the circuit breaker for one side or the other will trip if left for too long.

I have eliminated the equipment as a cause. All gear works fine whether plugged into one circuit or the other. The light show only happens when you try to connect devices that reside on different circuits. (With the exception of networking gear - I can connect computers on circuit 1 to routers on circuit 2 via ethernet with no problems).

The UPSes are also not the cause - the same thing happens when the equipment is plugged in directly.

Basic probing with a multimeter indicates that the outlets are operating properly and have working grounds.

A regular 3 light receptacle tester also shows that both outlets are wired "correctly".

What the heck is going on here, how do I test for it, and most importantly, how do I fix it without burning the place down?

That is very bad.  I recommend a comprehensive survey of the relevant parts of the electrical system, starting at your main panel.

Service grounding (earthing) system

This goes from a water pipe, ground rods, etc. to your main service panel.  If you have a sub-panel, it goes to the main panel.  It is the reference to zero voltage for the entire system. This goes to the ground in your panel.

Don't worry too much if it's not perfect, I'm more concerned with its relationship with the rest of your panel(s).

Ground-neutral bond in your main panel

Throughout the world, mains power is wired as if it's an isolated system with a grounded safety shield.  That is to say, ground is never used in any way to carry current, except during a fault condition.  But it is not an isolated system: to prevent wild voltages, neutral is intentionally bonded to ground in the main panel only, via a wire, strap or green screw in the neutral bus.

Make sure that exists and looks OK.  Without it, a ground fault in equipment will "electrify your grounds".  (actually put neutral at a wild voltage compared to ground.)

In the main panel only, it is legal to simply use one bus for all neutrals and grounds.  It looks awful; it makes you think neutral and ground are redundant; they're not!

Any sub-panels

If these branch circuits are fed from a panel, which is itself fed from a breaker off the main panel, make sure the feeder has a separate white or gray neutral and green/bare ground wire.  Metal conduit can substitute for a ground wire.  Make sure the sub-panel has a neutral bus and a ground bus, carefully separated and not bonded.

Also in the panel

Watch out for a ground bus with wires that are not green or bare.  Watch out for a neutral bus with wires that are not white or gray.

Now look for circuit breakers which have white, gray, green or bare wires going to them.  White/gray to a breaker is OK under a few circumstances:

a 2-pole breaker (the breaker itself is double normal width, and obviously has 2 handles tied together), often has 1 black and 1 white
A GFCI/AFCI breaker, which has 1 hot and 2 neutrals going to it (one coiled up and going to the neutral bus).

Obviously, pay special attention to your difficult circuits.

Now follow the receptacle chain back to the panel

For each circuit in turn...  Unplug everything and turn off one of the breakers.  Use a nightlight, circuit tester, plain lamp and some intuition to identify which receptacles and other loads are on that circuit.

Physically check: Now, work forward from the panel to your problem location.  Open up each junction box, remove the switches/receptacles from the boxes,  and give it  the basic eyeball.   I bet you'll find problems at one of them.

Electrically check: Voltage testers are hokey and don't work, because they are only comparing the receptacle to itself.   Noting that you started on electronics.se and know a thing or two, you can electrically test by running a wire back to that original zero reference.  The zero reference won't harm you, but getting between it and a hot voltage could, so I'd add a 20k-50k ohm resistor on the far end of it.

Voltage to ground should be <0.1 volts, essentially 0.
Voltage to the taller neutral slot should be 0 to 3 volts depending on load on the circuit
Voltage to the shorter "hot" slot should be near 120 volts
If you add a ~1500W heavy load on the circuit, neutral should increase, and ground shouldn't.

This is no substitute for a physical inspection.  You can't reliably detect a bootleg ground or ground-neutral swap, for instance, which are things which would cause this.

I guarantee you'll find a problem before you're done.  Possibly 2 or more, since a guy who makes a mistake often repeats it.


How much pressure fluctuation is normal on 3/4" line when one tap is open? We have a 3/4" meter / water supply line to our house.  How much pressure difference should I expect between when no water is running and (say) one cold tap is open full?  I assume flow rate is about 1gpm.

The reason I ask is that our pressure regulator was replaced recently, but we are still seeing noticable pressure drops.  Input pressure is close to 100psi (I haven't measure it exactly) so I would expect that setting it to 60psi there should be enough source pressure to sustain a fairly constant 60psi even with some water running.  How far below 60psi should I expect to see?

There are too many variables involved; it isn't really feasible to give a specific answer. You can determine an answer for your situation by determining the main supply line pipe material and length, checking for excessive quantities of elbows (ie more than just a couple), and then consulting a pressure loss table. For example, The Engineering Toolbox web site has such tables for SCH 40 PVC and Types K, L, and M copper tubing. Similar tables may be found for PEX, IPS- or CTS-sized HDPE, and other tube materials.

In all honesty, though, you can probably do well enough using one of the copper tubing tables even if your supply line is another material. For example, Engineering Toolbox provides a chart for Type K copper. The purple line 5th from the left is for 3/4" size. Choosing an arbitrary point on the line we see that expected pressure loss is about 0.1 psi/ft at 9 GPM flow. If you had a 100 foot supply line we'd expect 10 psi loss with 9 GPM flow. A static pressure of 100 psi and a loss of 10 psi while flowing should provide plenty of pressure left over for the regulator to be able to maintain a setpoint of 60 psi inside the house.

If that's not the case, the first thing you could do to investigate is to install pressure gauges before and after the regulator. You'll be able to see the static and dynamic pressures on both sides of the regulator and immediately determine whether you have excessive pressure drop in the supply, across the regulator, or possibly in downstream plumbing in the house.

In theory a regulator should hold its output steady through any fluctuations in flow or in supply pressure. In practice it won't be perfect. Sudden changes in flow will cause the regulator output pressure to overshoot or undershoot a bit (maybe a few psi I'd guess), and higher steady flow may also cause the regulator output pressure to run a little low. Each regulator is rated for a specific amount of flow; below this limit it should regulate fairly well. In all cases if the supply pressure drops too near to the output setting, or even falls below it, then all regulation is lost and the output pressure becomes equal to the input minus some semi-constant amount.


Does water based polyurethane affect the color of paint? I recently painted a dresser. I originally painted it a darker gray than I wanted so after putting the initial two coats on I took the paint back to Home Depot and had them lighten the rest of the gallon for me. The paint was not tacky at this point in the process. After applying the additional two coats the finish product is tacky. I'm pretty sure my mistake was too thick of an application on the last two coats. I thought the sheen was better with thicker coats...

Now that it is tacky I'm considering applying a water based polyurethane to help with the tackiness and give additional protection.

I'm just concerned with the polyurethane affecting the color of the dresser. What experience have you had with water based polyurethane over paint?

You should give those last two coats of paint a good long while to see if it will get less tacky and "cure".

If it stays tacky I would not try to fix it by trying to plaster an incompatible product like polyurethane on top of the latex paint. This would be an especially big issue if the base paint was not fully cured and dried. In this case the best order of business is probably to buy a gallon or two of paint stripper and remove all the paint on that item and start over with the color that you want.

Note: Also be aware that when you had the paint store remix your paint color it is possible that the amount of colorant that was added exceeded the manufacturer recommended amount of colorant volume per gallon and that changed the characteristics of your paint.


2-wire switch loop controlling 2 outlets - replacing with 3-wire to fix? I am in nearly this exact situation:

Can I use a switch loop to power a ceiling fan?

We are trying to install a fan, but instead of having a single duplex outlet on the same wall as the switch, we have 2 different duplex outlets on opposite sides of the room behind plaster walls.

This is the first time I've ever worked with a switch loop, and honestly, my brain is failing me. Can I replace the 14/2 romex between the closest outlet and the switch with 14/3, which should give me all of the conductors necessary to hook up the fan switch and fan? Or do I need to replace the wire between the two duplex outlets as well (as I said, the switch controls both of them)?

The first is probably something I can do with a spare saturday, a fish tape, and a 25' piece of 14/3. The second would require tearing down plaster through a good part of my wife's studio and more patching than I think we're really able to do right now.

Any help would be very much appreciated. Now I'm aware that several rooms in our house seem to be wired this way, and I'm thinking I have a mess on my hands. Especially because it doesn't look like any of the white wires have been marked as hot.

Edit due to confusion:

This diagram shows approximately how the wiring looks. The major differences would be, instead of having a lamp, there are 2 outlets. Both outlets are switched. Switch goes on, both outlets get power. Switch goes off, both outlets lose power.

What I believe I need to do is rewire the outlets and switch so they match this diagram which follows modern code:

These wiring diagrams belong to do-it-yourself-help.com. The original images can be found here: https://www.do-it-yourself-help.com/wiring_switches.html

What I need to know is if I have to include both of the outlets if I replace the 14-2 wire with 14-3? Can you install 14-3 half way through the switch loop?

The reference to a switch loop in the related question describes a pair of wires that are both hot or live. The white wire is serving as a black and should have a black marking or tape on it. The switch is serving as a break in the hot line.

Every operating device (like a fan or lamp) in standard wiring needs a hot line and a neutral line, and usually a ground, although that is not strictly necessary in all circumstances. In the wiring described in the other question, there was no neutral running through the switch box, but there had to be a neutral connected to the device itself, in the box that the fixture was attached to. The neutral wire is never switched, so only the hot lead was routed to the switch loop. Modern code requires that new switch circuits also have a neutral present, since some newer switch devices need a neutral to function.

Your situation may be different. On your circuit, one of the three boxes is closest (electrically) to the main panel. There is a live circuit line running either to one of the outlets or to the switch box. In either case the outlets you describe must have a neutral wire present as well as a hot wire.

If you want the fan to be switched on and off by the same switch as the outlets, you can simply add a wire from either outlet box to the fan location and connect all wires in parallel (black/white/ground).

If you want a separate switch for the fan, you need to tap into the power where the live circuit comes in to the room. It may be either of the outlets or it may be the switch box (if there is a neutral in that box). You need to tap into the unswitched hot, run that hot to a new switch and connect the neutral and ground in parallel. Then run the full cable from the new switch to the fan.

If you want to use separate hard wired switches for fan and light, run 14/3 from a switch box fed by the always hot line, using the two hots separately for the two features.

An alternative if you want separate switching is to run a full cable (14/2 or 12/2) directly to the fan from the box that has an unswitched hot. Use a fan that has a hand-held or wall mounted remote and wire the fan as always hot (no line switch). Then the remote controls whether power is going to the fan. This also simplifies installing a fan/light combination.

As to your other outlets, white wires are generally not hot unless used to connect to switches and should be so marked. Most white wires are neutral. You can test your outlets for correct wiring with a plug-in tester like this one.
.

If the tester reveals miswiring, you should consider calling in a pro. It also sounds as if you are not too familiar with wiring in general, so you may want to enlist the help of someone with a bit more experience until you become more confident. In any event be sure to turn of the circuit breakers before opening any box and confirm wire are not live with a non-contact tester like this one

 images and links are for illustration only, and not an endorsement of goods or sources


AC Capacitor Or Another Problem? (And What Type Of Capacitor?) I'm wondering if anyone can help me identify the issue here:

My AC went out. I'm positive there's a capacitor problem since I can actually kickstart the fan motor but it doesn't have any effect on cooling, which made me think that the capacitor (or another one) may also be required to start the compressor. That brings two questions:

Is there anyway I can identify the capacitor (or capacitors) from the label without having to open up the casing? (it's raining, not due pure laziness)
Anyway that I can diagnose a bad compressor, or leak knowing that the capacitor is bad, without changing the capacitor? (I don't hear the compressor humming after I kickstart the fan or before.)

Here's the only label I could find:

You are probably correct on it being the capacitor.  Most time the compressor and ODM (outdoor fan motor) capacitor are combined into one.  If you can get that capacitor out (looks like a small tin can with 3 prongs coming out the top) and it looks puffy, most likely bad.  You can easily check this if you have a decent multi meter like a Fluke.  Otherwise just take this one with you to your closest AC supply house and get a new one.  If nothing else, you will have eliminated this very common issue.  I've replaced mine even though they haven't failed but were showing some signs of puffiness.


Switch power between two appliances or power strips? I am constantly having to unplug my computer's power strip to plug in my portable AC unit, both because only one will fit into the one available plug I have and because the AC unit claims it can draw up to 13 amps, and I don't want to try and run it and the computer gear on the same 20 amp circuit.

Is there some kind of switch I can get to split the power from the outlet in two, but that only energizes one output at a time? Then instead of un-plugging and re-plugging things constantly, I could just flip the switch.

I could just chain both loads on a normal 15 amp power strip, but that sounds like an easy way to push a power strip beyond its rated current limit.

A 3-way switch, A duplex socket, a length of cord with plug and a nice box will do it.

Attach the live from the cord to the common on the 3-way and attach the 2 traveler connections to the live side of the socket and break of that tab.

Pigtail earth to everything that needs an earth. And make sure there is adequate strain relief where the cord exits the box.

That way if the switch is on one position only 1 side of the duplex gets power, if the switch is in the other position the other side gets power.


What size wire for a 100 amp sub panel in a barn? I am installing a 100 A sub panel in my barn which is 170 feet from the main panel. 100 feet will be underground and 70 feet will be through the crawlspace underneath the house. My main panel is 200 A.  I want to use aluminum wire.

The barn measures 28' x 50'. Within that, there is a 12' x 20' workshop. I'm planning on running lighting, and power tools. I will have gas heat so I don't need to heat the place electrically.

I have a very strong sense of already having answered this question.  If this is a dupe, I apologize.

For a 100A main breaker the smallest wire you can think of running is #1 aluminum.

If your breaker is 100A, your largest expected load ought to be 80A.

You do have a considerable distance there, and it's worth thinking about voltage drop.  Wire salesmen will tell you to compute voltage drop based on breaker trip and 3% drop.  You are much more correct to base it on actual expected loads and whatever drop will keep it less than 8% for all runs from main panel to final outlet. Since this will be the bulk of the run, we can give it 6% to play with, though less is nicer.

When we do a voltage drop calc on #1 aluminum, 80A (the largest expected load allowable on a 100A breaker), 240V and 170 feet, it computes out to 2.75%.  *Well, then. We certainly don't need to bump wire size here**.

#1 aluminum is the right stuff.


How should I wall mount a TV with one metal stud and a gap between the drywall and exterior block? I am mounting a TV on a wall (see photos).  There is a 7/8 inch gap between the drywall and the exterior, and a single metal vertical stud (Florida) as indicated.  I want to center the TV, which is also indicated.  I generally use toggle bolts for mounting on interior walls, but I do not think the gap is deep enough for them to open.

How should I mount here?
Should I take advantage of the concrete (cinder block?) exterior wall?

I would definitely take advantage of the block wall. I would use 2-1/2" tapcons with 1/4" fender washers straight through the drywall and than through some type of 7/8" spacer, and finally into the cinder block. The 7/8 inch spacer will prevent the screws from collapsing the drywall as the screws are tightened.   It would be best to use the largest TapCon fastener available. I believe they market a 1/4 inch diameter screw that has 3 versions: Flathead, Roundhead and Hex-head (hex's are easiest to grip and drive). The 1/4 inch screws will need a 3/16 inch concrete bit. I would use 4-8 of them depending on TV weight.


Breaker feeding an electric heater trips after one minute I purchased a Comfort Zone Heater.  Model CZ230ER.  It is a 7,500 watt 240V unit.
 This was installed with 10/2 wire to a brand new 30 amp breaker. Once the heater has been running for about a minute it trips the breaker. I have verified there are no shorts.

I do have it about 60 feet from the panel and my wire conduit was only 25 feet long.  The connections are made using wire nuts mounted in a metal box.

Any thoughts?

As noted by isherwood, you are pulling too much power. 7,500 W /240 V = 31.25 A on a 30 A circuit. Circuit breakers are typically designed to handle a somewhat higher than rated current for a short time - e.g., motor startup, a really high current (e.g., hundreds of Amps on a 30 A circuit) for an extremely short time, and a moderate overage for a moderate amount of time. This actually matches well with another rule: continuous loads should not exceed 80% of the rated circuit. In the case of 30 A, that means your continuous load should be no more than 24 A = 7,200 W.

So this is actually normal operation.

You need either a slightly smaller heater or a larger breaker with matching appropriately sized wiring.


Sub panel neutral and ground not bonded so why continuity between them? I have a 125A GE PowerMark Gold Load Center "subpanel" at my detached garage. Subpanel has 2 hots, one neutral with no "connected" ground between panels. The subpanel ground bus bar is tied to a local 8ft subterranean 5/8" grounding rod. 50A branch breaker at main feeding 6/3 wire about 100ft tied directly to the subpanel inlets (H/H/N). Per NEC, the neutral and ground in the subpanel are not bonded (i did not screw in the green bonding screw that came with the panel).

All the outlets including GFCIs all work correctly. When I test panel buses with my meter in the garage I have 120v between neutral and each hot and have 120v between ground and each hot. Sounds good right? Then why do I have continuity between neutral bus bar and ground bar also between neutral bus bar and panel box itself?!? I thought that if I don't insert the screw, then neutral should be "separate" from ground and panel metal box? Or is this normal?

The feed for your sub panel comes from your main panel the grounded conductor neutral and grounding conductor equipment ground are connected in the main panel so measuring continuity in a sub is normal even when the grounded conductor is isolated from the box and the grounding conductor.
This is normal the resistance value is usually quite low just a couple of ohms or close to zero. The length of wires and any resistance at the connections is all there is.


Why does my drill bit destroy the screw head? I have a craftsman drill which I use for drilling. When I use a screwdriver head to fix screws in drywall or wood, it keeps on destroying the head of the screw. So much so that the screw head is unusable.

What I am doing wrong? I have the drill on the slowest possible setting of 1.

Edit: This is a battery operated drill. It looks similar to the one in the picture below.

It is possible that there are several reasons for the screw head destruction.

You may be using an electrical tool that is not at all suitable for driving screws. Some tools designed for drilling holes are not going to offer enough torque at a low enough speed to properly drive screws. If your tool starts out with a huge burst of speed it can almost certainly lead to immediate stripping of the screw head.
You are using the wrong size driver bit for the type of screw that you have. If the screws are Philips head be aware that there are multiple sizes of drivers such as #1, #2 or #3.
You may attempting to use the wrong style of driver with the type of slot the screw. Do not mismatch the likes of Philips and Pozidrive. There may be other specialty type slots that are also similar but require the proper drive bit selection.
It may be that you are not properly aligned with the axis of the screw. Proper installation of screws with a driver requires that the driver be directly in line with the axis of the screw.
When driving screws with a power driver is in necessary to apply a pressure on the driver to properly keep the driver bit in the screw slot. Without proper pressure the bit can run out of the slot and strip the screw head.
It is possible that you did not properly prepare the medium into which you are trying to drive the screws. With many screws you will need a pilot hole in the area where the threads are to engage with the medium. If you are attaching another piece to the base medium you would want to provide a screw body clearance hole to the mounted piece. This can actually result in a stronger screw joint as well.


How do I share the same cold water pipe for both my dishwater and washing machine? I have one cold water source, the pipe looks like this:

I would like to connect two of these pipes this the source:

How do I do this?

The best I could find was something like this. But the connectors are too narrow for the pipe, and the tap needs to be in a Y shape ideally, so that both pipes connect roughly horizontally.

You could make a manifold by adding a T to the copper and 2 90's so they both come out where you would like It looks like there is enough room to do this.


Should a gas water heater be shut down if the water main has to be turned off? I have a brand new AO Smith 50gal gas water heater. Today there was a burst pipe from the cold spell we're having currently, so I had to turn off the water main to the house until the plumbers get here tomorrow.

With that, nobody had used any hot water all day so it should be full, but do I need to turn the water heater off until the water can be turned back on tomorrow to avoid any damage etc?

Water heaters have a dip tube on the cold water side that puts the cold water into the bottom of the tank. If water pressure is lost on the cold water side, the tank can siphon down through the cold water inlet till it reaches the bottom of the dip tube. Then since there's no water in the tank to absorb heat, the dip tube can melt and the tank can be damaged.

It would be best to at least set the heater so it is on pilot only.

Note: Manufacturer AO Smith states in their manuals that their gas water heaters must not be operated without being certain it's filled or with the cold water inlet shutoff valve closed.


Risk of insulation triggering mold growth? The unfinished basement gets water which is pumped out with a sump pump. (Water from heavy rains percolates into the basement.)

Company A gave me an estimate to insulate the attic.  So did Company B, but B said I need to do some landscape architecture first to eliminate the basement moisture, because otherwise, tightening up the house would make it much more likely that mold will grow, and therefore I should solve the humidity problem first, prior to adding insulation.  Does this make sense?  Note: I use a dehumidifer as needed.

The advice to remove water before it comes in is sound but if you run a dehumidifier and the rest of the house isn't extremely tight, it seems unlikely that insulating the attic is going to cause a major difference overall.

It really isn't a problem that your land is flat.  The grade required is very sight because the actual drainage will be to a pipe.  If you live on a street with a storm sewer, it will drain to that which will be below your yard regardless of how flat it is.

The biggest source of water is likely your roof, not the neighbors pool.  If you have old clay drainage, it's probably clogged and cracked and mostly non-functional.  And it's probably installed right up against the foundation.  This means water comes from the drain spouts, goes into the clay pipe and then (because it is porous) bleeds out around your foundation because it has no where else to go.

Contemporary drainage is completely different.  It takes the water direct from the downspout to non-porous PVC and takes it away from the house, typically to a storm sewer.  You can also add drains to other areas of the yard where water pools.  All of this may be subject to code.


How do I get leftover tape stickiness off of plastic surfaces? Okay...there's kind of a long story behind it, but I have left-over stickiness on the front of my alarm clock because it was bright, and I didn't notice a switch on it. It's from scotch tape that's been removed, and it's making the alarm clock rather hard to read.

I've tried cleaning it with a wet cloth, but it wouldn't get it off. I also tried scrapping it off with various things, but I couldn't get stuff flat enough so it only took off little strips. (Some things took off some of the alarm clock's plastic too...)

Any tips would be appreciated, and the easier/cheaper, the better.

Goo Gone! - they claim that it's safe on any surface, and I haven't used it anywhere that it's caused damage, but check a small spot first just to be safe.

If you want to try something cheap, you could always simply get the stickiness off with more tape, but that probably won't work with old grungy remains.


Looking to setup a 100Amp panel in my attached garage and have ideas/questions I want to install a 100 Amp panel to my attached garage.  The location is about 50-60' from my service panel, which is 200 amp utility service.  The purpose of this circuit is for a small pottery kiln and circuits for things like a table saw, miter saw, drill press, misc. small things and new lighting.

The kiln draws single phase 240 @~27-35 amps, recommended a 50 amp breaker using a standard 6-50 receptacle.

The workshop will be probably 2-3 20 amp circuits and a 15 for the lights.  There will also be a 20 amp circuit dedicated to ventilation—the fan load is so far < 5 amps, just don't want to limit it.

After a lot of looking around and researching it seems like the best option is to put in a full real panel like this one:

which should give plenty of expansion room and additional safety and other options.

My plan is to bury conduit from my main house panel to feed this new breaker panel in the garage.  Looking into these options and the desire to save money given the price of cable it seems like 1-1-1-3 SER Aluminum cable could fit my needs and should fit in 2" Schedule 40 conduit. SER is not allowed to be buried even in conduit

The problem is when trying to verify this I find a whole lot of arguments but not enough solid code reference as to whether SER cable can be buried in conduit (raceways?). Yup this is not to code, cable must be rated for wet locations to be buried apparently.

While I do want to save money, this has to pass inspection so that is my primary concern.  Seems like if SER is not allowed to be put in buried conduit I need to use THHN or perhaps better XHHW?  I have worked with aluminum wire before just at much lower gauge so not too worried about being able to handle it. (I will be pulling a permit for doing this).

Questions about cable run:

What is the proper type of cable for this run in conduit? SER, USE, THHN, XHHW, XHHW-2? Figured out it should be THWN-2 Not sure of an AL alternative yet though Will be using XHHW-2 CU, found a legit online source.
Can I do this with aluminum wire without having issues later?
My primary goal is 100 amp and I doubt I'll need more than that in the
garage so it doesn't need to be overbuilt too much.
From my research, do I need to bury the conduit at least 18 inches?

For the garage panel I know that since they are not within sight range or reach of each other I must install a main breaker in the garage panel to shut its power off but I had some additional questions there.

I plan to feed the run from 2 50 amp breakers in the main panel; is this
accurate/necessary?  Okay, so this was wrong:  Changing to single 100 amp breaker.  Even checked my notes again and I had this right so derp on this, lol
Should I also put in some kind of service disconnect before the sub
panel in the garage for any reason?

My locale is the U.S. and my city has adopted the following:

2015 International Residential Code (IRC)
2015 International Building Code (IBC)
2014 National Electric Code (NEC)
2015 International Plumbing Code (IPC)
2015 International Mechanical Code (IMC)
2015 International Fuel Gas Code (IFGC)
2015 International Energy Conservation Code (IECC)
2015 International Swimming Pool and Spa Code (ISPSC)
2015 International Existing Building Code (IEBC)
2009 ANSI (As referenced in the 2009 International Building Code)

I tried to provide as much information as I could but let me know if more details/clarification is needed.  Thanks for the help!

The type of cable you linked to is SE cable covered by Article 338 of the National Electrical Code. It connot be used underground with or without a raceway. Here is the pertinent code language.

338.12 Uses Not Permitted.
(A) Service-Entrance Cable. Service-entrance cable (SE) shall not be used under the following conditions or in the following locations:
(1) Where subject to physical damage unless protected in accordance with 230.50(B)
(2) Underground with or without a raceway

Notice item 2.
You could use several other types of insulation in a raceway, including THHN, XHHW, XHHW-2. USE is for direct burial and can be used without a raceway except where exposed to damage so you need to sleeve it in PVC or metal raceway above ground.
Aluminum also needs an anti-oxidation compound such as NOALOX or ALNOX, there are many brands.
Rigid or IMC conduit can be buried only 6" deep. Table 300.5
SE cable can be used as a feeder for interior wiring so if you kept the feeder inside the house and garage without going outside you could just protect it with PVC in the garage and be good. Or you could run the cable outside just not underground.
You will need a single 100 amp 2 pole breaker to feed the sub panel. 2 -50 amp breakers is not acceptable by the Code.
A separate disconnect is not required. The panel in the garage is not a motor so the "within-sight rule does not apply". The breaker in the main panel can act as a disconnect. You actually don't even need a main breaker in the panel if you don't want one. You can buy a Main Lug Only panel if you wish. The main only panel you linked will do just fine without a main.
Good luck and stay safe!


How should I hook up my generator to a manual transfer switch? I have a couple of questions about hooking up a generator to a manual transfer switch and I'm really hoping somebody with knowledge can help guide me here.  The idea is I will have an exterior weather-proof plug that I can plug the generator directly into outside, and have that plug wired to a transfer switch inside that is wired to my main panel (only the circuits I plan to use if the power goes out - probably 10 circuits).  The specs of my generator that I think are relevant are below.  I think my questions will be pretty basic for somebody experienced with this.

10,000 watt peek surge output, 8000 rated
15HP, 420cc, Air Cooled, OHV, 4 stroke engine (horizontal shaft)
Regulator: Automatic Voltage Regulator
Low oil shutoff system
4 standard outlets. Fully protected 110V.
1 twist-lock outlet. 240V 30amp outlet, NEMA L14-30R
1 twist-lock outlet. 120V 30amp outlet, NEMA L5-30R
1 DC outlet, 12V, 8.3amp. Convenient for charging any 12V battery
Max Current 60Amp @ 120V, 30Amp @ 240V

My main house entrance panel is 200AMP.

My questions are:

Would I only want to plug into the 240V outlet and run that cord to an exterior 240V plug and then wire that to the transfer switch?  Would that power everything I need?  I don't plan to ever run the dryer during a power outage (will dry clothes near the wood stove).  Is there anything else that would use 240V?  If I am not running anything in my house that is 240V is it better to run from the 120V plug on the generator?
When the last listed spec above (Max Current 60Amp @ 120V, 30Amp @ 240V) says Max Current 30Amp @240V, this means that I can draw a maximum of 30 amps simultaneously with the 240V output?
Why does it say "Max Current 60Amp @ 120V" when just above that it says "1 twist-lock outlet. 120V 30amp outlet, NEMA L5-30R"?  Is the 120V outlet 30 amp or 60 amp?
Also, do I need a 60 amp transfer switch to get the maximum out of this generator or 30 amp?  or higher?

I know it's a lot of questions but hopefully somebody can answer them.

I will join longneck, you need to give to give this one to a pro.

If you do not understand about back-feeding a circuit, already, it is too easy to kill someone. I say this without exaggeration.

The biggest problem with running a generator with a transfer switch is that you have to wire it into your main panel.

For basic protection of life, (as well as the law,) it must NOT be possible to have your generator and the power to your house on the same wire, at the same time.

This is not a case of, just for a few seconds, or I would not do that, or I will triple check a written list.

It must not be possible under mechanically, electrically, on with quantum physics.

The reason is that if you put power on the 'dead' wires to your house, it is possible to kill someone a mile away, or more.

Emergency workers expect down lines to be dead. Yes, they do check first, but that does not mean that the situation can not change while they are working on them.

Transformers work backwards, low voltage at your generator (240) quickly becomes high voltage (thousands).

And sometimes people, and pets, or cars, just do not even see a fallen power line.

This is a case of some money to a pro vs life.


Can I install an L-Bracket at an angle to match the direction of the load (for a Hammock)? I am wanting to hang a hammock on my deck from two large wood pillars (similar to those on a pergola, though these are permanent).  I cannot simply install hooks as I also need the hooks to stick out at least 6" and ideally 8-10"to keep the hammock away from a hand rail.
So my plan is to install an L bracket that would run perpendicular to the hammock ends, placing the hammock away from the pillars (and away from the fence).  But the force would then be down and pulling inside towards the hammock.  Should I install the L-bracket on a slight angle so that it resists downwards as well as inward load?  Other ideas?

The idea that you are talking about with just a common "L Bracket" is just not going to be a safe and workable solution. The forces on the ends of a hammock are tremendous and any mounting of a the simple bracket just is not going to perform as needed. Since you are planning a long projection of 10 inches or more you are going to need to plan on a much sturdier support mechanism.
For the vertical direction you should plan for an angle member that extends from the end of the bracket down a good 15 to 20 inches lower on the post. To deal with the intense force the hammock will be trying to pull the two brackets together you will need some additional bracing that extends from the end of the bracket out in a horizontal direction. If there is a cross member already between two posts to which you attach the brackets you can place these horizontal braces in either direction under compression or tension. It may even be possible to use a light piece of cable in tension for this purpose.


Updating thermostats to single system I have a three floors in my house, each controlled by it's own thermostat (separate air handlers and mechanical valves on furnace).  Baseboard heat.

The three thermostats are controlled separately, and it's getting a pain to manage them all.  I would like to update to a smart thermometer (Honeywell Lync, Nest, Ecobee), but I was wondering if there was another system out there that could control the three zones correctly without having to install three thermostats.   Any thoughts?

My only other thing I would like to solve is the multiple rooms in one zone.  Particular thermostats have a "remote" temperature sensor to help regulate heat.   Does anybody have any thoughts?

There are other ways to control multi-zones, but they're usually more expensive than smart thermostats.  Ecobees are the only thermostats that can be (affordably) controlled in groups via their web portal.  As well, the newer ecobee3 model has remote sensors that can average "comfort" within a zone.


Can I remove the bathtub -- just the tub -- without shutting off the water supply? I have to replace my bathroom subfloor due to water damage from a leaking toilet.
Therefore, I need to move my bathtub, replace the subfloor underneath it, and reinstall the tub.
However, there is no separate shutoff water valve for my bathtub, and it's not viable to shut off the main water supply because this project will take me days if not weeks.
It looks to me like there's no need to shut off the water: My bathtub is a bathtub/shower combo, with the faucet and showerhead built into the wall, not attached to the tub itself. (Pictured below.)
Can I safely remove the bathtub -- just the tub -- without shutting off the water supply?
(Correct me if I'm wrong, but it seems to me the tub itself is just a ceramic basin with a drain attached, with all the actual waterworks floating above it unattached.)

The drain parts (the drain assembly is called a waste & overflow unit) can be disconnected from above, there should be no other direct connections to the tub.
Just unscrew and remove the overflow trip-plate and disconnect it from the stopper mechanism (called the bucket & wire assembly). The drain strainer can be removed from the tub drain shoe by unscrewing with a special tool called a spud wrench.
The main problems with this idea are:

the tile/wall treatments (as mention by other commenters) are usually configured such that they overhang the integrated lip of the tub, which means the lowest tile course would have to be removed (see pic below).
some (many) bathtubs are cast iron and extremely heavy, making removal without significant alteration difficult. On more than one occasion I have had to demolish the tub in-situ to get it out.


What kitchen counter material would you recommend and why? What are the pros and cons of various kitchen counter top materials?

Granite
Corian
Concrete
Laminate
Quartz
Silestone
Other

We are happy with our Granite.  The only drawback is that we have to watch out for stain's - from oil or red liquids like red wine.  And even then, as long as you don't let it sit overnight, you are fine, just wipe it up.  After living with Corian and Formica, the ability to place very hot pans on the surface it a must.  I can't tell you how convenient that is.

depending on the style of granite and edge you use, it may actually be just as cheap as many of the other "cheaper" alternatives.  We found that going to the local Granite supplier, was way cheaper than buying it from a kitchen place or major home improvement stores.  In our case, we started at Home Depot, and we wanted to see larger samples.  They told us to go look at their supplier's location.  We went there, and they were like, just buy it from us directly, we not only supply it to Home Depot, but also install it for them, so we completely eliminated the middle man.

Corian is also soft, and can be scratched.  They will tell you, "we can fix scratches, and buff it out", but that costs money.  Why not just get something that can't scratch.

I am not 100% familiar with all the others listed.  I would just recommend going with something that is heat resistant and scratch proof.  If any other the other alternatives over granite are also less porous (resistant to stains) that would be a plus.


Old switch has four wires and no discernable ground I am trying to install a decora smart switch for my front home lights. The switch is in a box with the hall light switch and a switched outlet switch. I think the front lights switch is a single pole but not sure how to connect everything. Thanks in advance.

I think I see what is happening.  Many devices (switches, outlets) allow you to connect via either the screw terminals or the "backstabs" as we call them (with some contempt because they tend to fail a lot).

You're supposed to use only screws or backstabs.  But the screw is connected to the backstab internally, so this is a possible way to use both, which splices the  two wires and also connects to the device.

It's just a lazy cheatey way to splice both those wires to the same screw without using a wire nut and pigtail.

Now, I think this is a 3-way switch, but you didn't mention it being controlled in a second location, and the wiring doesn't make sense for a 3-way, so I think this is being used as a 1-way switch simply by not using one of the brass screws.

The two yellow wires are definitely using the "use the switch as a splice" trick.  Both those wires should go to a wirenut, with a third short pigtail going to that same switch's screw.  Since your lights are in three locations, my guess is the two yellows are both switched-hot running in different directions out to the lamps.

I can't quite tell if the black wires are on the same "screw", but it looks that way. Note how the

It's a little harder to tell whether the blacks are on the same "screw"... But you see the stabbed black is a pigtail to a wire-nut. That is surely supply hot being distributed to several switches. Which would make the screw trick simply extending that hot further. If so, the wire on the screw now should go into that wire-nut, and the pigtailed wire should use the screw.

If it works out as I describe, now you have 2 wires going to that switch: the black is supply/always-hot/line, the yellow is switched-hot/load.  If your smart switch needs neutral, you can add a white pigtail to that bundle of neutrals in the back of the box.  (which you should not otherwise be messing with!)


The deadbolt on the door is broken preventing opening the door. Schlage Deadbolt won't unlock to open door so I took off the lock portion to try to open it but the spring broke...nothing moves. It looks like it wasn't installed correctly, because there wasn't a strike plate and I can see that the bolt is stuck/jammed in the door frame.  What's the best way to get the bolt out without damaging the door? Thanks.

This may  just be friction from the door frame pressing on the bolt, caused by humidity changes or a shift in the frame. If so, pulling or pushing on the door while trying to retract the bolt may loosen things enough to let you retract the bolt.

If not, you can try pulling the hinge pins and removing the door from that side.


PVC toilet flange replacement problems Background:

I wanted to replace the wax ring on my toilet but when I took it apart I found that the flange was in bad shape. The notches that hold the bolts were broken out. That, I think, led to the toilet wobbling, which led to a leaky wax ring.

The flange was screwed down and the screws were rusty and I was stripping them trying to get them out, so I had to chisel the flange apart and remove the screws with some pliers. The flange was the kind that fits inside the pipe. It looked like this after I had broken up the top of the flange and removed the screws:

That's a tile floor, slightly crumbly around the hole (it doesn't look as bad in person). You can see the little piles of rust where the screws were. Finally, I used a saw and chisel to remove the last of the flange from the inside of the pipe.

The problem:

Once I got the flange out, it looked to me like there was another layer in there. I mean it looked like the pipe contained small second pipe, into which my old flange had been inserted. I began chiseling that out as well when I stopped and wondered whether I should be doing that. It didn't seem that the inner layer was coming out as cleanly as the flange had done. At this point it looks like this:

I believe that's purple PVC cement around the inside. You can see that there appear to be two layers. On the right you can see where I started chiseling out the inner layer. On examining a bit that I chiseled out, it does appear to be an inner layer. Here is a photo of it. You can see some printing on the outside surface (by which I mean not the purple side).

The question(s):

What now? I'm up to my neck in this project and I'm not sure how to proceed. What do I need to do in order to prepare this pipe to accept a new flange? Should I stop now and just install a new flange in the pipe as-is? Do I need to remove that inner pipe? And the big question, is it time to admit defeat and call a plumber?

Investigate the push tite replacement flange

It may be that the rubber gasket will form a seal below the damaged portion of your waste pipe. If it slides into the pipe and seats against the floor you can anchor it to the subfloor and you're back in business.

To see a variety of parts made for your kind of trouble look here


Why does netural wire on switch bypass circuit breaker? I am switching out my old switches for automated one and in one of the bedroom I ran into an odd situation.

-The OLD switch had a: black, black, green wire
-The new switch have a: red, black, white and green wire

I turn off the circuit breaker for that bedroom and confirm it was off.  When I wired the new Switch, I connect all the wire BUT noticed that if I connect the White wire to the switch, it somehow bypass the circuit breaker and there is power to the switch...

If I don't connect this white wire then, the switch will work once I turn on the circuit breaker for that bedroom on again.

Note:  When the power was on (and nothing was connected to it), the voltage tester show that there was only 1 wire that had power (and it wasn't the white one) so i assume that the white would be the neutral.

Anyone got any idea on why the white wire would bypass the circuit breaker?

Edit:  It also appear that with that white wire, its now part of the masterbed room circuit...

In my case, all these switch have netural wire which is fine, as the rest of the house got changed over to these smart switch already and are working as expected.

It is only this one bedroom (lets call this "Bedroom A")light that it is interesting.

In which if the Netural wire in Bedroom A is used then it become part of a different bedroom circut (lets call this the "Master bedroom".

The only thing I would image this is that (as this was an older house) that for this Bedroom A... that whoever ran the electrical, just splice the neutral from "Master bedroom" to the "Bedroom A"

But I am interested in see what other think why using the Neutral wire in "Bedroom A" would cause that switch to become part of the "Master Bedroom" circuit..

You may want to pause to learn a little more about switches.

The first concept is that powered things need power.  Power moves in loops, you you need two wires.  It's perfectly possible to set up a power loop so it is hot-to-hot, in which case you really need to switch both wires.  A great example is an air conditioning condenser in North America.

However that is more expensive, so neutral is a concept we established to make wiring easier. We set up neutral so it is near ground potential, so it's considered not hazardous.  And so there is no need seen to switch it.

On an old fashioned light, the only thing that takes power is the light.  So the switch is a simple mechanical human-powered device, and it only needs to interrupt (break) one of the wires.  It's safer to interrupt the hot wire.

On a new fangled smart switch, the switch also takes power.  So now you have two powered devices, and both of them need a full loop of both hot and neutral.

The smart-switch needs always-hot and neutral so it can be always-ready.
The lamp proper needs switched-hot and neutral.

Note that switches did not need neutral before, and suddenly now they do.  That's a real problem for a lot of old in-house wiring.   Sometimes you just can't install the smart switch.

There are also smart switches which do not require neutral because they use "the incandescent cheat", exploiting a fact about incandescent bulbs where they act like nearly a dead short until enough current flows to get them hot.  The smart switch (on an incandescent light) can place itself in series with a turned-off bulb, and leak enough current to function itself.  However the power supplies in CFLs and LEDs are designed as voltage devices not current devices, and respond to "the incandescent cheat" in strange and unpredictable ways.

There's one more concept that comes up a lot.  Why doesn't neutral have a circuit breaker?

That concept entirely relies on the notion that hots and neutrals should be married monogamously. That is, every hot should have 1 partner neutral and use only that neutral to return current. The neutral is the same wire size as the hot.  If this is done properly, the neutral cannot overload unless the hot is also overloaded in exact proportion.  Since the hot has overcurrent protection, that will protect the neutral also.  That's the concept.

Of course that does not account for people who don't respect that concept.  I see circuits all the time where a device is wired with the intended hot, but any "neutral of convenience".  The easiest way to detect this is by adding a GFCI/RCD to the circuit and putting a load on every outlet.  The GFCI compares current flow on "hot" to "neutral" and trips if they are not equal.


180 degree plug adapter I am trying to charge my car at my workplace however the 110V plugs in the garage are "upside down" and my charging cable is designed to hang downward when the 110V plug is "right side up".

Is there a 180 degree plug adapter? I've looked around for it (I'm sure it exists) but can't find one beyond a very short extension cable.

Since some corporations are really grouchy about changing anything, and you may well run into this same problem when trying to charge up at some random location, I would go with either a 3-foot extension cord or a power strip.  In either case, make sure the wire gauge is sufficient for the expected charging current.
Keep this "adapter" in your car next to the charging cable and you'll be compatible with any outlet anywhere.


How could I motorize my venitian blinds? I just moved on to an appartment which have a set of 9 venitian blinds.

Each come with 2 actions : a string you pull to lift the blind, and a stick you spin to spin the blades and filter more or less the light.

I would like to motorize the stick and remote control all of them. (I'll probably never lift them)

I know how to use arduino with a raspberry pi to remote control things with radio emetters, but I have no clue what to use to motorize things.

The stick is made of plastic, a little elastic but solid though, and the force needed to spin them is really low (2 fingers are more than enough). More, you can spin the stick a little too much, it wont cause any damage, so there is no need for sensors yet.

Here is a picture of the subject. There are 9 of them and some are really high so I only have access to the bottom of the stick.

So, for this project, what should I consider regarding the motorization ?

If you have experience with Arduino, you have most of the project in good stead. Servo motors and stepper motors are commonly used with Arduino to accomplish similar tasks. Your answer lies as much in your budget for this project as it does for the selection of motors.

A 360° capable servo will rotate when driven by the proper code, operated by an appropriate servo driver board. Non-360° servos are limited to about 180° movement, far too little for your rotation needs. You can find code libraries to cover this aspect, as well as appropriate hardware from the multitude of Arduino sources, Sparkfun, Lady Ada, Amazon, etc.

The other option would be a stepper motor, stepper motor driver boards and code libraries. As you've noted that a bit of overdriving isn't a problem, you can get away with some slop in the positioning. A stepper motor is commanded to move a specific number of steps. If during this command execution, movement is impeded, the motor keeps counting and may stop short. Some stepper motors also have encoders to report location/progress, but that increases the price, of course. Servo motors by design "report" location and attempt to move until success or servo motor burn out.

Stepper motors would have sufficient power, even those among the low end force models, while servos would require purchase of the higher end components in order to get working devices.

Mechanically, I suspect you'd have an easy time of connecting either type of motor. A housing/bracket for the motor, a coupling to the rod, even a simple piece of vinyl or rubber tubing, and you'd be ready to go.

I expect the difference between the price of parts required to create nine sets of drives and the price of nine factory-motorized blind sets would be substantial, in your favor.

As a DIY project, it also would provide you with a sense of accomplishment. What value can one place on that?


Frigidaire Electric Range trips arc-fault circuit breaker in another room I have a problem that occurs intermittently in several different apartment units.  Kitchen has Frigidaire Electric Range.  Living room (LR) and bedroom (BR) have 15 Amp AFCI circuit breakers that control ceiling lights in the kitchen and LR & outlets in LR.

At times when one or more burners are in use on the range, the AFCI that controls Ceiling Lights in LR & Kitchen and outlets in LR will trip.  I am changing out the 15 Amp AFCI because I don't see anything wrong.  It doesn't do it all the time and it has done it in at least 5 different apartments.

All apartments are wired the same & all have the same range.  What the heck is causing this?

The surface burner controllers on electric ranges work by making and breaking the circuit to the heating element. I don't know the frequency at which this occurs, but this mode of operation would appear to have the potential to trigger an arc fault breaker or receptacle. See https://en.wikipedia.org/wiki/Energy_regulator

Therefore, some ranges might trip some AFCI breakers or receptacles. Is AFCI protection appropriate for a kitchen? I thought AFCI was for bedrooms.

Frigidaire is a name brand of range so I would first suspect the AFCI receptacle or breaker. What is the type (receptacle or breaker) and brand of AFCI device you have in the kitchen circuits of these apartments?


My bathroom fan brings air into the bathroom; should it? My apartment's bathroom fan appears to have been installed to bring a (small) amount of air into the washroom. I've confirmed this with a sheet of paper; pushing it against the grill I can feel a small amount of air being brought into the room.

Is there ever a good reason for it to be installed like this? It's noisy and is almost entirely ineffective at dispelling odours/humidity.

From what you describe it seems unlikely that the vent fan is actually installed to blow backwards. So it would be much more likely that the trouble you are encountering could be one of:

The back draft flapper may be stuck in a shut position. This is a device to close off the vent for air flow trying to come in from the vent pipe. Sometimes they are built right into fan housing where the vent pipe attaches. Other times the flapper will be part of the roof or wall vent where the vent pipe exhausts to the outside. In some cases there could be flappers in both locations.
The vent pipe from the from the fan to the outside may be filled up with dust, dirt or other debris. This could be from years of accumulation or debris blown in or carried in from the outside vent opening.
The vent pipe may be damaged, kinked or flattened. This could happen when workers were careless or for other various reasons due to remolding, adding insulation or re-roofing.

In all three instances there can be blockage of the airflow that the fan is trying to expel from the room. For a significant enough blockage some of the air flow will try to return back into the room around the periphery of the fan blades. This is likely what you are noticing when you held the paper up to the vent grille. It is often the case that a fan trying to blow into a blockage will generate a lot more noise than one that has a free flowing path for the air that the fan is moving.

The fix is going to require careful inspection of the whole vent system from the fan housing all the way through the vent pipe and out to the place where the pipe terminates the roof or wall of the building.


Are concrete blocks a cost effective, modern and strong solution to building a house? I do many different house designs in SketchUp. With a 500,250,250mm concrete brick I believe I could create the walls for a house for as little as £1,000. Roughly 1k bricks will be needed to create walls for this house. The concrete bricks will have 2 holes which will connect to the bricks below it creating long holes which concrete is poured down. Are there any problems that could be encountered with concrete bricks, or are walls everywhere just cheaper than I expected? Here's a mockup of the house.

If you can get past the appearance, here are some other considerations: 1) cost of installation of blocks, 2) wall insulation, 3) paint, 4) electrical, 5) larger foundation, 6) seismic loading, 7) future changes, 8) thicker walls.

1) Material cost of blocks is just the beginning. You'll need special shapes, (i.e.: lintels, corners, etc.). You'll need mortar, have you ever laid a block? It's difficult and slow. You'll need reinforcing (horizontal and vertical). You'll need grout in the cells to "hold" the reinforcement.

2) You'll need special insulation on the interior or exterior of the wall and then you'll need to cover that insulation with something.

3) Concrete blocks are porous and you'll need to coat the wall with a block filler before painting.

4) Installing anything in the wall like electricity, will be difficult.

5) The weight of the wall is significantly more than a wood frame wall, so the foundation will need to be larger too.

6) Heavy construction is critical in seismic zones and light buildings are critical in high wind zones. Wood framing is easy to add extra reinforcing (plywood), but block construction gets expensive, especially at openings.

7) Any future changes, remodeling, etc is more difficult than wood.

8) Because the walls are thicker, the building needs to be larger to provide the same size rooms as with wood framed walls. So, you'll have a larger "footprint" and thus require more roofing, attic insulation, etc.

...But fire protection may be better...


Replacing Outlet with Switch Middle of Run Trying to wire unfinished basement with new can lights.

There's an outlet mid height on wall at bottom of stairs that also powers a number of lights downstream that would be ideal location for switch for these new lights.

I want to replace the outlet with Lutron Caseta switch and simply run new 14/2 to the first can and so on down the line.  The switch only has two black wires...so one will go to pigtail hot and the other to the first light.

Is there a way to do this without the new switch affecting all the downstream lights/outlets?

Originally I was thinking switch loop but this layout would be simpler and no white wire serving as a conductor.  Just don't know if it makes sense.

Thanks for your assistance!

This will work fine. Switch loops are for when the power comes in at the fixture, its not applicable here.
One word of caution, you can't just go around removing outlets, the old 6 foot rule. You could install a two gang box and keep the outlet there or just install another one right below the exiting one, easy to just drop down the /2 cable.


Downstream non-gfci outlet needs to power a refrigerator The above picture is the backside of a non-GFCI downstream outlet.  I would like to plug a refrigerator into this outlet.  However, when I do the circuit gets tripped due to the surge of the motor coming on.

The outlet is in my garage at about 4 feet off ground level.

My question is this:  Can I do something to this outlet so that I can plug a refrigerator in without tripping the circuit?

Defrost Cycle

As discussed in comments, this problem does not happen immediately but appears to be related to the defrost cycle - in one test it took 7 hours until the breaker tripped. Assuming this is the GFCI tripping, which appears to be the case though that hasn't been stated clearly, that points to one of two possible problems:

The defrost mechanism itself is leaking current somehow, causing an imbalance which trips the GFCI
Water from the defrost cycle leaks to someplace that causes a ground fault. Exactly the kind of thing that a GFCI is designed to protect against.

So the question becomes: Is this the beginning of a potentially dangerous fault, in which case the GFCI may have saved someone from serious, even fatal, electrocution, or is this truly a minor issue, possibly even a design flaw, where the electrical leakage is so small and so hidden that it would never actually present a danger.

As Harper frequently points out, GFCI trips on refrigerators generally have far more risk of causing food poisoning and/or loss of food due to undetected problems than they do of benefit by preventing electrocution. So if the situation really is "not a real problem, just poor design that leads to GFCI trips every defrost cycle but safe to use" then the solution is to wire up a refrigerator-only receptacle off the LINE side of the GFCI instead of the LOAD side.

If, on the other hand, this problem is actually a sign of a potentially dangerous situation - perhaps caused by damage during the 5 years that the refrigerator sat unused - then fixing the underlying problem is a much better course of action.

No random person on the internet can make this potential life-safety decision for you.

(If it were me, I'd see if I could isolate the components of the defrost circuit to see if there was repairable damage. But that's me. And it is likely a non-trivial project to do that.)


Correcting a possible roofing error Our roof has a peculiar first row of shingles. In most places the first row extended beyond the L-Shaped metal holder by about 5/8". But in some other places it is almost flush with the metal piece. (And in these places we noticed deterioration of fascia boards.)

If this is an error, what is a corrective step?

On the roofs I've done, the shingles (or metal, in one case) extended 1/2" to 1" past the flashing.  It does not sound like this is the source of the problem for you.  The flashing should protect the fascia from a full water flow, if it is the correct flashing.  You describe it as L shaped, but it should have a kick out at the bottom ("drip edge").  I found a decent picture here.

In addition to a small overhang and proper flashing, the final defense for your fascia is a coat of paint.  If the fascia is not rotten, you should restore its surface, and prime and paint.


50 champion generator plugged into a Generlink 40 Amp Meter Mounted Transfer Switch Hello and thanks in advance, I would like to buy the Generlink 40 Amp Meter Mounted Transfer Switch but my champion generator puts out 50 amps.  Will this overload the switch.  I know it will only let 40amps into my panel and I'm fine with that.  i just don't want to overload anything.  Thanks

Doesn't appear to be a problem.  Supposedly, UL approved the instructions along with the device, and the instructions plainly invite you to plug in any generator with a compatible socket.

The instructions state the meter device has internal overload sensing/protection, and if your generator delivers more than 40A (because you drew that much), it will automatically disconnect the generator for you.

This doesn't even require any extra hardware; presumably if you overload the generator, it simply throws the transfer switch to utility power (which is dead, obviously).  Rather clever.


Which wire should be capped when replacing an old 4 wire smoke alarm with a 3 wire alarm We have to replace an old 4 wire smoke alarm, wire colours are: white, black, orange, brown, in our condo with a 3 wire smoke/co2 alarm. My question is which wire from the old system should be capped when I install the new alarm?

I'm assuming you also have a ground wire? You should use the orange wire as the interconnect, and cap the brown. You could even go as far as to use red electrical tape to wrap the orange wire near the marrette so it's properly labeled, but it's not necessary. Just make sure you're using the same wire throughout and it will be fine.

However, do be advised that you will need to replace all your smoke alarms.  Interconnected smoke alarms generally do not communicate between brands.  You will usually need to buy multiple of the same model for them to work properly.  This is especially true switching between 4-wire smoke detectors to a 3-wire model.  Is this a condo or apartment building?  If so, the smoke detectors are all interconnected, no?  In which case you probably should not be replacing just one, as that won't trigger the alarm throughout the building.

Lastly, 4-wire smoke detectors are often tied into a security panel.  Do you have a security system installed?  If so, firstly, contact your security company before disconnecting your smoke alarm, or you may get a visit from the fire department.  Secondly, you may not be able to switch to a 3-wire model.  It will prevent your monitored smoke alarm from working.


Dryer cross-wired - loud pop and no longer works? We were changing our dryer from a 4-prong to a 3-prong cord and my husband accidentally put the center wire on one of the other terminals. He plugged it in and ran the dryer for a few minutes, then turned it off, and as he was preparing to push the dryer into its place against the wall, there was a loud pop and the faint smell of smoke. He immediately unplugged the dryer and, upon closer inspection, realized his mistake. But when he corrected the wiring, the dryer would no longer work. We know it's not the circuit breaker as we plugged in the landlord's dryer and it's been running fine.

It's a Kenmore Elite HE dryer purchased in 2004. I replaced the heating element a few years ago and it's been going strong up until now. I'd really like to repair this dryer if at all possible. It's old but has been very dependable. But I'm not sure where to even start? (I'm not super handy either but I like to try.)

Are you sure you didn't trip the breaker or at least one side of it. Try turning the breaker all the way off. Make sure both poles are pushed to the off position. Then turn it all the way on. If you have a voltmeter then check to see if there is power on both poles of the breaker. It should read a nominal 240V.

If that isn't it, then try and locate the POP sound by seeing if there is a faint smell of smoke from the receptacle or the dryer. If it is the dryer, then chances are you have burnt up some of the wiring in the dryer and if that is the case odds are you are looking at getting a repairman on the dryer or buying a new one.

I say this because you have said you are not all that handy and tearing into a dryer to make a DIY repair requires a certain amount of mechanical expertise.

Good luck and sorry for the bad news.


Basement bathroom PEX branching to fixtures We're plumbing our new basement bathroom. The nearest fixture from the main hot/cold water line will be the vanity sink.
Can I run from the main line to the vanity sink (one faucet), and then branch to toilet and shower (no tub)? All with 1/2" PEX.
Distances:
Main line to sink = 15'
Sink to toilet = 5'
Sink to shower = 6'
Thank you.

I did something similar in my son's tiny house.
But I did an individual run to each item (kitchen sink, toilet, shower and bathroom sink) to limit the joints used to the ends only.
Much easier not to worry about leaks hidden in walls (just have to remember if fixing things with screws).
The professional plumber looked and said that was what he would do as the pipe is cheap and the consequences of one leaking tee joint are expensive.
A roll of the pipe (25m) is about 75 feet so you will still have some left.


Filling gap beneath hardwood floor (between floorboard and foundation) There's a sizeable gap between the edge of hardwood flooring and the foundation by this fireplace:

You can see that the wooden base the strip of floor was nailed too ends about inch early:

As a result, many of the nails in the strip were justing stick out into space and the board is one bad step away from cracking in half. My first impulse is to cut shove a 2x1 in the gap so the board won't hang over the edge. Is there any reason not to do this? Is there a special kind of wood I'd want to use to avoid termite / other problems in the future?

That's a good solution if you can hammer the wood piece in tight enough and below the bottom of the flooring.
Also you could pour in a floor leveler to the same height as the existing floor. Once it's cured cut a strip of flooring so that there is a 3/8 inch gap between the piece and the fireplace apron. Glue it down with a construction adhesive.
You could also remove the trim pieces that frame the apron. Install wider trim pieces to cover the gap (leaving room for expansion). Apply colored caulking to fill expansion gap.


Is there some type of coating I can use to prevent condensate on my HVAC ducts? I'm getting a lot of condensate on my HVAC ducts that run though my first floor (and HVAC blower) especially in July / August when humidity levels are outrageous (in NJ).  The 1st floor space space is rather frigid as one face of it is below grade so it's hard to convince the occupants to open the registers to dry it out (at least not without opening the windows and letting the humid air back in). However even on days when humidity is lower, I can occasionally notice a small amount of condensate build up which has clearly led to mold growth under the previous owners care. Further compounding things is the natural tendency for the cold air to make its way back down to the ground floor via the small gaps near return / air filter area and in the registers themselves.

I know most people say to just insulate it, but the previous owner did this in a few places (with neoprene peel-n-stick in some places, and standard batt in others) and it looks terrible, and it appears with standard batt insulation just provides another surface for mold to grow on.

Is there any sort of water repelling coating that that I could use to prevent the condensate from building up in the first place the way RainX works on car windows?

Is there some other trick I should be using to reduce humidity or condensate build up on the duct work?

I call it “The Coke bottle” effect. When you take a coke bottle out of refrigerator, it sweats on the WARM side.

The same thing happens when you start pumping cold air through your metal ducts in a warm atmosphere. (And vice versa for warm air.)

Paint doesn’t isolate the metal duct surface so you’ll have condensation.

I’d look to “duct insulation” which is made specifically for ducts. Some are self-sealing and have a peel and stick adhesive so it would be easy to apply.


Can IC-rated recessed lights come in contact with sheet plastic? I'm installing low-profile (slim) recessed LED IC-rated lights in my living room that has a drop ceiling. Above the area that one of the lights will go is a plastic sheet seemingly filled with old lathe and plaster (no idea why). I can't tell how much garbage is actually up there so would rather just leave the plastic alone.

Is there any problem with pushing the recessed lights into the hole right up against the plastic sheet? I know IC-rated means that it can come in contact with insulation - what I'm not sure about is how IC-rated fixtures differ across other materials.

Go ahead, although I'd stick a thermocouple up there and double check the temperature to be sure
NEC 410.116(A)(2) permits IC-rated recessed fixtures to be in contact with combustible materials in the manner you describe:

(2) Type IC. A recessed luminaire that is identified for
contact with insulation, Type IC, shall be permitted to be in
contact with combustible materials at recessed parts, points of
support, and portions passing through or finishing off the
opening in the building structure

As a precaution, though, I would use a cheap type-K thermocouple probe and meter to measure the temperature at the light-to-plastic interface after the light's been left on for a few hours -- anything under 90°C should be fine, as per NEC 410.115(A):

410.115 Temperature.
(A) Combustible Material. Luminaires shall be installed so
that adjacent combustible material will not be subjected to
temperatures in excess of 90°C (194°F).


Nest thermostat heating way beyond set temperature I installed a new (2020 model) Nest thermostat, which is replacing a basic battery-powered Honeywell thermostat that we had. The wiring is W/R/G/Y.
The Nest thermostat keeps heating WAY beyond the temperature I set it to heat to; it just won't stop. (When I go into settings it also reports that it's not detecting the W wire, even though I've carefully stripped and inserted that wire multiple times.)
The curious thing is that when I put the old thermostat back in, everything works fine. (And that old thermostat has always worked fine; we got the Nest Snow because we thought it would be a nice update.)
Additional information:

Our furnace is a 19-year-old (and soon to be replaced) Trane XV90 (variable speed, high efficiency, two stage).

This is the wiring for the old thermostat. I've had to put it back in because of the problems we've experienced with the Nest.

Did you put fresh batteries in the Nest?  No.  Because the Nest doesn't take batteries :)
So that raises a question. How does Nest power itself? It has a lithium battery (like a phone) but that has to be replenished somehow.
The answer is, Nest depends on the fact that thermostat wiring is in series with the furnace relay.  Power flows
            -----R wire--------------------------- THERMOSTAT
         /                                           /
        /                                           /
       /                                           /
TRANSFORMER                    -------W wire-------
       \                      /
        ------C wire----- FURNACE RELAY

Now, on most furnaces, the furnace relay is a physical relay.  They require a certain amount of current flow to "pick up" or actuate.  If current is too little, they will not pick up.
So if the thermostat leaked a small amount of current through the relay, it should not actuate.  So the Nest takes advantage of that.  It leaks that small amount of current - which typically will not actuate the relay on most furnaces - and uses that current flow to power itself.  This is the same way old style dimmers work.
There are two ways this can blow up.  #1 the relay may not be able to flow enough current to power the Nest.   #2 that small current may be enough to actuate the relay and turn the furnace on.   #2 is your problem.
Two ways to solve this.
Put a dummy load across the relay so current has a second path
            -----R wire--------------------------- THERMOSTAT
         /                                             /
        /       ---DUMMY LOAD--                       /
       /       /               \                     /
TRANSFORMER   /                 >-----W wire---------
       \     /                 /
        ----+-C wire----- FURNACE RELAY

Now current splits and follows 2 paths: through the dummy and also through the furnace relay.  Smart sizing of the dummy load will divert enough current to stop the relay from actuating.  On most furnaces.
Several companies make appropriate "dummy loads" for use with the Nest.
Add a "C" wire to the Nest
If none of these options work, Nest has the provision to take power directly off the transformer, by tapping the transformer via an extra wire: the "C" wire.
            -----R wire--------------------------- THERMOSTAT
         /                                          /     /
        /       -------------C wire-----------------     /
       /       /                                        /
TRANSFORMER   /                -------W wire------------
       \     /                /
        ----+-C wire----- FURNACE RELAY

We haven't seen the sheath of your thermostat cable; typically furnace installers use larger cable than you immediately need and simply wrap the unneeded wires around the thermostat cable sheath.  So you may have 1-3 more wires in that cable that are unused. If so, this is fairly easy.
A "wire multiplexer"
They make fairly complex powered gadgets which allow you to cram 5 wires worth of signal (R, W, G, Y, C) over 4 wires (or even 3).  However they are a mighty octopus to wire, and prone to creating very difficult-to-troubleshoot problems, so I disrecommend them until the "dummy load" option has been exhausted.


What flooring can be used for a gypcrete subfloor? My question is about what to do after the malfunctioning washing machine flooded the basement. We tried an acid stain on the 'concrete' floor. It failed. We followed with two coats of epoxy pain. It failed. A 'concrete' expert examined the floor and found it was gypcrete. Also there are cracks in the subfloor and a coring showed no moisture barrier or gravel base. The discarded floorings showed no sign of moisture or mold.

Research shows gypcrete lacks the chemicals for an acid stain reaction so we understand the failure (maybe). But, what are floor options now?

You have two major problems: 1) Gypcrete is designed to be installed over a wood support, not on gravel or soil, and 2) Gypcrete is not designed to be a final finish surface. That is to say, it’s not made to be walked on...you need a finish flooring, like carpet, sheet vinyl, wood, etc.

Call your insurance company and tell them about your washing machine problem and tell them the flooring (Gypcrete) needs to be removed. Remove it and then install a concrete slab.


Fuse blew, outlet didnt work, replaced outlet, still not working I was using some power tools in my garage and the fuse blew. I replaced the fuse but the outlet still didnt work. It was an older outlet without buttons so its not GFCI. The outlet is in the garage, and the downstairs bathroom light runs off the same fuse. After replacing the fuse the bathroom light works but the garage outlet does not. Beside the outlet is a switch for the garage light as well, which also doesnt work.
So I replaced both the outlet and switch.
When I plug anything into the new outlet (tried shop-vac and small lamp) it doesnt work and the garage light doesnt work either.
My plugin tester shows wiring is correct, nothing reversed or open.
With my multimeter I get 117 vots hot to neutral , 3 volts neutral to ground, and 122 volts hot to ground.
At the light fixture I get the same 117-120 volts cant remember exactly when the switch is on.
By all accounts when I plug something into the outlet or flick the light switch I should get power, but nothing happens. Seems like I've tried everything and am really scratching my head. Thought I would ask here first to see if there is anything obvious that I missed before calling electrician.
Any ideas? Thanks.

You blew another “fuse”
Well, it’s not meant to be a fuse.  It’s meant to be a solid wire splice. But it was weak to begin with, but the high draw from your adventure finished it off.
it’s a wire connection either at the last outlet that is working, or the first outlet that has failed.  You’ll need to check both of them.
Often, you can’t clearly identify the sequence.  If so, you’ll need to check all the outlets in the circuit including switches and lamps.
Both visually inspect, and also check tightness of the screws.  Note that you can’t do either one  on a “back stab” type connection.  As it happens, those are also the worst culprits in cases like this.  That’s why we don’t like them. Builders love them because they’re fast. But this is the price you pay.
Since you quite efficiently answered ThreePhaseEel’s questions, we can say definitively that the trouble is with the neutral wire.  That is the only one you really need to check.


Ceiling fan remote not working I lost the canopy bracket along with the receiver and remote to my ceiling fan while moving. I then ordered an exact replacement receiver and remote for the fan, and when I had someone install it, the remote still didn't work for some reason. Does anyone know what the problem could be?

you probably have the dip switches set differently in the transmitter compared to the receiver.  you just need to open the receiver housing, check the switches and make sure they are set the same in the transmitter (assuming same model, frequency, etc is correct)


What is wrong with this GFCI outlet? I have a GFCI outlet which is testing wierdly.  On one of the plugs, one prong tests hot and the other does not (using a Voltaware).  On the other plug, both prongs test hot.  The other outlets on the same circuit test fine.  I reversed the black and white wires and nothing changed.  Any ideas?  Will replacing the GFCI outlet resolve the problem?

A non-contact tester might give you a false-positive on the neutral in some cases.  Try testing the outlet with an outlet tester which will indicate if the hot/neutral are switched or open.  Alternatively you can use a multi-meter to test it.  If you are in the US, you should get ~120VAC between hot and neutral, but 0VAC between neutral and ground if the outlet is wired correctly.


How to add C wire to a very old 2-wire Lennox G16 Gas Furnace? I recently bought a Sensi Thermostat with Wifi to replace my vintage one. I thought it would work with my 2-wire heat only system because it has batteries , but found out that using the Wifi feature with batteries only with drain them in only a couple days. After searching forums and looking at the Sensi website, I will need to add a C wire.

I read that I can repurpose the fan wire (G) as a C wire by connecting it to the C terminal in the circuit board. I looked at the thermostat wire and found the fan wire (G) unused and stuffed into the wall. However, my system is so old that it doesn't have a circuit board, only a mess of wire nuts.

Where I should connect the C wire to on my old system?

According to the wiring diagram for your system (i.e. Figure 2 in the linked PDF) -- the yellow wire on the 24VAC side is the C wire (it's the wire that goes to the compressor but not to the 'stat in the diagram).  Just incorporate the green wire from the thermostat cable into the nut with the yellow and green wires in it on the 24VAC side, and you'll be set!


How is pre-wiring done for motion sensors / alarm system in new construction? In new construction, how is pre-wiring done for alarm systems, when then alarm may not be installed right away (or ever)?

It makes sense to me to actually install recessed door contacts (they're only a few dollars each) and run the wiring back. I suppose if using window sensors it would make sense to do those as well (or just use motion sensors / glass break sensors and save a lot of work).

It also makes sense to run at least a couple wires up into the attic, for a siren or other future use.

What I'm not sure of is motion detectors. What's the best way to leave the wires to be able to hook them up later? Any tricks to avoid cutting a giant hole in the wall later?

Any other considerations to pre-wiring?

When we do drywall, if there's a loose wire (e.g. electrical line for a hard-wired dishwasher), we cut a small hole and pull it through during installation. Pretty easy to do while everything is open and you can see both sides of the drywall. Leave plenty of slack so it can be fished through the drywall before it's been attached to the wall, and the hole can be made even smaller.

The other option is installing a J-box like you would for phone or cable wires, and leave an opening in the drywall like you would for any other J-box.

For other considerations, I'm a huge fan of conduit. No need to go to every door/window, but it wouldn't hurt to run some to where you want the main key pad, to the attic, and to your telecomm connections.


Can EPDM roofing be applied directly over XPS panels? I couldn't find any information if one can put EPDM rubber (ethylene propylene diene monomer) directly over XPS (extruded polystyrene)? The materials are used for hydro and thermo isolation (consequently), thus it's reasonable to cover XPS with EPDM when building a roof. I'm interested mostly if anyone tried to combine them. Were there any problems with their chemical interaction or adhesion? How long such type of covering could exist? The links will be useful too. Thanks in advance.

Always follow the manufacturer’s installation instructions. One of the largest roofing companies is Johns Mansfield (JM).
There’s many considerations including attachment to roof structure, splicing, fitting around vents, conduit, etc. If you use their accessories, fasteners, etc. it’s more likely that the system will be weathertight.
Here’s their product description:
https://www.jm.com/en/commercial-roofing/epdm-roofing-systems/membranes/
Here’s their insulation and cover board options. I don’t see XPS, but I do see a lot of polyisosanurate  options.
https://www.jm.com/en/commercial-roofing/roofing-insulation-and-cover--boards/
As you can see, the insulation comes with an isolation board to isolate it from the membrane. In addition, they recommend Fesco Board to install on the roof deck to isolate the insulation and membrane from the roof structure.


How to evaluate if a door is hung correctly? I do not have experience hanging doors and I would like to understand how to evaluate an installed door replacement.  Any list of good checks / verification is appreciated.  My gut tells me this is a fine art and that there may be a few not so obvious checks that come only with experience.  If you have hung 10+ doors please state this in your reply.

Plumb, level, square.
On plane (not necessarily with respect to the wall, which may be twisted or otherwise distorted).
Uniform, appropriate gaps.
Solid attachment, especially at the hinges and strike plate.
Smooth, quiet operation with no gravity-induced movement.
Proper weather sealing, where appropriate.

Experience claim: Hundreds (thousands?) of interior and exterior doors installed or refurbished over 30 years.