Ground wire pass-through safety switch to sub panel? I have an out-building 150+ feet from the main service panel with its own 240v 60 amp sub panel. It is powered via a four wire bundle going through underground conduit -- 2 x 120v feeders, 1 neutral, 1 ground. This is a sub panel in a detached building so the neutral and ground will not be bonded in the sub panel. The sub panel is on the inside of the building.
There is a Square D D222NRB non-fused 60 amp safety switch installed on the outside and that is what the underground conduit is connected to. The safety switch has two sets of two lugs for the incoming and outgoing feeders, plus a neutral bar to accommodate the in and out neutral.

There are no lugs nor any obvious spot to mount a separate grounding lug or bar for the ground, in the safety switch.
It feels wrong to not bond the ground wire to the safety switch box. I always bond the ground to the box in any metal enclosure I am connecting wire in. The lack of a ground lug and seeming complete lack of even a space to mount a ground lug is throwing me for a loop, though.
Is the ground wire intended to pass through the safety switch on its way to the sub panel?

Look for the grounding symbol stamped into the switch enclosure
There will be a grounding symbol stamped into the switch's enclosure somewhere around the bottom-left corner, as per the wiring diagram.  That symbol marks where the ground bar, a Square-D GTK03 in your case, goes -- there should be a hole and a bump near it.


How to hammer in tight place I have the back of my kitchen sink base unit that has popped out, is made of thin plywood. Now it's raised outside if it's groove and I need to hit it with a rubber mallet to push it down into the slot. My problem is hitting it from the top is not possible as the space is quite tight, I can only raised the hammer about an inch.

Is there such a thing like a elongated 'Z-shape' metal bar that one side of the 'Z' I can hang onto the plywood and then the elongated neck brings the other lip of the 'Z-shape' down where I can comfortably hit it? What would this piece of tool be called if it did exist? Or is there another way around this?

Thanks

No, at least not that I've come across. Sure, you can find bars shaped like that, or make your own, but they're not readily available in tool stores.

Your best bet is probably to try and pry the panel down rather than hitting it with a mallet. Use a flat bar or large screwdriver or other tool along with a block of wood to protect the edge of the panel. Exactly how you do it will depend on the particulars of your situation.

Update: Mazura reminded me about a flooring installer's best friend, the Z-bar. Might do the trick, but at a cost for one little task.


Getting mild electric shocks from tap water if washing machine is switched on My washing machine is placed in my kitchen and whenever it is switched on and working (washing), I get very mild “tingles” from the kitchen's tap water.
I'm in the UK, and I've checked that the wall socket is earthed and the machine's plug is also earthed. I'm not using any extension cables.
What else can I check before calling an electrician? If possible I'd like to fix this problem myself.
Thanks!

EDIT 1: My house was built on the 70s.

EDIT 2: I asked an electrician to fix the problem and he said the following: two of the earth wires were in the correct position but one had no earthing sleeve on it and was pressing on the live wire. The third earth wire was not connected at all and there was a small voltage showing, but not enough to trip the switch. He re-routed all the wires and attached the loose earth wire and all is now fine!

This sounds like a pretty dangerous situation. There are some things you could check.

A. Look into if the earth grounding connection at your house is  good solid connection without corrosion.

B. Try seeing if you get the same tingling effect when you run a different appliance plugged into the same outlet such as a blender or toaster.

C. Check if the outlets near your kitchen sink are protected with GFCI devices.


Does true wireless 3-way switch exist? I currently have a 3-way switch setup which is made up of two 3-way switches to control a hallway light. Due to oversight, an additional (4-way) light switch is much desired in the middle of the hallway.

The cost of opening up the wall and rewiring the 3-way circuit to accommodate a new 4-way switch is prohibitive.

The wiring is new and all the switches have neutral. I am wondering if there exists a wireless switch (looks like a wall switch but without wires behind) that can be used to toggle another 3-way switch over wireless such that I can have a 4-way setup.

I have looked at several products. Many of the so called "wireless 3-way switch set" is really a wireless controlled single pole switch that turns existing single switch into 3-way.

Here is an example of such "fake" 3-way:
https://www.amazon.com/SK-8-Wireless-Anywhere-Lighting-Control/dp/B0052ROEB2

Does it exists a set similar to above but replaces a 3-way switch?

You can get pretty close.

"...looks like a wall switch but without wires behind..." Assuming here that your looking for the standard TOGGLE light switch, then you're not likely going to find the exact product.

If Decora or paddle style wall switch is acceptable, then replace both existing 3 way ends with this or this (the difference is the first is on/off only, the second also Dims- choose the dimmer if the hall light is dimming compatible).

For the middle location choose this wireless switch plus a mounting bracket and any standard Decora or paddle switch wall plate.

Initial set-up (specifically linking) is slightly confusing if you've never before used Insteon products, wiring is however straight-forward.  Insteon (also known as smarthome.com) does have good phone support (although their phone system produces horrible call quality-if that happens ask the support person to call you back as calls in that direction don't seem to be affected).

You also need a standard USB cable and perhaps an adapter to charge the wireless switch. (the middle switch will only need charging a few times a year). Honestly you likely already have this standard USB cable, it's pretty standard and the same used to connect most camera's and non-apple phones to a computer or charger.   (I put smarthome.com links for the last two because those two items appear to cost much more when purchased via amazon.)

Disclaimer: I do NOT work for Insteon/Smarthome.com. I do work for a company that has a sales/installation agreement with Instean/Smarthome.


How can I run power from an end-of-run light switch to a second switch? I currently have a ceiling light that has the power at the light. It is switched with a single pole and both white and black wires are connected to the switch. The white is hot. I take it there is no neutral in this case. I want to gang up a second switch to power a new light in a nearby closet. How do I jump power to the second switch?

Can't be done, without installing more wires.

What you have is known as a "switch loop".  An ungrounded (hot) conductor goes to the switch, and a switched ungrounded (hot) conductor comes back from the switch. There's no grounded (neutral), so no way to extend the circuit.


Is there a problem in adjusting the radiator setting too often? I just brought two small Ethernet-type cards, so I could start a project to control the single radiator in my student accommodation over the internet. (#EngineeringStudent)

Now, the when I came back from my holidays, the valve jammed and it was freezing with 18 degrees (I turned it down manually while I was gone). So....

Are there any obvious problems of getting a motor (servo) to change the radiator setting say, every 6 or 12 hours, automatically according to the temprature? With this previous history, do I run the risk jamming the valve again? It's just a standard thermostat control which I intended to attach the motor to.

Thanks,
Manfred :)

Those are inexpensive mechanical controls.  There's no reason they can't be rotated every few hours.  Doing so, however, is mechanically challenging.  Good luck.  Be sure to decouple your rotor (with a belt or gasket) so it does not place undue mechanical stress on the knob.


How do I renovate these walls to be smooth? My skill level: Complete novice
The walls in my apartment are quite old, and I would like to renovate them and make them smooth and modern, Similar to the walls in this article at The Spruce. (sort of)
I'm guessing the easiest option is to just put up drywall on top of the old wallpaper?
A few things to consider:

Behind the wallpaper the wall is brick and concrete from 1933. Does that pose a problem on how to mount the drywall? Do I need to erect some wall studs for support? If so, how are such studs mounted?
The wallpaper does not go all the way up to the ceiling (see bottom picture), but is cut short by a kind of black thin molding (?) about 20-30 centimeters from the top. I would like to remove that molding and have my new walls go all the way up to the ceiling.
Above the black molding the ceiling does not connect to the wall on a sharp edge. Instead the walls curve outwards slightly (see red arrows in bottom picture).

I have removed similar wallpaper multiple times and if it is like the type I have removed it is actually relatively easy to take off of the wall.    You will simply soak it with a hot water and vinegar combo over and over until it peels off easily.   You may need to soak one area 4-5 times over the course of an hour but you can do everything at the same time so a room should be about 2 hours.
However it leaves behind tons of gook, paper and glue on the walls so you will have to let it fully dry and scrape and sand basically the entire wall.
The trim will pop off.   After that though - depending at what point it was installed and how it was installed - this could be little to no work or a lot of work.   If it were installed on a finished wall it will be a tiny bit of joint compound and sanding.    If it was used to conceal a "gap" for the cove it will be a ton of joint compound and sanding.   Still doable for a novice and really the biggest issue is everything needs to be covered/removed from room when sanding.   The other alternative to the trim is install a more modern trim and it could look nice.
The cove corner....  Whoaaa.   Not worth it at all.   It looks nice in your picture and for you to spend days of work trying to get a 90 degree angle.   Well whatever you think it is worth but if I were renoing a house I would never for one second think about redoing those ceilings.   They look great - it is the trim and wall paper that make it look "old".


Regency gas Fireplace main burner is auto igniting and won't shut off until i turn off gas valve I have regency C34 gas fireplace probably made around 2000. Unit has worked well but recently started itself and would not shut off until I shut the gas off. This has happen every time since when I relight the pilot light...it takes about 30 seconds and the main burner will ignite and not shut off until gas is turned off.
Each time after I turn off the gas value in about 5 seconds I can hear something open/close not sure what.
This unit has an thermostat remote control  and a receiver box which runs on batteries that has an off, remote or on switch. I have removed the batteries from the remote, from the receiver even at different times and after I light the pilot in about 30 seconds the main burner ignites as mentioned above. I have moved the switch on the receiver box to off and the unit will not shut off. Please let me know what the problem could be.

Mark

It sounds as though there is a short in the wiring somewhere.  Most fireplace remotes will still function manually with the batteries removed.  The C34 utilized a SIT millevolt gas valve.  The remote controls' 2 wires will be attached to the valves "TH" terminal & the THTP" terminal (top & bottom terminals). If you remove 1 of the wires & the issue ceases, its a remote problem - & the fireplace is fine.  At 17yrs old, its probably the remote.  The reason that the burner comes on 30 seconds after lighting is because that about how long it takes for the thermopile to generate enough power to energize the valve.  The click you hear shortly after shutting off the gas is the control valve closing from the pilot being shut off - a safety device.


What do fractions mean when talking about electrical wiring When buying extension cords and other types of wiring,I consistently see fractions. I see that it may be a reference to the conduction capabilities of the wire? Please explain. For example:

"Southwire 18/5 thermostat wire"

https://www.amazon.com/Southwire-64169622-Conductor-Thermostat-Power-Limited/dp/B0069F4HHC

It is not a fraction. 18/5 means that there are five (5) conductors and each is 18 AWG (american wire gauge). The gauge relates to the current carrying capacity of each conductor.

It was all specified in the title of the amazon link that you provided:

Southwire 64169622 5 Conductor 18/5 Thermostat Wire, 18-Gauge Solid Copper Class 2 Power-Limited Circuit Cable, 50-Feet, Brown


Why do many concrete blocks have this strange shape on either end? I want to build a simple wall out of concrete blocks and notice some have this strange shape, the ends look like a capital letter "I". As best as I can tell from any picture, this isn't like LEGO, making them snap together.
Why is the shape like that? Is there some advantage to me as a consumer, building a wall, to buy this shape? For instance, will that provide greater strength to the wall?

As with most building materials, there is a balance between strength, weight, cost and other attributes.
Solid concrete blocks would weigh roughly twice as much as these blocks and cost twice as much too. But they wouldn't add that much strength. In addition, the hollow sections make it easy to grip, move and place the blocks, whether by man or machine.
With the blocks stacked in a wall so that the hollow areas are vertical or horizontal, the visible faces of the wall are solid. With the hollow areas vertical, they can be filled with concrete and rebar for additional strength, particularly including anchoring to a foundation: rebar embedded in the slab poking up into where the blocks are placed and then filled with concrete. Here is one example article explaining how to do this.
As far as the "I" shape, that little gap in the middle of each end allows for mortar to hold the blocks together while still having the faces of the wall "just blocks".


5500 Watt / 30 amp generator feeding 5000 Watt 20 amp manual transfer switch I have a manual transfer switch that was installed approximately 10+ years ago that is rated 5000 Watt  and 20 amp max input. The old generator died and was replaced with a Generac GP5500 / 6875 model. Twistlock outlet from generator states 120/240 vac - 30 amp. Wiring to transfer switch is 10 - 3 w/ground  - approximately 60 foot run. Transfer switch has 6 - single pole 15 amp circuits  with two connected together for well pump. Others are for fridge, furnace and lights. Should this transfer switch be upgraded or is it safe to operate?

From the information you have given out on your last comment "maximum 5000W" the answer would be that you need to replace the transfer switch to match the new generator.

Your old transfer switch (xfrs) has a max rating of 5000W and you new generator actually has a surge wattage of 6875W which is considerably more than the existing xfrs rating. We are not taking into consideration what is connected to your current system. It's a matter of how much the generator can provide. In short you size generators to provider a certain amount of power. You use what's connected to calculate the required size not the other way around.

Good luck


How should I put a gutter downspout on a corner of my house surrounded by pavement? I'd like to install gutters on my house to direct water away from the foundation, but one front corner is surrounded by driveway on one side and a paved walkway on the other curving back to the front door with only a narrow mulch bed in between. Unfortunately, I have a front door bump out that interrupts the roof line and makes a continuous gutter run impossible. I'm also in the northeast, so draining to the driveway could create a major ice hazard. I'm rather stumped.

What is the best way to handle a downspout on this corner of the house? Is there any solution that wouldn't involve a major excavation project?

A rain barrel with weep holes drilled in the bottom could provide a buffer to catch sudden rain flows and let the water trickle out over time. It could be above or below ground, though if above ground you could have trouble with it freezing before the water all drains out. Above ground wouldn't be terribly attractive; below ground sounds like too much digging! Also, the barrel has to be sized with consideration for the number of square feet of roof that drains to this point and the depth of rainfall you want to handle. It doesn't take a large roof nor a heavy rain to overflow a 55 gallon drum, for example.

I suggest the DIY horizontal bore as well. (background: I've just completed a 25 foot bore under a driveway and a 3.5 foot bore under a footing in my own yard.) Sandy soil may make the job easier for you -- my soil is pretty heavy in clay and a simple garden hose doesn't dig through it. I'll describe some of the techniques I used in that long bore, but yours will be much easier because it's shorter and has more favorable soil.

Water tightness

Sometimes it's important that a drainage system move all the water away with zero leakage. That doesn't appear to be the case here. I focus on the "limited leaky" approach because it's simpler. Leaky by design allows one to forgo gluing pipe joints and gives more flexibility about the terminations of the pipe.

Consider the grade

In an open ditch water runs strictly down hill. In a pipe, however, water can be forced up hill -  we need only to ensure that the discharge is lower than the source; the discharge doesn't have to be the lowest point in the system. We take advantage of this to route water under a walkway and bring it back up to surface level on the other side.

The drawing illustrates one approach. The downspout pours water into the left standpipe, the connecting pipe across the bottom fills, and the water level rises equally both standpipes. Eventually water spills out of the right-hand standpipe. Water continues to flow from the downspout through the piping system and spills out onto the lawn/soil on the other side of the walkway. There's no need to seal the downspout to the piping. To avoid water spilling out at that joint, simply make the elevation of the left standpipe higher than the one on the right and choose a pipe that's large enough to handle the flow (ie, larger cross-section than the downspout). For small amounts of rainfall the piping may not fill enough to spill over at the outlet end; in this case the piping itself acts as a dry well.

To avoid the connecting pipe remaining always full of water drill drainage holes in the bottom of that pipe or the elbow at the outlet end. Over time after the storm ends the water will drain out through that hole, and if the joints aren't glued together, it'll seep out there too.

Prepare to bore

To prepare for a bore, dig a trench on the lawn side of the walkway to the depth, slope, and direction that you want. Make it at least 2 feet longer than the width of the walkway.

Choose a sturdy pipe for the section going under the walkway. It may be necessary to drive the pipe in with a hammer, so the light weight corrugated or thin wall stuff may not work well. ABS or SCH40 PVC in 3 or 4 inch are great choices. Cut a section of pipe about 1 foot longer than the width of the walkway. For the sections of pipe that aren't under the walkway you can use the rest of the solid pipe and/or lighter or even perforated pipe.

There are basically two approaches for low-buck boring: a cycle of using a hammer to drive the pipe in a few inches further than it was before and pulling it back out to clear the soil from the interior of the pipe, or flush soils out of the bore as you go. I often use a mix of these.

Drive and remove

If the soil will be sticky (ie clay) then lubricate the pipe exterior and several inches of interior. Cooking spray works well. Lay the pipe into the trench ensuring that its slope and direction are appropriate to emerge at the right place and avoid running into the bottom of the walkway. Hold a block of wood to protect the end of the pipe and drive the pipe into the soil with an 8 pound sledge hammer. Firm bumps are all that's needed; it doesn't need to be struck with the same force one would use for breaking concrete.

After the pipe has advanced several inches -- maybe two to six, depending on pipe size and soil type -- pull it all the way back out. A twisting motion can help. It may be necessary to use a pipe wrench or strap wrench to get enough leverage for twisting. Press the core of soils out of the pipe, re-lubricate as needed, and repeat the process.

Flush as you go

Soils can be flushed out in (at least) two ways: running water or vacuum. As the bore diameter becomes larger it becomes easier to use a wet/dry vac to pull soils out of the bore. It may even be possible to drive the pipe in as above, then vacuum the soils out of it rather than pulling the pipe out of the bore.

Usually soils are too heavy to be vacuumed dry. Pressurized water is a great way to erode these soils. In sandier soils it can work to use a garden hose directly, or to adapt the garden hose to a length of metal pipe and push the metal pipe through. If the soil is stable one can erode a tunnel with the water and insert the permanent pipe later. If not, it could be necessary to drive the pipe in to keep pace with the the water erosion.

Some soils (mine) don't respond to garden hose pressure. In these soils a turbo nozzle on a pressure washer does amazing things. The turbo nozzle sprays a 0 degree stream of water in an orbiting pattern making a cone of high pressure spray about 2-3 inches wide.

In a challenging bore like the 25' job I just did it may be advantageous to alternate between the turbo nozzle and the wet/dry vac. The nozzle cuts the soils and makes a slurry, but the water doesn't carry the spoils out of the long bore very well. One can cut a few inches up to a foot of new bore with the turbo nozzle, then pull that out and insert the wet/dry vac (using pipe as an extension) to extract the spoils.

Finishing up

If there's enough slope in the front lawn, it may be possible to cut the pipe on an angle and simply let it emerge from the lawn. Otherwise, put an elbow at the end and use a grate or a pop-up to allow water out but prevent people being injured by stepping into the hole.

On either side of the walkway use perforated pipe, or drill holes through the pipe, so that after the rain has ended the pipe can completely drain. Position the pipe so these holes are on the bottom: this allows water to drain out and prevents soils trickling in, which would soon block the pipe.

It might be necessary to install heat cable to avoid the pipe being filled with ice in winter. This depends on climate -- how cold it gets at the depth the pipe was installed, what kind of sun exposure there is, etc. It's a fairly simple thing to fish heat cable through the downspout and drainage pipe if that should be necessary.


Drywall falling from ceiling I have a problem in my apartment where 2 sheets of drywall are falling from my ceiling, seemingly in the full sheet and in 2 different rooms.  They are coming down in rectangle shapes, with straight edges.  I'm wondering what the cause is, and there are several factors that could come into play here.

The kitchen has 1 sheet that is falling down so that I can move it with a probe, and it seems to be held up on one end by only the joint tape.  The other sheet is in my living room and also looks to be held up on one end by the joint tape.  These 2 sheets are not adjacent, but only about 10-15 feet away from each other.

I live in a fully finished basement apartment that, in the 5 years I've lived there, has not seen any real moisture problems due to being partially below grade.  The end of my apartment seeing the issues is the only end that is even partially below grade, with the bottom of the windows being 50-some inches from the floor.
The people above me play loud music, to the point where the police have been called several times, and one of the officers was heard to say they could hear the music from a block away.  This same family has several kids that run, bang,  and jump around, making a lot of noise, to the point where my walls rattle, even though I only have 1 wall hanging.
The same people living above me had a water leak in their bathroom a couple months ago, causing it to effectively rain in my bathroom.  The water spread into my bedroom (which is right next to the bathroom), causing water to run out of my light fixture there, as well as the light fixture in the hall next to the bathroom.  The kitchen shares a wall with the bathroom and doesn't have any light fixtures near that shared wall.
I don't cook much, but I use a warm mist humidifier in my bedroom.  This is at the far end of my apartment compared to the entry to the kitchen as well as the living room drywall sheet.  The humidifier is under a plastic covered window that doesn't show any moisture.  I've been running the humidifier the past 2 months.
The apartment complex has cockroaches.  I don't see very many of them, but I know the people above me do, and lots of them.  I can hear them walk/stomp around, and the other day I heard them enter the apartment, then start to quickly stomp around above my kitchen, presumably to kill the roaches.  We've had exterminators come twice to spray for them.

As I can fairly easily hear the people above me, I don't believe I have much, if any, insulation in my ceiling.  I can see some dimples in the drywall, which I'm assuming are the screws that have pulled through.  The paint is intact and I only noticed this situation because of shadows on the ceiling.

I want to know so maybe I can avoid this in the future, if I caused this, or have some information for the landlord, if they try to blame me for this and it's not actually my fault.  I don't want to falsely accuse my neighbors, but I wouldn't mind seeing them get kicked out, either.

Are the roaches too many/heavy for the drywall?  Did the flood from above get into the kitchen ceiling, causing it to weaken?  Is it all the noise/banging on the floor above causing this?  Is it the humidifier?  Something else entirely?

Really, it all boils down to: Does anyone have any insight as to what single or combination of the above possibilities could have caused these sheets to become detached?

First, you should let your landlord know ASAP, before the problem gets worse. The ceiling falling down is not your fault. Not reporting it and letting it continue to fall down would be.

Anyway, most of what you've mentioned is probably unrelated. Running a small humidifier is perfectly normal. Cockroaches are not heavy enough to pull down a ceiling (picturing that is pretty gross...). Loud music and tromping around (something all upstairs neighbors seem to enjoy) wouldn't put any stress on your ceiling beyond normal limits.

However, the water leak seems like the culprit -- the water may have damaged the drywall around the screws enough for the screws to pull through the drywall, causing the sheets to come loose. Or, the ceiling may have been installed poorly, with butt joints not fastened to joists and just taped together; such joints would have eventually failed anyway, but the water damage accelerated things.


No neutral kitchen wiring Home built 1975, South Florida.

Adjacent to my kitchen sink is a combo switch controlling a non-GFCI receptacle below the sink for the garbage disposal. Next to it (same box) is another non-GFCI receptacle.  Connected to this one receptacle (spliced together, not in sequence) are 3 more receptacles for the microwave, dishwasher & coffee maker.  The incoming wires are a 14/2 on one breaker and a single 14 (red) on another breaker.  There used to be a fan in the next room converted to a simple light. I believe the red wire is the secondary hot that was once used for the fan. The outgoing wire to the disposal outlet is a 14/2.

Obviously, I would prefer to have GFCI next to my sink. The 3 outlets coming off one is clearly not the best set-up, but I have to work with what I have. :/ I have managed to change the outlet and all 4 outlets do test/trip correctly.

However, that leaves me stumped trying to install a single pole switch for the disposal receptacle below the sink. I have only 1 red line in and no neutral.

Is it possible? If not, do I need to splice a neutral to the neutral from the light in the next room & run it over?

Thank you for your help!

Can't have a loose wire

"14/2" means a black, white and bare wire wrapped in a sheath.  "14/3" is the same except it also has a red wire inside the sheath.

If the red wire is outside the sheath, loose or tacked on, then it cannot be used. At all.  This is a totally improper wiring technique. Cap it with a wire-nut and tape, and push it into the back of the box. At the service panel end, just cut it - it is useless.  Whoever installed it did very bad work, and all the other work in the house should be reviewed against Code.

I know what he was trying to do, but you can't do that - so no point getting into the gory details.

Pigtails are fine

It's fine if circuits are pig-tailed with wire nuts and short lengths of wire to the receptacle.  That is a totally acceptable wiring method.

A workaround: put it all on a single circuit

The simplest thing is simply to wire everything onto a single circuit.  It's not good, it would certainly not meet new-build or remodel standards, but it is better than he had it.

When possible, you should pull at least two more 12 AWG/20A circuits, preferably three, and spread the loads out among them. Then retire the 15A/14AWG circuit, or dedicate it to a single thing such as the refrigerator.

Two ways to GFCI

You can install a GFCI breaker inside the panel.  That will protect everything on that circuit.  You must use a 15A breaker because there is any 14 AWG wire in the circuit.

Or, you can install a GFCI receptacle there at the switch.  You can decide which additional loads you would like to GFCI-protect by attaching them to the LOAD side of the GFCI.  If you put a "hot" on the GFCI LOAD terminal, you must also put its companion "neutral" also.  You may end up with 2 wire-nuts with 2 groups of neutrals: the unprotected and the protected.  If a hot goes through the GFCI and a neutral does not (or vice versa), the GFCI will trip.


Bathroom ventilation system with electric fan tl;dr Why am I prohibited from using electric fan in natural / gravitational ventilation system, if there is an additional 2,5 meter long horizontal pipe between ventilated bathroom and the wall?

Two years ago I have purchased a flat and ordered team to perform general renovation works that included setting up inner walls and building additional electric, water, ventilation etc. installation (initially flat had only external walls and very basic installation and was not ready to move in).
As a part of these works, an additional, inner bathroom (no windows) was added. It was equipped with nearly 2,5 meter long horizontal pipe that goes through pantry room and connects that bathroom with vertical ventilation pipe in wall.

Ventilation system's exit was equipped with electric fan on bathroom side (here fan is removed):

Few days ago, I have received a written request to remove electric fan with the explanation that:
(all cites are my translations from foreign language; please forgive me for any mistakes in wording)

Natural ventilation system is all that is needed for ventilation like that. Flats in houses having natural / gravitational ventilation system are not allowed to have electric fans anywhere within ventilation system.

I have contacted person responsible two years ago for renovation works and the designer of above pictured horizontal pipe and I have got following explanation:

Natural ventilation system works by itself (and shouldn't be supported by electric fans) only if vertical ventilation pipe is placed in any wall that is part of the room being ventilated and exit of ventilation system is attached directly to that vertical ventilation pipe.
In your case there's a 2,5 meter long horizontal pipe that connects ventilation system's exit in your bathroom with vertical ventilation pipe. Electric fan is used in this case to push air that is being removed from the bathroom through that horizontal pipe to actual ventilation system's exit in your main wall. From that point it is ventilated out naturally.
If we remove electric fan in this case, there's a risk that odour will remain in bathroom and the room itself will be poorly ventilated / won't be ventilated at all.

I won't deny that I am a complete newbie to ventilation systems, so I have absolutely no idea which of these statements is correct or closer to true. Can anyone help here?

I can’t answer for the requirements in your country, but in the mainland United Kingdom, it is now a requirement to have a fixed mains powered ventilation fan in bathrooms and shower rooms regardless where these are in the building. This applies to new builds and in some cases, where renovation takes place.

The whole reason for having a fan is to reduce the humidity in the bathroom or shower room in order to reduce condensation.

The relevant UK regulations are outlined in the ‘Building Regulations Document F’

I presume there are similar regulations in your country.

I hope this helps.


Can I use a three wire cable to feed a whirlpool tub? If I'm required to add 2 dedicated GFCI circuits for a whirlpool tub and inline heater, can I run 3 wire cable (red,black,white,ground) or do I need 2-2 wire cables?

As long as the circuits are 120V you can run a 3-waire cable. The only caveat is that you would then need to use a two-pole GFI breaker to protect the circuits.

With two 2-wire circuits and single-pole GFI breaker (or devices) you can isolate the circuit for troubleshooting and maintenance.


Replacing R7 in exterior home walls I really appreciate all the great feedback from the forum members on various questions.

We are working on lots of renovations to our home that is located in Toronto, Canada. It was built in the early 70s and the external walls are built 2x4 studs with Gyproc sheathing, 1/2" air gap and 4" brick veneer. On the inside there is 1/2" drywall, no vapour barrier and R7 fiberglass insulation with kraft paper facing. Pictures included below.

We needed to open many of the exterior walls for the renos but not all. However it appears that R7 is no longer adequate in terms of insulation so we bit the bullet and asked the contractor to open up all exterior walls to replace insulation everywhere.

What insulation should we be replacing with? Some of the insulation that was removed from walls has black markings. Is this of concern or point to a possible issue?

Any pointers from the experts would be very helpful.
Thanks

The black is dust that is deposited by air leaks.

The best building framework is passive house and the perfect wall which orders your priorities.   The first is liquid water, the seconds is air, the third is vapor and the last is insulation.

If you've gone to the trouble to open all the exterior walls to increase your insulation, I am going to assume that budget isn't the top priority.

I'd get aerobarrier to give you a quote for air sealing.  https://aerobarrier.net

Once it was airsealed.  I'd go with roxul for insulation.  A passive house membrane like intello on the warm side of the insulation for moisture barrier.  Then drywall like normal.

Big project, good luck !


48AMP kiln on 60 AMP breaker *must be* direct wired in Canada? I am trying to find out what part of the Canadian electrical code requires that the 48AMP kiln, on a 60AMP breaker requires that it must be direct wired, instead of using the NEMA 6-50 receptacle permitted in USA. I would like my kiln to be mobile, and wonder if there is a work around of some kind.

I never found the answer to the specific question "what part of the code", but I did speak with some electricians who indicated that if the kiln were permanently installed it would be considered a 'continuous load', similar to a 'heating appliance' like a stove or a furnace.
However, my kiln is on wheels which I use to roll it into the corner when not in use. As such, the electrician said it is a temporary appliance that should not be direct wired. As such he installed a 60 amp breaker and the correct receptacle for the plug on the kiln (6-50), and a switch inline between the two. He indicated it is safer to turn the plug off first and then remove the plug instead of pulling the plug with 240V at 50 amps available.


Can I pull a c-wire from a second nearby thermostat? I have a thermostat that controls the AC/Heat upstairs which is located on my bedroom wall. Right below that I have another Millivolt thermostat for the gas fireplace in my bedroom. If I want to upgrade the fireplace thermostat to a smart wifi that needed a c wire can I pull the 24 volts from the other thermostat? Thanks

No, same as any electrical circuit, you need a two way street on the same circuit and the c wire is only one of those lanes. The R wire is the second lane (most cases). Additionally, you risk frying your furnace's circuit board, and your fireplace blower still needs switching that converts back to millivolt.
Your solution is to pull from a transformer (install a low voltage power supply of some kind) and provide an appropriate switch relay.
See here:

Can I share "C" wire on two thermostats?
https://www.google.com/amp/s/www.instructables.com/Nest-Thermostat-With-Gas-Fireplace-or-Other-Milliv/%3famp_page=true


Old box of fridge Arm and Hammer baking soda I have an old box of baking soda from the fridge. Now, a couple of home repair folks told me I can just dump it into my kitchen drain to keep the drain clear and deodorizer to get rid of it. Is this true? And if so, can someone tell me what the steps are to do it properly? I am a first time owner and don't know much to be honest. Thanks in advance for any guidance!

baking soda dumped in the sink drain with a little water or down the toilet and flushed would not hurt your plumbing it will dissolve as water mixes with it.


How can I stiffen the subfloor of an upstairs bathroom? I have been doing polished concrete throughout my house.  My wife loves it more than I thought she would and now wants me to do it upstairs.  I am afraid that the subfloor flexes too much, which wasn't a problem on the slab.

I don't want to put down anything too thick over it or the profile will be too much against the adjacent carpet.  What is the thinnest way to stiffen the floor?  I am going to use lathe so I don't really care about the cement board.  I just want to get the flex out.

There are two choices to stiffen a floor system

Halve joist span with a beam.
The beam-in-joist method has the advantage of minimal final impact on the room below.  It does mean spanning the beam to a load bearing walls.
Double up joists in area.
This requires removing floor or ceiling to sister existing joists. The joists also have to span as far as the existing joists.

The beam-in-joist solution should be confirmed with a building plan review for point load considerations under the transferred supports.

Update: I did come across a very thorough article from Fine Homebuilding "6 Ways to Stiffen a Bouncy Floor". (its a .pdf file)

Could I suggest a roll or 2 of Ditra (Schluter) under some nice tile?


fireproof corner in basement? My hillside house's outside walls are made of fireproof rastra and there is an occasional possibility of wildfire in the area.  There is a crawlspace with dirt floor.  We would like to build under the house in a corner where we have 6 feet plus vertical clearance to make a fireproof storage for valuables, not permanent storage but just during fire season.  Would cinder blocks work?  What about floor and ceiling?

We often design and build “safe rooms” in custom homes. Safe rooms have several requirements: 1) structurally secure, 2) fire protection, 3) temperature and humidity control,
You are requesting information about fire protection only. However, it might be important to have a space that can protect you structurally in case of a severe wildfire AND keep documents in good condition year round.

Structurally, reinforced concrete block is an excellent choice for walls, but you’ll need a suitable ceiling. I’d recommend a “heavy timber” ceiling covered with several layers of gypsum board or a structural concrete slab.

Fire protection is based on “hours of protection”. That is to say, all materials are given a fire rating depending how long you need to keep a space safe. The Code requires a 1-hour rating between the garage and a home, which is about how long it takes to get everyone and everything important out safely. I’d recommend 4-hour protection, but you can’t obtain a 4-hour rating with wood framing. (You’ll need concrete block and/or concrete.)

You can buy fire doors that have fire ratings too.

If you add a duct into your new fireproof space, you’ll need to install a fire damper that shuts off during a fire. Very common, but you’ll need other means of oxygen if you plan on having the room being a place of rescue.

Floor construction is less important, but using a non-combustible material like a 4” concrete slab on grade would be appropriate. (Make sure ground water and water table is accounted for and the area is adequately drained with a french drain.)
Depending on where you live, access to fire protection, etc. will help you decide how secure and how much fire resistance is required.


On which hinge(s) should hinge pin doorstops be installed? My solid doors have three hinges. On some of them I need to use hinge pin stops.
On which hinge(s) should doorstops be installed?

I do not know if there is a "should".
I have always seen them on the top hinge, probably because it does not require bending over to install.
If you have a middle hinge that may be better as there will be less flexing of the door.
You have solid doors but I have seen them punch holes in hollow core doors.
I avoid them if i can, they can cause stress on  doors, trim and hinges- loosening/stripping hinge screws. I prefer baseboard or even floor mounted stops.


Can I use a PVC cleanout plug in a Cast Iron Cleanout? There's a cleanout plug on this pipe that I simply can't get loose. I've tried liquid wrench, PB blaster, heating up the area with a torch, everything I can think of. All that's really left is to go after the plug with a drill and a saw and just pull it apart. However, none of my local hardware stores HAVE any 4 inch cast iron, all they have is PVC. Can I put a PVC cleanout plug in a Cast Iron cleanout?

Another option would be to cut the pipe above and below the cleanout, and install a PVC Y-fitting with a cleanout cap using no-hub couplings like these:

I would think that drilling and/or sawing out the old cast iron cap is going to be a giant pain in the rear, and will be likely to damage the cleanout fitting to the point where it needs to be replaced anyway.

Make sure your cast iron stack is supported above before you cut it.


something similar to zip ties? (heavy duty) I have a dog kennel and framed roof with a tarp.

Traditional bungee straps for the tarp have too much give and stretch out over time. Additionally, any snow load causes the tarp to deform and dump snow into the kennel.

I tried 150lb tensile strength zip ties to keep the tarp taught, however these don't seem strong enough as I keep finding some on the ground from snapping in the cold.

Is there a either a much stronger zip tie (250lb tensile strength) or an alternative to attaching the tarp to the roof frame?

250lb cable ties are made, yes. "industrial zip ties" seemed to be a pretty good search string for finding sources.

Probably more the cold making the plastic brittle than the basic strength of the zip tie. They do make "large, industrial" zip ties (I've seen 3 feet long and half an inch wide, and they probably go bigger) but you'll probably get better cost and service from rope, and learning to tie a "trucker's hitch."


Garage roller shutter door opening by itself It has a remote control switch and brand is Centurion Australia.
I closed but it opens by itself after few hours.

I recently tried to add a duplicate remote key but that was incompatible and so the coding failed. Initially I thought it was due to that, so removed the batteries from it . But this also doesn't fix the issue

Any ideas?? Thanks

I was not fully aware what happened when I tried to code an incompatible remote key bought for spare from Ebay..

What I did is changed the existing code and that seems fixed the issue. I have to copy this new code to all the existing keys, but that was easy.

This video also helped..


Air conditioner venting What about venting a portable air condtioner into the cold air return of the furnace? Good idea or not? Trying not to go through a waal and no window access Thanks

No do not do this! The cold air return of the furnace goes into the house. You cannot vent a portable a/c into the space being cooled. It may seem to work for a while but will inject more heat into the space than the a/c removes.


Which screw and anchor should I use to mount a projector screen? I have a projector screen which weighs about 8 kg (~17.6 lbs) and to light it up a little for when I don't use it I decided to mount a LED strip behind it. I already bought matching strips of wood (24 mm / ~0.9 inches). The screw head has to leave a space of about 2 mm (~1/10 inch) so that I can hook the projector screen.

The wall is no drywall, I suppose it is out of concrete or bricks. I've only put nails in it and I think I won't get them out if I have to...

The projector screen frame has two mounting holes in both top corners.

Which length and diameter should the screws have? Maximum diameter of the mounting holes is 11 mm (~0.4 inches)

The screw should penetrate at least 1", more if possible into the material (concrete, brick, etc.).  So if you have 24mm thick wood, and you want the screw to hit a depth of  say 1.25" inch, you need ~24mm+32mm (1.25") +2mm (exposed screw) = 64mm (2 1/2") screws.

Now you need a plug or anchor that can accept this length of screw. As for size of screw, I'd use a #6 or #8 screw.

Another (easier IMO) option is to use a concrete screw that does not require an anchor - they are sometimes known as Tapcon's (common North American brand).

Make sure to drill the hole at least 1/4 deeper then needed.


After replacing a 1-gang electrical box with a 3-gang box, am I allowed use the same 1-gang wallplate and drywall over the rest of the box? I need to increase the cu/in (inner space) of a switch.
So I'll switch from 1 gang to 3 gang, and place the switch back in.

After replacing a 1-gang electrical box with a 3-gang box, am I allowed use the same 1-gang wallplate and drywall over the rest of the box?

Basically It would cover with drywall, the other 2 "gangs".
(I would have to recess it in more, and use longer screws)

No, you can't box a box in like that!

When you have a multigang box, all the innards need to be accessible without removing any building finish, as per NEC 314.29, so that the next bloke who services the thing can get at all the stuff inside.  Your choices are to either use a 3-gang to 1-gang mudring (as was linked in the comments), or to use a 3-gang cover that has blank spaces (i.e. no switch or receptacle openings) in the other gangs.


Will showering with the fan on and bathroom door open prevent mold? I have a room mate who loves to just sit in the shower tub with the shower raining over him. He sits in the shower for 2 hours or longer easily (not over exaggerated), just watching youtube videos. He's also taking steam showers. He showers very very hot, producing a lot of steam and causing water to literally drip down the drywall.
The fan in the bathroom simply cant work that hard and suck up all the moisture fast enough. I have told him many many times to take a bath instead because we're guaranteed getting mold development, but he gives me an excuse that he prefers the rain showers.
If the bathroom fan is on AND the bathroom door is open, keeping the temperature in the bathroom cooler, does that resolve the moisture/mold problem? Or are you guaranteed getting mold no matter what if you steam shower and shower that long?
I am also not sure if leaving the bathroom door open would be a good idea, potentially having the moist air going outside of the bathroom as well.
We constantly argue over this and we're both adults so I can't really do much to him in terms of treating him like a child and shutting off the main water supply or something like that so I'm really looking for a second opinion that I can show him.
A compromise would also work,  such as a fan on AND bathroom door open. If that's the golden solution to prevent mold with long steam showers then that's acceptable for me as well. He is paying for the extra heat and water charges anyway. I just don't want mold in this still brand new house.

A you hear all of the time mold needs moisture to get moving.
But, it also needs time, and a food source.
The Drywall and most surfaces give it that food source, but the time and moisture you can control.
If the house is new, the fan should be fit to size. I say this, but sadly it's often not true. Also, if the roommate likes steamy shower rooms, a good fan and an open door will likely remove the "steam room like" environment.
So, my opinion-ated answer based on these thoughts & some known facts:
Fan & venting:

Ensure the fan is the right size for the room. Please see what it is rated at, increase it to a higher cfm fan if need be.
Check the vent tubing, it should be rigid, not ribbed flexible like most contractors and builders, and homeowners use.
The shorter and straighter the run for the vent tubing, the better. Use 6" vs. 4" even. Also, make sure it is properly supported as moisture has to get out asap! this is the key really. It might be full of water, make sure it is not obstructed

The walls, cracks and crevices are where mold will grow, so a circulation fan in conjunction with the vent fan is a good idea. The home will need a source of fresh air or circulating it in the living space works, but is worse. Your best bet is to get it out of the house. A fresh source, (even opening a window a crack will suffice).
After the shower, wipe the walls down, keep the vent fan running for a while. you can install a timer too to control it and not have it run 24/7 (although that might be what you will need).
The sooner you keep the surface dry, the mold wont grow.


Best way to mount a floating L-shaped desk to a brick wall I'm in the planning stages of building a new corner desk. I've started by measuring the corner of the room and planning the size, but I'm not sure what's the best way to mount it right now..

These are some sketchup renders of walls, desk, pc, monitors:

Desk details

Width of L two legs: 60cm (23.622")
length of L the two legs: 272cm and 162cm  (107" and 63")
material of the desk: 3 to 6 cm of plywood (1" to 2.5")
monitors will be wall-mounted

Another way of building the desk is using 1cm (or 1.5cm) pipe (round or square, not sure yet), and place a 1.5cm layer of plywood over that.

Mounting surface details:

the walls are brick (around 30cm / 11.8") with some hollow spaces in them
the corner behind the monitors is a load-bearing, concrete with rebar
(hope that is the right term of concrete with huge steel beams in it)
the right wall has a window with an inside ledge
above the window is also a load-bearing beam made of concrete with
rebar

I was thinking of mounting two pieces of wood or metal to the walls, to create a lip the desk can rest on and a few L-shaped metal pieces that will hold the desk and prevent it from warping.

Am I on the right track?
Thank you!

Reading from other comments here - 1cm round or 1cm square pipe just sticking straight out of the wall on its own will not cut the mustard. You should be thinking of some type of right angle support bracket. With a 60cm side shelf, supported along the wall on a solidly mounted strip, that right angle bracket should come out under the shelf to at least 50cm and have a vertical side against the wall as far down as feasible. I would think that the vertical span of the bracket should be at least 20cm. The length of the third side of the triangular bracket would best be if it was full length but if the vertical and horizontal sides of the bracket were really sturdy then the angled side could be shorter.

Brackets like this could be purchased ready made or fabricated out of wood or metal.

Note that with brackets like this a good share of downward applied force at the outer edge of the shelf will get translated to pull out force on the mounting strip and the upper fasteners on the bracket edge against the wall. You will have to make sure to use fasteners into the brick that can withstand this pullout force with a good margin of safety to ensure that the shelf is secure. You should definitely be thinking in terms of someone coming along and trying to sit on the edge of the desk even is that is never the intention.


What is the standard distance between a table and a banquette? We just moved into a new condo that has a small area (43"x120") off the kitchen that I am thinking of converting to a dining nook with a narrow table. Considering the dimensions, it seems inappropriate to put chairs on the long side that is against the back wall, so I was thinking a banquette on 2 sides (one short, one long), to create a restaurant-style booth.

I have figured out the size of the banquette (18" wide seat, slightly angled with the back at 95° to the seat, giving me an approximate width of 22"), but to know how wide I can make the table, I need to figure out the proper spacing between a fixed banquette and a table. What is the standard for that?

My interior decorator recommended about 1 meter. Also, a good tip is to put newspaper on the floor where you're thinking to put your furniture to get a better visual effect. Get the newspaper on the floor in the right position and then measure.


why does my workbench twist? I'm new to woodworking and recently built a simple workbench.

The tabletop is made of 3x6 lengths glued & screwed together, and I made a frame from 2x2 with a shelf at the bottom. The legs are fairly tall at 90cm. Everything is fixed using screws, atleast 2 for each join, and steel brackets also.

When I assembled everything I noticed that there is a fair bit of movement if you grab the tabletop on either end and twist it, I'm looking for ways to minimise this movement and also find out what I could do better next time.

My suspicion is that I've used wood that's too small / weak for the frame, but it seems very sturdy otherwise. What could I do to salvage this frame?

Note - since these pics were taken, I've also added 2" steel corner brackets to the insides of the corners at the top. This didn't seem to help with the movement much. Also, that janky support at the bottom front for the shelf has been redone, looked awful.

Triangulation is the answer here. The flex and twisting that you see is due to the fact that the rectangles formed by the legs, top and shelf supports are able to parallelogram easily. The long lever arms of the legs are easily able to distort the joints you created even with two screws.

There are a number of methods you could use to correct the problems.

You could use more of the 2x2 material to create angle members from one top corner of each of the rectangles to the opposite bottom corner. If properly secured at the ends the angle member can resist the racking that is currently happening. One angle member works for racking in both directions because the 2x2 material can work up in both a compression mode and an extension pull mode. You may want to avoid adding an angle brace across the front because it would impede the use of the shelf even though it would add additional bracing to the table.
You could cover some of the rectangle surfaces with a thin sheet material like plywood, Masonite  or OSB. This would significantly reduce any racking that occurs in that rectangle. Of course you have to attach this material at multiple points around its periphery. Material on the back and sides should be more than sufficient. One suggestion would be to use peg board material for these sides as you could utilize those surfaces for hanging things.
Another solution that can be used is to use thin steel banding material to create the triangulation. Since such material is only effective in an extension stress mode you would need to apply two such bands on each rectangle surface as a large X across the corners. This material is often available in a roll that has holes at regular intervals along its length (a.k.a, plumbers strapping) that could be very easy to add to your existing structure by using short screws to attach it to the wood members in each corner.

With any of these ideas you want to make sure to use a framing square to ensure that the leg structures are at right angles to the top before securing the braces, panels or banding.


How to ground a 3 prong outlet in plastic box no green ground wire I have a 1954 two-story Pacemaker trailer. It's been rewired by somebody but the receptacles are in plastic boxes. Some have ground wires, some do not.

PG&E is going to give me a refrigerator, but my receptacle is not grounded so they can't give it to me until I ground it. However the outlet box is plastic not metal. There is no green wire anywhere. It's a 3 prong outlet, but has no ground.

How do I get around this so I can get a new refrigerator? Thanks so much.

Years ago I bought an older trailer like this.

All the outlets were 2-wire.  Fortunately, all the runs back to the fuse box were fairly short.  Back in the days when it was built it was assumed that all the neutrals would be connected to a ground bus in the box.

So we made sure they were bonded and attached to a utility company-provided ground rod.

We had to replace all the receptacles with 3-prong outlets.  I stopped short of tying the ground to the neutral at the outlet, which meant that the ground leads ended up floating.

I understand PG&E's position, since they deal with the code as it exists today.

So you have the option of adding a ground lead for the particular outlet they will inspect and call it a day.  Or, perhaps you want to provide grounds all around the unit.

I live in PG&E territory and find they are very safety-oriented.  If their focus is just on that one fridge then adding a ground wire might be worth the effort.

Ground wires do not need to be insulated or run in conduit, but definitely run it all the way to an approved ground bus or rod.

Never rely on the structure itself to be grounded properly.  It is sitting on rubber wheels, remember, and even if it is grounded at the box it would provide a much higher resistance path to ground than a run of copper wire can. Just think of how many structural panels are screwed together between the box and your outlet.  Each one rusts over time.  You get the picture.

Of all appliances I have owned, the one most prone to having a hot case seems to be refrigerators.  So whether you get it from them or buy one on your own, you really should have a grounded outlet for it.

Good luck!


Why do LED lights get brighter when adding additional lights to the dimmer circuit? I just installed new recessed lighting in my finished basement, wiring 4 fixtures with dimmable led bulbs to a dimmer switch. Additionally, 2 of the fixtures are on their own standard switch after the dimmer so that I can turn off half the lights on the dimmer circuit when desired.

Everything works as intended but I have noticed a strange phenomenon. Starting with the secondary switch off so only two lights are on, and the dimmer switch is on a low setting, if I turn on the second set of lights, the lights that were on originally get noticeably brighter when turning on the second set, and then all 4 are at the same brightness.

Does the effectiveness of a dimmer switch reduce when more lights are added in parallel to the dimmer circuit? The answer seems to be yes, but why?

Because LED dimming is a black art

Original dimming was designed for incandescent bulbs.  In fact, most dimmers count on incandescent bulbs, because they leak power through the bulb to power themselves, and this takes advantage of an oddness in incandescents that they are practically a dead short when unlit.

Here's how dimming works. The first one (autotransformer) is also called a variac, and those are huge, heavy and expensive. So dimmers use silicon switching technology (a primitive kind that was possible in the 1960s). These use every trick to provide dimming optimized for AC incandescents.

Most LEDs use switching technology in their internal power supplies.  Switching supplies consider dimming to be a power defect which they try to correct, and they draw more power while it's on to sustain the light while it's off.  In other words, they're pretty good at defeating dimmers.

So how does one dim an LED? The LED has to actually "listen" to the incoming power, reverse-engineer what the dimmer is trying to do, and set LED brightness accordingly.  It's quite a little trick.

But did I mention dimmers are optimized for simple and cheap, and are powered through the light bulb?  Well, when you change the number of light bulbs, you change the impedance of the light bulbs the dimmer is working with.  Since it's relying on that flow-through, I'm not surprised that changes its brightness.

There's better LED dimming

There are several schemes for dimming things generally: 0-10V dimmer control comes to mind.  However, LEDs (the emitter not the screw-in incandescent replacement) are well suited for another dimming method: PWM.  Both methods do not care how many lights are on the circuit. However they require new fixtures.  You can't do either one with screw-in Edison sockets.  And why would you? The LED emitter will outlive the fixture, so why does it need to be changeable?


recessed led worked fine for 3 months but today turned on today and its blinking on and off; not on a dimmer and not using a 3-way switch help. For the past 3 months my recessed kitchen light has worked fine. Controlled by standard switch. Not a dimmer and not a 3-way switch. Today I turn on and started blinking on and off about 1 sec each. Not related to any other appliances coming on and off. No changes to house electrical recently. There is no insulation around the light either. The light fixture/unit cost about $70 from home depot. It screwed into the old can light socket for easy install.

I left it off a few days and even removed and tested on anther circuit but same blinking problem. Took back to HD given replacement...defective device. Thanks for your suggestions however.


Replace radiator mains and reduce electrical consumption I have recently converted from oil to gas in my 2500 sqft 1930s era Home. We have a hot water radiator system. We left the original radiator main pipes and risers. They are large pipes 3” mains. and as such the plumber used a rather large 1/8 HP pump model taco 0011-f4. We would like to move to three zones in the House, and also lower the electricity usage of the system. That pump uses 202 watts while running.  I can’t seem to find information about how to size the main pipes and how that relates to pump size.

1> install a constant delta-P pump ERP rated circulator (it'll adjust the power to the required delta-P instead of running fixed RPM)

2> install constant-delta-P thermostatic preregulation valves (Caleffi Dynamical)

3> Calculate each valve maximum flow allow no more than the needed flow to heat each room

This configuration can let your (GAS) consumption go down by at least 10% if you have a condensing boiler and you set properly the delta-T, also can push down the electric consumption by about 40% or more (up to 95%), (Pump will run maximum just for the first hours, when valves start to throttle down radiator flow, pump 'reads' less need and slows down it's speed accordingly, pumps are also  'intrinsically' much more energy efficient (EEI<0,23 when older 'A-class' had EEI of about 0,40)

Similar configuration may be achived (knowing diameters and lenght of each pipe) using delta-p compensation before zone valves and using 'standard' preregulation valves on radiators (But in this case, calculating each valve is much more difficult, with dynamical calculation is quite easy)

This is a reference for dynamical (it's in Italian, but I think google can help translating)
Another reference (see summary: blue box on page 29)
ERP-related (1)
 ERP-related (2) information (English)


How can I attach a light fixture to plasterboard? After some water damage and a ceiling repair I cannot locate the joist to refix the light fitting. It is a circular fluorescent light weighing about 3 and a half pounds.

Is it safe to fix all 3 screws using plastic plasterboard plugs or should I keep making holes until I find the joist so at least 1 screw is in wood?

In the US, a ceiling lighting fixture generally is mounted to an electrical box. The box is usually firmly mounted to a joist or other structural support.

Most fixtures have screw holes that align with the standard spacing on the fixture box.

In some cases, where boxes need to be suported between strucutral members, they use metal braces that reach to structural members.  The box then attaches to the support bar.

A circular fixture is usually light enough to be supported by the screws into a well mounted ceiling fixture box. If you are replacing the box, a fan type box has extra strength and long screws to support the weight of a fan.
.

They are also available with extra strong braces that fit between framing members.

If the fixture is too large to be supported by the fixture box alone, you can use conventional attachment mechanisms to support the fixture in the ceiling. Screwing into framing members (e.g., joists) is preferred, but toggle bolts or other expanding drywall anchors can be used.

I would avoid plastic anchors because they are the weakest of the options, especially when the weight of the unit pulls perpendicular to the surface rather than parallel to it. See a discussion of anchors here.


Submersible water pump relay question Regarding -submersible residential style water pump relays- pumps fitted with a three wire cable which terminates into a submersible pump relay box--the red wire feeds the starting winding in the pump motor.

I understand the orange wire coming from the capacitor feeds across the relay contact, down the red wire to the starting winding. After the pump motor starts the contact drops out.

The ?-- Do those submersible pumps have drop out clutches or the like that fault the 'red wire starting feed' to the pump well casing, after motor starts, perhaps?  I understand that would be an induced 'ground fault'of the sorts but it would be momentary and would create that difference of potential to allow relay to drop out contact.  Attempting to understand what happens down at the motor, that creates that difference of potential needed for the yellow hot, to feed through the coil?

As far as I know, all the switching for these is done at the control box. Rather than a centrifugal switch, I believe the relay is simply a fixed time-delay contact.

But I consider them archaic these days - For single-phase supply, I buy 2-wire pumps, and would replace any 3 wire pump with a 2-wire pump when the 3-wire pump stopped working. The arguments in favor of 3-wire have become much like arguments in favor of a buggy-whip to make your automobile go faster...

If 3-phase supply is available that's a whole different animal, but it's uncommon for residential applications where I live.


BathroomExhaust fans run continously? How much energy is wasted for the continuous operation of two bathroom exhaust fans?

Why are the wired this way?

I suppose it's at least half an answer, so moving from comments:
If the fans are wired to run that way your house may well be built to a high standard of air-sealing, and the fans running (possibly with a heat recovery ventilator involved) may be an important part of maintaining good indoor air quality - at which point the power to run them is not a "waste" and the heat/cold required to adjust the air they replace is far less than that required in an older house with random air leaks.
In that case, turning them off may cause major indoor air quality problems.
The above is the only case I'm aware of where bathroom fans are set to run continuously as a deliberate design part of the HVAC.
A mechanical vetilation requirement evidently was integrated into IRC circa 2012
As for the other half of the question, the linked document notes a minimum efficency for bathroom fans of 2.8 cfm/watt and a maximum ventilation rate for them of 90 cfm, leading to a maximum power draw (per fan) of 32 watts, or roughly 282 kwh/year. Or it could be as low as 31 kwh/year for the minimum sized bathroom fan (10 cfm) or even lower if the fan is more efficient than the minimum required efficiency.


Why is my timer tripping the breaker on my pool filters power cable? I just bought a pop-up pool for my kids, got it up, running, and all the chemical levels correct.... now i just have one problem: When the timer I bought to regulate when the filter runs turns off, it also trips the breaker/GFCI (not really sure what its called, but there is a red reset and a yellow test button) on the end of the pool filter power cable. Why is this happening?

Switching GFCIs line-side tends to make them a bit cross

Plug-type GFCI devices revert to the "tripped" state when unpowered, unlike receptacle-type designs, which mechanically latch in both "tripped" and "untripped" states.  This was done to allow them to protect against an open neutral, which'd otherwise defeat the GFCI protection and make it impossible for it to trip.

However, this makes them incompatible with being switched on the line side, as you see here.  The solution is to move the GFCI protection to a location upstream of the timer -- GFCI breakers are ideal here, but a receptacle or deadfront GFCI can be used upstream of wherever the switch or timer is.  Once you've done this, you'll have to remove the GFCI plug from the end of the plug-in pool's cord and replace it with a regular plug, with a big note on it saying "FOR USE IN GFCI PROTECTED OUTLETS ONLY".

Either that, or you can remove the plug and wire it into a timer that's then wired in series with another length of appropriate cordage that is terminated in the existing GFCI plug, effectively moving the existing GFCI upstream of the timer...


Light fixture box has 3 sets of wires and I’m confused I took out a light fixture in the basement with the intent of installing a new one which ive done before and I come across 3 sets of wires (3 black, 3 white, and 3 ground wires) i didn’t take a pic or mental note of how it was wired to the old fixture and now I’m confused. Every time I turn the switch on the breaker trips

So your box has only 3 cables. That means it's most likely wired up like this

Incoming cable from the previous fixture or circuit breaker
Outgoing cable to the next fixture
Cable to the light switch (looks like this might be the blue cable)

It looks like you nutted the wires all together. So somewhere in there you have a hot and a switched hot. When you flip your switch, you're creating a bridge between the hot and neutral, and thus your circuit breaker trips because you hit that max amperage instantly.

The good news here is that you can see the cables and where they go. What you need to do is follow the cables and label them. Then we're going to modify the box as such

Connect all the bare ground wires together and nut them off. Add your fixture ground into this.
Connect the incoming and outgoing white wires together with the white wire from your fixture and nut them off (very important the white wire to your switch is not in here)
Connect the incoming and outgoing black wires AND the white wire from your switch. Use a black sharpie to mark that white wire so it's clear that it is a hot wire. Nut them off
Connect the black wire from your switch (last wire left) to your fixture's black wire. Nut them off.

This will correct the problem of your breaker popping when you flip the switch


How *environmentally* durable are pet-resistant screens? I've got some damaged wire screens on our porch, and since I have two dogs I've been replacing them with pet-resistant screens made from what appears to be a nylon mesh coated with plastic/rubber.

So far, they seem to work great. They are physically quite durable due to the fact that they stretch some when the dogs jump on them, and this little bit of give keeps them from easily getting holes punched in them.

However, rubbers and plastics can be prone to photodegradation, and my porch screens are in direct sunlight for most of the day. Does anyone have any experience/knowledge of how durable pet-resistant screens are from an environmental standpoint? How long can I typically expect them to last before they start to break down due to the elements (mainly sun)?

They are typically made of vinyl. Some people are stating here that it last them about 5 years so far. I'd expect 5-10 years. After 10 years, it probably will be brittle anyways. Just keep the chemicals away and wash with water only.


What is the best type of paint to paint a shipping container? Looked for a better stack exchange forum to post this on but did not find one. Looking at buying a used shipping container. The guy who is delivering will paint it but he uses latex. I'm wondering what type of paint is best on a shipping container, and if you can paint that directly over the shipping container, or if you need to prime the entire thing first.

Nononono! Tell him to save his latex paint!

I sometimes paint things at industrial sites.  Latex works fine on the buildings, but when it is used on steelwork of any kind, it turns into an unmitigated disaster, that you pay for for decades.

This is a metal thing left outdoors.  It will have much higher extremes of temperature than a house's walls.  It will also have thermal expansion unlike a house.  There is also an adhesion issue with the { oil-base, possibly LPU } paint that was applied in the factory (in east Asia where nobody cares about enviro regs).

Latex has managed to win on architecture because it's been engineered for 50 years to be a good fit.  Other than that, the only reason anyone even has a conversation about waterborne paints is to "spare the air".  But it doesn't spare the air to paint a bodge job that fails, is reapplied shortcut style, fails again and ultimately must use harsh chemicals to totally remove for a proper coat. That's like those early "low flow" toilets you had to flush 5 times.

The greenest thing you can do is lay down paint that will last.   Here's how:

Given this thing's long saltwater career, I would hose it down good and plenty while giving it a good old "carwash" style wash.  Salt also contaminates paint.
Remove any identifiable rust either with a wire wheel or sandblast down to SSPC-SP10 near-white metal.  Get primer on it ASAP.  See below.
"Scuff sand" every surface you want the paint to not fail. (I.e. Every surface). Scuff sanding means knocking the gloss of the previous layer, to create microscopic "jagged mountains" for the new primer/paint to lock in to.   Anywhere you blow through to bare metal, prime soon.
wash off all contaminants, by optional carwash style washing, then solvent wipedown - the latter preferably the 2-cloth method.  Straight paint thinner is the classic, but they make low-VOC versions for Spare the Air territories that are terrible paint reducer but a fine wipedown solvent. You don't want soap residue or mineral residue from your city water (yes, it has minerals; if it didn't, it would leach them from pipes).
Prime anywhere bare metal is exposed, e.g. Where you removed rust or scuff-sand blew through on any corners etc.  Sandblast or blow-through is excellent "prep" and you can use all sorts of primers.  Wire-wheel is less effective prep, and there, use an excellent over-rust primer such as ordinary Rustoleum 7769.

Don't turn your back on bare metal.  It will rust in a couple of hours and compromise your primer's performance.

If your topcoat requires a compatible primer, or if you're worried about topcoat compatibility, then you prime the entire container.  For instance, I like LPU topcoats, but they require a barrier coat of epoxy primer underneath.
Finally, your topcoat:  Normally I roll-and-tip because I hate the PPE (masks, hoods) and extreme masking required for spray.  However containers are very irregular and don't need much masking, so it might be worth setting up for spray.

For me, if this were a quickie, I'd have a conversation with a Sherwin Williams Industrial dealer about their best 1-part alkyd (oil) urethane.  If I were serious, it'd be LPU all the way.  My question is, "Do I ever want to paint this thing again?"

I mention LPU, this is a 2-part (A and B part, like an epoxy) which combines a urethane A-part with an isocyanate B-part. (If this sounds scary: exactly.) The isocyanate and urethane splice to each other forming a poly-urethane molecule that is extremely long - far longer than can be obtained from a 1-part polyurethane paint, where the molecules are short.  This creates an extremely tough finish.  Any 2-part paint such as an automotive paint will be something like this, it's also used for aviation and marine.

LPU and other 2-parts are safe as houses once it cures, and the isocyanate (or BPA) in the B-part will stay in the resin and not evaporate by itself, so it's safe to brush (don't get it on your skin).  Spraying it is a whole 'nother kettle of fish.  You're turning it into a fine mist, and you must not breathe that! At all! The factory recommends an external air supply.  I prefer marine paint since it is less encumbered by environmental regs, cheaper and made to brush. It's perfectly appropriate; it's a marine container after all.

This safety issue is why 2-part paints aren't marketed to consumers, except for garage floor paint which is always rollered.


Do cracks in a brick wall signify a serious problem? Just the general Home question related the foundation. I am hoping to see your opinions and comments.
Location : North Texas
House year : 2018
Background : Bidding for this house. Only three years old, and already shows the crack on the bricks only on one side. Seeing the patio area puling away from the house.
Question: Will it be okay 5 - 10 years down the road?

The bricks separating from the threshold is a cosmetic problem, but it is a symptom, along with your cracked mortar and bricks of something more significant -- the foundation is/has settled. You should ask if the foundation (this typically occurs with slab vs. pier and beam) has been repaired. If done recently, then you have some "minor" fixes for the cosmetics.  If the foundation was repaired some time ago, or hasn't been fixed, then you should get a professional to inspect it, assuming you can get access to inside of property.
I've had this issue with two properties in the DFW area, and both times the foundation repair was approx. $8000 to $9000, which was on the low end of estimates.  That work will only fix the foundation, and it will only last as long as the owner keeps the soil watered around the house afterwards, for as long as the owner has the property. it is a result of the shifting clay soil found in the DFW area.
I had a bid to fix my cracked mortar and bricks, and the estimate wasn't too bad, but it wasn't really too large of an area (maybe $500 IIRC?). It included being able to match the color of the mortar, which (for me) was critical. I fixed the bricks at the threshold myself for practically nothing.
If the house has had foundation repairs, but the owner didn't keep the foundation watered, as we say, then there's no reason why the property couldn't need additional foundation repair.
Built in 2018? That's a relatively new home and it suggests how bad the soil is in this area, as well as suggesting how little care was given to the landscaping/area immediately around the house, since it's already messed up within less than 3 yrs.  should you pass? Depends upon your budget. The vast majority of residential properties have/had this issue in this part of Texas.
Will it last 5 to 10 yrs.? maybe, assuming the foundation is/will get repaired and how extensive the cracks in the mortar are.  I have seen similar brick walls still standing after that amount of time.  Obviously, if you buy it, you will want to fix it- either now or when you go to sell it in the future. the cosmetics won't necessarily keep someone from getting financing for the purchase, but needed foundation repairs can prevent financing.


How can I improve ventilation in my room with a window fan while filtering pollen from a nearby tree? This is a campus building in Aalto University where you have a tree about 10 cm away from the window. The Espoo city does not allow the student organisation AYY to cut down the tree. There is a poor air-conditioning in the room so the fan is essential to speed up the airflow. Without the fan, the window becomes smoky and the room very hot.

I need to find filter to the window so I can keep the fan on also during times of heavy pollen times (15x100cm for the above window). The filter must be sturdy because birds get into the room.

I tested a novel idea of using computer fans with polycarbonate plastic thing for a smaller window but the computer fans provide very small airflow in comparison to the large fan.

Which kind of filters should I use in windows like above? Is it enough to have a cloth pinned to the sides of the window? Or do I need carbon filter? Can I use filters meant for computer fans like the above?

You'd be better off with a box fan as it has a large, square area that will support your filter media properly. It will need to be powerful enough to develop airflow despite the next addition.

Not sure if you can find it, but we have here available electrostatic filter media by the roll. Cut several pieces large enough to cover the inlet side of the box fan. Mount one to the grill, keep an eye on it for pollen buildup, swap in a spare and wash the clogged one.

It's not as efficient as a HEPA filter system, but then the cost of the filter material isn't going to put you in the poor house like the cost of expensive HEPA microfilters that will quickly clog even though you keep the outer prefilter cleaned will.


blue water from coper pipes we have blue water and think something is corroding the copper pipes. Have recirculators. Problem started after flushing with chlorine and now flushed with sodium bicarb. Ideas?

a little knowledge is a dangerous thing.

you have created copper chloride dihydrate in your drinking water.  its deadly in high concentrations and is not permitted in drinking water at levels above 5 ppm.  you should flush your pipes out with vinegar or another weak acid (just use vinegar, its safe and doesn't run the risk of creating new problems.  it will dissolve the copper salt and remove it from your water. then flush the system out with sodium bicarbonate to neutralize any residual acid salts that may have formed.

and for the love of god, have your water tested before anyone suffers liver or kidney failure from copper salt poisoning.


Kitchen Faucet shuts off both Hot and cold water whenever I try to use both Kitchen faucet was replaced...now it wont allow both Hot and Cold mix to flow together always shuts off.

Look at and read the instruction sheet that is usually in the box with the new faucet. If it is a cartridge type , the cartridge may be installed in reverse or backwards.


How can I attach normal framed walls in between concrete columns? I'd like to add partitions to this grid of columns. I want to make "normal" walls, framed with 2x4 and faced with plywood or drywall. My concern is how to attach the walls to the columns. Naively, I would build the wall frames, put them in place between two columns, then put concrete anchors through the sides of the frame into the column. That strikes me as possibly not the best solution.

Your solution is fine.  I have seen that done a lot.  Although, steel studs are used more often in this type of setting.  I think I would use a Hilti gun instead of concrete anchors, this will save time, money and be more secure just  because you can have more nails than you could ever put anchors.


Name of Part That Connects Blinds Wand With Blinds Roller and How to Replace It? I have blinds where the part connecting the blinds roller and the blinds wand is broken.  The part looks like:

What's the name of this part?  How do I go about fixing / replacing it?

Looks like a "wand tilt control".

http://www.fixmyblinds.com/vertical-blind-tilt-controls-s/91.htm


How would I go about identifying and matching this wood stain color? I inherited some wooden furniture (which I believe to be oak) a few years back and was looking to add a couple of pieces to it. I want to try and get close to the same color, but I have no idea what color this actually is, so I was looking for some help. Sorry that some of the photos are a little more "blue" for some reason.

Photos are of the end-table and coffee-table.

Well first off: that's not oak. It's larch or southern yellow pine (maybe even hemlock) from the look of it. As for color, that looks very near to the natural color of softwood after some yellowing from age but its hard to say. It appears to be production grade furniture (although of a fairly high quality) which means the colorant(stain), if any, is a proprietary blend mixed specially for the manufacturer by a finish supplier (i.e. Sherwin Williams) so trying to track it down will be difficult or impossible. But don't desperate, most furniture makers have a "natural" color blend and most of them are very similar.


How can I add a switch into an existing circuit but only control some of the circuit? I'd like to put all the lights in my unfinished basement on one switch. I've got carpentry experience but only novice level wiring experience. Right now the lights are all on pull-chains. The electrical run that these lights are on also feeds lights in parts of my finished basement (stairwell and a finished guest room). I drew a diagram of the current wiring scheme below. Note, the partitions I drew under the wiring scheme are how I eventually plan to partition things (also adding a new finished room in the future). What I'm asking about right now is the area partitioned as "current unfinished space". I'd like to add a switch that controls all those lights (3 of them) but the switch shouldn't control any of the "soon to be new room", stairwell lights, or current finished guest room. Do I just need to put a junction box before the first light (and after the last) in the chain and run a wire by-passing the 3 lights from the stairwell to the guest room? Then from that same junction box, power the 3 lights/outlet in the current unfinished space? That seems to make sense to me, but wanted to make sure I wasn't making it more complicated than it needed to be (i.e. simpler solution?).

Also, assuming that's what I have to do, I'll need to re-wire that electrical outlet so it's not turned off/on by the new switch as it's currently wired, right?

This is all unfinished space so obviously I have access to the walls/ceiling. Any help/advice would be appreciated!

As you have drawn it, these lights will be always-on.  Most people do not want that, though it is becoming more popular due to LED lights drawing so amazingly little power.

Imagine with your mind's eye, if the colors of wires were related to their function.  Start with

black for the "hot" wire, that is always hot regardless of any switch positions.
White for the "neutral" wire, which is the normal current return.

Current flows in loops, so the two wires above are bare minimum.  Now let's think about a third:

Red for "switched-hot", a wire that is hot when the controlling light switch is on.

Normally we are stuck with the colors that are in cable, and don't get to color-code like this.  But in this particualr case, I think it will work out.  If not, they make colored electrical tape.

Now, light switches need all 3 wires.  If you heard that light switches only need black and red, and you can do that with black/white cable, that knowledge is obsolete.  Switches need all 3.

Lights need 2 wires: switched-hot and neutral (red white). They don't need always-hot (black) unless you want the option to jumper them on 24x7, but it's ok for always-hot to pass through their box untapped.

So the deal is, you need to run /3 cable (red black white) between all the controlled lamps and the switch.  The switch taps black and red, leaves white capped off for future smart switch use.   The lamps tap red and white, and black passes through.


New roof, ridge vent and whole house fan ?? Help! I am in the process (day1 of 2) of getting a new roof.  I have a whole house fan - Louvered ceiling type.  House was built in 1968 so I have no spec on that fan.  It has (or had after they ripped it out) a roof ventilator with fan.  The roofers removed the “mushroom” bowl shaped thing on roof and disconnected the fan from electricity.
They are telling me I don’t need it anymore because they are putting on a ridge vent.  Currently I had this ventilator and 5 turtle type vents.
Are they correct not to put the mushroom ventilator back and hook it back up?
Please help.

Powered attic exhaust fans sound like it would be an sure way to keep your attic from becoming an oven in the summer. But unless your attic is completely draft free and sealed from the living space below running an attic fan will increase your electric bill and increase the cooling load on your HVAC (cooling).
When the attic fan runs it is pulling air from the house while make-up air is being drawn in from the outside through any gaps (door thresholds, window frames, etc.) your conditioned cooled air is being pulled into the attic and exhausted out the vent.
A ridge vent when properly sized, allows an easy route for the hot attic air to escape;the vent is at the highest point in the attic.
The make-up air being drawn in is through the soffit vents (openings).
If the roofers have calculated how many roof vents you need accurately than there is no need for the energy consuming powered fan. A quick way of finding the number of attic vents is for every 300 square feet of attic floor space there should be 1 square foot of vent opening*.
*Audel HVAC Fundamentals, Volume 1.


What's the right way to mix and use boric acid spray for fleas? My fleas were begging for it, so I let them have it.. sort of
After an hour of trying to figure out why my sprayer won't spray properly I have realized boric acid is not soluble in water. Or is it ?
As i have read over the interwebs, boric acid = borax + salt in a 5:4 mix ratio. There were crystals in the water + boric acid mix (about 200g per 4L) which would clog my sprayers. Would I be guessing correctly those insoluble crystals were the salt ?
I took out the crystals, put the solution in my sprayer and sprayed all over the place. Upon drying a noticeable film of something got laid out where I have done the spraying. Is that the borax ?
And for future referents, should we buy just borax instead of boric acid if we wanted to dissolve  it in water ? What ratio borax : water if so ?

Here is a partial answer: heating the water helped a lot. I have boiled 1.5L, mixed with 0.5L tap water (summer time) and dissolved 100g boric acid in it completely.


What is the max span that can be supported by 2x4 floor joists? We had old 2x4 floor joists sitting in our bathroom that we ripped out as they were rotten and falling apart.
2x4 is ideally our limit of thickness, and I was thinking of having 4 or 5 2x4 joists going from one end of the wall to another (147cm / 58") bolted to a 2x4or 2x6 (not sure which one) bearer against all 4 walls. The bearers will be thunderbolted to the brick walls and joist hangers will be used for the 2 by 4s.
I have a very poorly drawn picture from myself to illustrate the 2 by 4 joists. We're thinking about putting the joists 30cm (12") OC.
How much weight can this take? Is this adequate for a room that is 7 ft 9 inches?
Based in the UK.

See a video of the floor.
https://streamable.com/2wbrxk

I’m American so I don’t understand the metric system, but I’ll try to answer.
When you ask for the maximum span of a 2x4 floor joist at 12” on center, there are many issues. We design from the top down and build from the bottom up.

Your subfloor must be rated to span from joist to joist. If you use 12” spacing then a 1/2” thick board is acceptable, but at 16” spacing you should use 5/8” plywood and for 24” spacing then use 3/4” thick plywood.  This is based on supporting 15 lbs. per square foot of Dead Load and 65 lbs. per square foot of Live Load. (This is higher than normal, but will allow you to use a tile floor without deflecting too much.)

The maximum span for joists depends on species and grade. I’ll assume an average grade of Number 1 (C16). C16 is economical to use and easy to find. So, for 2x4 at 12” oc the maximum span is about 7’-6”, which is about the distance you need. (If you go to C24 it could be longer.) Remember, spans are measured from face of support to face of support.

Joist hangers are also rated. Finding a hanger that will accept a true 2” wide joist will be difficult. Simpson has a hanger and is rated for 600 lbs., which is fine for your application.

Using a perimeter ledger could require a 2x6, because you need 4 times the bolt diameter. A 1/2” bolt would require an edge distance of 2”. A 1/2” bolt will need to be about 12” on center to support your load.