Electrical design for a house with an ADU, solar, and backup generator I recently moved into a fixer-upper house, and have some questions about how to go about (re)designing the electrical system in a way that meets my somewhat unique timeline and site requirements.

This is my current situation:

200A service with Puget Sound Energy.
Existing panel is a smaller split-bus panel.
Electric service serves only the main house and some exterior lights/outlets.
The house is 3,000sf with electric heat, stove, water heating, etc. (i.e. the house is an all-electric house).

My remodelling project is spread out over multiple projects, which mainly consist of the following sub-projects, which will likely be completed in the order listed.

Drilling a new private water well, replacing a shallow century-old shared well on an adjacent property.
Construction of an outbuilding which contains a shop and an ADU for guests and, perhaps in the future, renting out.

The shop will have woodworking tools in it.

Re-wiring of the main house concurrent with a whole-house remodel.  Construction of an addition will bring the total square footage to 3500sf.

The home's HVAC will be replaced with mini-splits.
A heat pump water heater will be installed.
Currently the house has nearly zero insulation.  This will also be rectified.

The addition of a backup generator serving hopefully both the house, the ADU, and some common loads such as a well pump.
Electrical service will be upgraded to 320 or 400A.
Lastly, I'm considering adding some solar panels.

These projects will likely be done piecemeal over multiple years, but I'd like to first design the electrical with the final product in mind, and minimize any work that I'll have to re-do later when, for example, my service is upgraded to 400A.

Summary of current equipment

Current meter base.

Current load center. The panel is exactly opposite the meter socket right now on the inside of the house.

The Exterior Subpanel breaker is connected to this indoor-panel-mounted-outdoors-without-a-cover subpanel outside.

The first two 30A double pole breakers are hooked up to the water heater and the oven. The rest are unknown.  I assume one goes to a sump pump; not sure where the other ones lead. I have some random outlets mounted to trees on my property from conduit that comes out of the ground; perhaps it's one of those.
Central Heat Pump.  Sorry for the spiderwebs:

While this is a pretty complex all-electric situation, I'm hoping to squeeze everything into my 200A service for the time being, until later on when it's feasible for me to upgrade to 400A service. I think the first step would be to upgrade my main house's panel and meter base so accommodate the first project (construction of the ADU/shop).  Since my existing panel is pretty much full, it would be nice to get a fresh modern panel into the home, from which I could branch off to the shop/ADU once it's built, and then gradually move all my circuits into that panel.

With that in mind, I'd like some suggestions/help for the following:

What is the best way to design the shop/ADU feeders/panels to best work with what I have now, but with upgradability in mind?
Can I have the generator power both the house and the ADU if they end up being on independent feeders?
How would grid-tied solar fit into everything, once I get around to installing it?

Accessory dwelling units are complicated

While outbuilding feeders and standby generators are both common things to have -- your combination of having an accessory dwelling unit in the outbuilding with standby generator support for that accessory dwelling unit, alongside having shared, or "house", loads, such as the well pump, that will also need standby power, makes this a significantly more complex problem.

Why? Because accessory dwelling units throw a kink into the way NEC 210.25 is interpreted:

  210.25 Branch Circuits in Buildings with More Than One
  Occupancy.

  (A) Dwelling Unit Branch Circuits. Branch circuits in each
  dwelling unit shall supply only loads within that dwelling unit
  or loads associated only with that dwelling unit.

  (B) Common Area Branch Circuits. Branch circuits installed
  for the purpose of lighting, central alarm, signal, communications, or other purposes for public or common areas of a two-family dwelling, a multifamily dwelling, or a multi-occupancy
  building shall not be supplied from equipment that supplies an
  individual dwelling unit or tenant space.

This code section, more commonly seen in the context of full-fledged multi-family buildings, basically requires one of two power configurations for any property that has more than a single dwelling unit in it:

Master metered, where all dwelling units and the shared/common loads are fed off of a single meter
Individually metered, where each dwelling unit gets its own meter and the shared/common loads are metered separately from all dwelling units/tenant spaces.

Furthermore, the master-metered approach is discouraged (albeit not prohibited!) by PSE in their General Rules and Provisions:

  The Company may refuse to connect service to a master meter in any new building with
  permanent occupants when: there is more than one dwelling unit in the building or property;
  the occupant of each unit has control over a significant portion of electric energy consumed
  in each unit; and the long-run benefits of a separate meter for each customer exceed the
  cost of providing separate meters.

Given all this, and that the general Code requirements for accessory dwelling units are a complex and evolving affair, with local code amendments often written by folks who mean well, but do not always understand the NEC impacts that result from their writings, we need to design our electrical system with the individually metered approach in mind, even if we can get by with a master metered approach for now.

As a result of this, we need to rigorously separate the equipment for the three systems (main, accessory, and shared/"house") everywhere beyond the meter-main.  This means we need 3 main-unit subpanels, 3 transfer switches, and 3 standby subpanels, in addition to the existing main panel in the house, which can be reused as a subpanel, or replaced as needed.  We also need to make sure that we don't paint ourselves into a corner that prevents the setup from being upgraded to 400A.

How can we size this?

Service and feeder sizing is determined by a set of relatively complex rules located in the NEC's somewhat-infamous Article 220.  These rules cover just about every sort of building under the sun, but have several special cases that apply to dwelling units (aka houses and apartments), as well as a simplified set of rules for that dwelling-unit case (220.82), which we will not be using here as they are difficult to apply to multiple-unit situations like yours.

The current situation

Our starting point, of course, is the house you have now, with:

3500 ft2 of floor area (times 3VA/ft2 for a total of 10.5kVA of general load allowance)
3 kitchen branch circuits & a laundry branch circuit (6kVA at 1.5kVA apiece)
A standard, tank-type electric hot water heater (4.5kVA)
An electric clothes dryer (assumed at 5kVA)
A separate cooktop and oven, with the cooktop at it's 7kW nameplate rating and the oven consuming as much power as a 30A branch circuit will let it (aka 7.2kVA)
The existing 3/4HP, 115V drainage pump (1587VA using the 13.8A@115V figure from Table 430.248)
And the existing HVAC system, consisting of a 5 ton heat pump with a 32.3A outdoor unit and a 57A air handler/auxiliary heater. (We are assuming the basement heater is shut off for the purposes of this load calculation to simplify things.)

Applying the Part III (standard) method from Article 220, we start by applying the 35% demand factor for receptacle loads (general lighting and small appliances) over the baseline 3kVA, giving us 7.725kVA of factored general load.  Atop that, we add the water heater, dryer, and cooking appliances, giving us 31.425kVA of non-motor/HVAC load overall as no demand factors apply here.  Finally, we apply the motor and HVAC loads, with the outdoor unit at its branch-circuit selection current as the largest motor as per 440.7 and the Exception thereto, giving us 9286VA for our largest motor (the outdoor unit), another 1587VA for the drainage pump, and 13.68kVA for the indoor unit, for a total load of 55.978kVA, or 233A at 240VAC.  (The alternate calculation in 220.82 yields around 150A, so you probably are not overloading your service at the moment, but this is tight.)

As we shuffle things around...

Of course, this will change as we add loads.  We start with the new factored load from the ADU and shop space, consisting of the general lighting load from both spaces at 864 ft2 each * 3VA/ft2 = 2592VA per space as well as the 4500VA small appliance load from the ADU.  This sums up to 9684VA, which all gets demand-factored at 35% for service calculation purposes to yield 3389VA of additional factored load on the service.  However, the ADU feeder needs a separate factored-load calculation, yielding 4432VA of factored load for ADU feeder sizing purposes, and 2592VA of factorable load, with no demand factors applied, for shop feeder sizing purposes.

From there, we then add the HVAC loads for each space.  The representative units I have chosen to provide an appropriately conservative load calculation are 18kBTU (1.5ton), 20 SEER, Mitsubishi inverter units that consume 12A at 230VAC, or 2760VA, apiece -- the real units used will likely be smaller still as modern building methods can produce vastly better envelope load performance than 500sf/ton.  This is the largest motor load in the ADU, as well, which means that we must apply a 1.25 factor to it for ADU feeder sizing purposes, resulting in an additional 3450VA of ADU feeder load, an additional 2760VA of shop feeder load, and an additional 5520VA of service load.

We then add the loads specific to each unit.  For the ADU, we have 4500VA for a separate, tank-type, electric hot water heater, 5000VA for its own dryer, and 8000VA as a range allowance, permitting up to 12kW of range as per Table 220.55: this all adds up to an additional 13.5kVA of ADU feeder load and service load.  For the shop, we add a 28A@230V (5HP) dust collector, our largest motor here, which adds 8050VA of load by itself, as well as a 13A@230V tablesaw which adds another 2990VA of load, and a 1500VA allowance for an additional tool that is in use at the same time, yielding an additional 12.54kVA of shop feeder load, and 10.93kVA of service load (as the dust collector is not the largest motor on the service).

At this point, we can compute the loads on the ADU and shop feeders.  The ADU feeder has 3389VA of factored load, 3450VA of HVAC load, and 13.5kVA of fixed appliance load, adding up to 20339VA of feeder load, or 85A@240V.  This is within what a 100A feeder can handle, and also means that there is very little chance that we will need anything larger than 125A for the ADU.  The shop, then, has 2592VA of factorable load, 2760VA of HVAC load, and 12.54kVA of machinery load, yielding 17892VA of feeder load, or 75A@240V.  Again, this means that a 100A feeder will be sufficient for the shop, with a 125A feeder available as a future upgrade option.

We then move onto the shared-loads feeder.  We start with the factorable load, which consist of 320VA for the 16x20 storage shed, 200VA for the 200W streetlight, and 360VA to account for exterior receptacles (180VA for one on the shop/ADU building, and another 180VA for a premises receptacle, if present) for a total factorable load of 880VA.  We then add on a 17A@230V (3HP) well pump motor, or 3910VA of service load and 4888VA of feeder load, for a total of 4790VA of additional service load and 5768VA, or 24A@240VAC, of feeder load.

Finally, we return to the main house.  The 13.68kVA from the auxiliary heat goes away, but we add a 24A@240VAC car charger for an additional 5.76kVA, yielding a new main house load of 48.058kVA, or exactly 200A@240VAC for that feeder.  The service load, though, is computed by adding all the factored and non-factored loads separately, yielding 80.427kVA of total service load, or the need for a 335A service at 240VAC to accommodate the full scope of this.  In other words, you will need to make sure that the service upgrade to 400A happens shortly, or else you will have issues with the main breaker in the meter-main tripping (if you have a single main breaker, that is).

Starting with the meter main...

There are multiple types of meter-main hardware out there -- meter-breakers, meter-loadcenters, and multi-meter-breaker stacks.  Due to their lack of flexibility, full-fledged meter-loadcenters (combination service entrance devices, "all in ones") are a poor choice in many applications, so we will not consider them further here, although many manufacturers do not cleanly distinguish between devices that are closer in nature to meter-mains from devices that are designed solely as all-in-one meter-loadcenters.  We will first consider the meter-breaker approach, as applied to your existing 200A service, and then discuss the 400A upgrade options available to you.  Finally, we will talk about multi-meter hardware, as it has some complications in it that are not present in single family metering.

During all this, we also have to keep some requirements imposed by your utility in mind:

As an EUSERC utility, PSE requires ring-type metering hardware
PSE considers "house panels" for common loads in multi-family dwellings to be commercial loads, requiring a manual (test block) bypass facility in the meter socket for the common loads meter
PSE forbids test block bypasses on 200A meters feeding individual dwelling units, but requires a manual block bypass on 320A residential meters
PSE requires engraved identifying plates on individual meters in a multi-meter setup -- any shop that can engrave trophies can handle this for you
PSE also requires a production meter in-line with the solar feed in some (many?) cases, colocated with the rest of the metering

The simple case -- breaking out what you have now

While I would normally suggest "rule-of-six" meter-mains for an application like this, the heavy oversubscription potential of the existing 200A service with this additional wiring is a legitimate concern, and there are a couple ways to handle this.

If you wish everything in one box, the Milbank U5169-XTL-200 is an EUSERC-compliant, 200A meter-main setup that uses a backfed 200A main onto a 12-space main lug loadcenter, leaving 8 spaces for branch breakers.  For this unit, you would be using a Siemens QN2200RH for the house main, with a pair of Q2100Hs for the common-load and ADU feeders.  However, it would mean that you would have to feed the shop through the house panel until you upgraded to 400A service.

The other alternative here, at the cost of an additional enclosure, is to use a single-breaker, ring-type, EUSERC-compliant, single-breaker 200A meter-main, with a 2" nipple with 3 4/0 Al XHHW-2 wires in it connecting it to a 12-space, 200A, main lug, outdoor (NEMA 3R) panel with matching 200A and 100A breakers, as well as accessory ground bars and lugs for any large ground wires exiting.

Either way, you will need to clean up your existing panels at this point.  In the split-bus panel (a Murray, by the way), all the bare wires need to be moved to the left-hand bar (the ground bar), all the white wires need to be moved to the right-hand bar (the neutral bar), and the bonding screw that electrically connects the right-hand bar to the case needs to be removed.  If the right-hand bar is not sitting on black plastic insulators, you will need to replace it with a Murray ECINSNB33 insulated neutral bar kit at this point, as well.

The small outdoor subpanel will need some more extensive work.  Once you banish the cobwebs and debris from the cabinet, you will need to replace the interior trim (deadfront) with a Square-D 4055802102 (as per here and here), mounting the new trim piece using a Square-D 4020513001K fastener kit.  While you are in there, you will need to fit a Square-D PK7GTA ground bar to the loadcenter, remove the bonding screw from the neutral bar, and move all the bare wires from the neutral bar to the new ground bar.

Alternatively, you could replace the subpanel with a brand-new HOM612L100RB with its bonding screw pulled and a PK7GTA ground bar fitted, reusing the existing breakers.  This does require the extra labor of pulling the wires out of the old enclosure and swapping them over to the new enclosure, though.

Going bigger

When you want to go to 400A service, your hardware selection becomes much more limited.  Fortunately, Square-D does make something suitable in the QO line: the CU12L400CB provides a 200A disconnect with space for a second 200A disconnect, as well as a 200A, 8 space QO interior providing room for up to 4, 2-pole, 125A maximum QO branch breakers.  This allows us to put the main house on the factory-fitted 200A breaker, the ADU on a QO2100VH, and the house loads on another QO2100VH, while leaving the spare 200A space available for either more power to the main house or a larger ADU feeder and permitting a separate QO2100VH for the feeder to the shop space.

Giving everyone their own meter

While the normal "go to" for this would be some sort of meter-pack type setup, since you want (and need) 200A to the house and 100A atop that for the shop, you'll need to go with a split setup.  The main house and shop feeders in this case are handled by a CUM400CB with a BMK2Q400 kit used to fit QDL2200 and QDL2100 feeder breakers for the main house and the shop, respectively.

With that, we use two individual meter-mains for the other two meters.  One of them needs to be a 100/125A, EUSERC-compliant, underground-feed meter main with a test block bypass function and a 22kAIC main breaker, such as a Milbank U214MTB/22, an Eaton CHU214MTBLB (with a BRH2100 main), or a Cooper U214MTBH, for the common-loads meter, while the other is  a 100/125A ring-style meter main, also with a 22kAIC main breaker, for the ADU's meter.

Last but not least, we need a way to connect the various service-entrance conductors from the meter-mains to the utility service lateral.  The simplest approach would be to use the meter sockets to house splices, but that doesn't work as PSE's rules forbid using meter bases as junction boxes.  Double-lugging the 400A meter-main doesn't work either as Square-D does not support that, and we can't use a regular NEMA 3R pull box to house the splices as EUSERC rules require a special two-bolt arrangement for the utility service lateral conductors to land on instead of having them land on a customer-provided lug.

This leaves us looking at the approach used in commercial work, where a termination box is used to land the service lateral from the utility, connecting it through to a bussed gutter that distributes power to the various meters.  However, given the constraints of our setup, a bussed gutter is a costly piece of overkill; it is far simpler to splice the service-entrance conductors directly in the termination box using insulated mechanical splice connectors, connecting them to jumpers to the termination box's customer-side lugs.

For this, we use a Milbank TB-014 box, some 600kcmil Al XHHW-2, some 1/0 Al XHHW-2, and three four-port, Al9Cu insulated mechanical tap connectors capable of accepting wire from 1/0 to 600kcmil, minimum.  The 600kcmil conductors from the tap connectors run onward to the 400A meter main via 2.5" EMT and a set of CMELK4 lugs at the meter-main end, while the 1/0 Al wires run via 1.5" EMT to the 100A meter-mains with prefabricated EMT elbows to turn up into the bottom knockouts on said meter-mains.

As to the feeders...

Once we have the meter-main(s) out of the way, we then run a feeder out to the new panel for the main house, using a 4/0-4/0-4/0-2/0 aluminum type SER cable. (Normally, I'd use XHHW-2 aluminum singles in conduit sized to allow for upgrades for such heavy wiring, but accommodating a 400A feeder requires a larger conduit than will fit within a 2x4 stud wall, making that approach rather impractical.)  We can also use this same type of cable to subfeed the existing 200A panel from the new main house panel location in case it is desired to keep that panel in service.

We do use the conduit approach for the other two feeders, though, as the common loads panel can live on the outside of the house, and using conduit allows for easy upgrades of the shop/ADU feeder(s) as well, saving upgrade costs tremendously over using a direct burial cable.  The common loads/solar production feeder, then, uses 3 1AWG aluminum XHHW-2 wires in a 1.5" EMT run off to a convenient spot on the outside of the house where the associated panel can live.

As to the run to the ADU/shop outbuilding, we will use 2.5" conduit here. This provides sufficient space for whatever you wish to run to there, up to 3 2/0 Al XHHW-2s for 125A to the ADU alongside 3 more 2/0 Al XHHW-2s for 125A to the shop space although 1AWG Al XHHW-2 will be adequate for both feeders for now, 3 4AWG Al XHHW-2s for a 60A generator feed to the ADU, and two 6AWG bare copper equipment grounding conductors, one for the shop space, and the other for the ADU (as this avoids splicing in the T-body).  While you have the trench open, you'll want to lay a second conduit (1.5" suffices) to serve as a communications duct between the main house and the ADU, considering that those wires can't be run in the same conduit as mains wiring.  Furthermore, this smaller conduit can also carry the control wires running to the generator set from the transfer hardware in the ADU, as these run at 12VDC.

Alongside this, we have three other conduits to run, all 1.5" in diameter.  First is the conduit carrying the control wires to the generator from the communications box at the house; next to it, we have another 1.5" conduit for the generator source lines, which consist of 3 1/0 AWG Al XHHW-2 wires and 2 10AWG THHN wires (for the generator's battery charger) alongside a 6AWG bare copper ground (really, a supply-side bonding jumper as per NEC 250.35(B), but it basically serves the same function as an EGC). The remaining conduit here can be another 1.5" conduit carrying 2 10AWG copper THHNs and a 10AWG bare copper ground for the well pump branch circuit.

Finally, we have the feeders to the storage shed and solar panels from the shared-loads panel enclosure.  These feeders can be simpler than the rest, due to the relative paucity of loads present there: 3 4AWG Al XHHW-2s and 3 10AWG Cu THHNs in 1.5" conduit with a 10AWG bare copper ground will handle both feeders, with room to spare in the conduit to go up to 2/0 Al XHHW-2 with a 6AWG bare copper ground, while keeping the existing 10AWG shed feeder wires, if you want to expand the solar panels in the future.

And the panels themselves...

The main problem with using conventional panels for this is that we would need 8 panels -- 2 each for the main house, the common loads, and the ADU, as well as a subpanel for the shop and a breakout panel for the generator feeders.  This, along with the 3 automatic transfer switches, the meter-main/meter-pack, and the existing panel(s) in the main house, would make for a simply unmanageable morass of distribution hardware.

Fortunately, Siemens makes what they call a "GenReady" panel.  This is a convertible (between main lug and main breaker) split bus panel that can be fitted with either a manual generator interlock or a power controlled transfer switch that lives within the panel, allowing us to consolidate the number of new enclosures down to 7 from 15 if we are reusing the existing main house panel as a subpanel.

While the transfer switch hardware that normally goes with this is designed to work with certain Generac generator controllers that also provide transfer "brains" themselves, it is possible to get a third party module, the PSP Products KGC-1, that provides the transfer control and generator start logic itself, allowing the use of any 2-wire start generator. (The documentation for the module only mentions Kohler generators, but the "4" output from the KGC-1 is really a standard 2-wire, 12VDC run signal.)

Starting right at home

As a result, we can accomplish this starting with a 12-space, NEMA 3R panel with a 100A main breaker, such as a Siemens PW1224B1100CU with an ECSBPK04 interlock kit fitted, that is used as a generator distribution board to provide individual standby feeders for each part of the system, along with 3 of the Siemens generator panels, and a 30-space, 125A, main breaker panel for the shop space.

The reason we are choosing a main breaker panel with a separate main breaker space for the generator panel, by the way, is it allows us to fit it with an interlock kit, 50A breaker, and CS6375-type inlet to allow a portable standby generator (with its neutral-to-ground bond pulled) to be plugged in and used in case the hardwired one breaks down during a power outage.  You will need a set of ground bars for this panel if it is not factory shipped with them, and you also will need an ECLK2SC lug for the neutral to the main house.

From there, we move onto the main house, which receives a Siemens G4254L1225GEN generator panel as it's new primary subpanel, fitted with its matching GENTFRSWTCH ATS, a PSP KGC-1 ATS controller, and an ECLK2SC neutral lug if needed for the generator feeder neutral.  The existing was-a-main-panel then gets subfed from this panel using an ECLK2225 subfeed lug kit with an ECLK3 neutral lug and an ECCS2 grounding lug to fit more of that 4/0-4/0-4/0-2/0 aluminum SER cable for the subfeed run.

Now, we can tackle the common loads panel. This panel is a Siemens W3042L1225GEN, again fitted with a GENTFRSWTCH and a KGC-1.  This will feed the streetlight, well pump, and any other loads that are common to the property as a whole, such as receptacles and lights that are not attached to either building or on the outside of the ADU/shop building, since the latter is fed from two different sources.  It also is where the feeder for the storage-shed originates, as well as having a 125A meter base for the production meter attached to it with a 1.5" nipple.  Last but not least, here, the 14/4 TC from the transfer switch to the comms/control pull box can be pulled through a 1/2" EMT to protect it.

Heading for the outbuilding...

From there, we move onto the outbuilding.  The 2.5" power and 1.5" communications conduits go up the outside of the building, with an Arlington 936NM in a TB configuration for the branch off to the shop panel and a pair of LBs routing the rest of the conduits into the ADU on the second floor.  The communications duct, by the way, will simply exit into the wall at each end, terminating in bushings to protect the wire edges.

We then fit a G4254B1200GEN for the ADU's panel; once again, this panel sports a GENTFRSWTCH transfer switch and a KGC-1 transfer controller.  From this transfer controller to the main house, we run a 14/4, wet location rated tray cable in the communications duct; these cables are more commonly seen in industrial work, but work just fine closer to home as well.

Finally, we fit a P3030B1125CU for the shop panel.  This panel requires no special treatment, unlike most of the other panels here.  However, the shop cannot share any "utility" loads with the ADU; this not only means it will have its own mini-split, but that it will need its own hot water heater as well, considering that the shop will have a washroom space associated with it.  Fortunately, this is a good application for a small tankless hot water heater in the 3-6kW range.

Dealing with that other shed

Now that we have the rest of this in place, we can fit the panel for the other shed now.  This will be a BR1224NC125R, with a BR260 fitted for the main using the supplied hold-down screw and a BR220WH fed using the shed load feeder for the light and outlet circuits.  This does require using a wirenut in the panel for the shed load neutrals instead of landing them on the neutral bar and using a receptacle or deadfront type GFCI for the shed outlets, but allows us to get everything here into a single box.

If you want to use standard ATSes instead...

If you wish to use standard automatic transfer switches instead of the decidedly non-standard/adapted hardware mentioned above, you can still do this with the Siemens GenReady panels -- each panel, instead of getting a GENTFRSWTCH with its associated Q215 voltage sense breaker and Q2100 generator breaker alongside the KGC-1 controller, will have the factory fitted molded-case switch for the utility power replaced with an ECLK125 subfeed lug kit, reusing the existing hold-down parts.  The factory jumpers are removed, and then the bottom half of the panel becomes your standby subpanel, with the factory utility breaker in the panel feeding the transfer switch utility input and the transfer switch output feeding the bottom half of the panel via subfeed lugs.

Another approach to this that gets you by with the same number of additional enclosures is to use standard 200A or 225A panels for the unit main panels alongside ATSes that have built-in standby subpanels.  This does limit your ATS selection more than the former approach, though, but does provide more panel spaces for non-standby loads.

Of course, both of these approaches mean you have 3 extra enclosures in your system compared to using the full capabilities of the Siemens GenReady panels, but if you need transfer switching functionality that the GENTFRSWTCH/KGC-1 combination cannot provide, these alternatives can get you there.

Other notes

First off, the communications duct to the ADU and the control-wires conduit to the generator should terminate in a NEMA 3R pull box on the outside of the house.  This provides a place to connect the control cables from the transfer switches to the control cable to the generator, as the KGC-1 control contacts can be connected in parallel; it also can house things like the house-side primary protector for any telecoms lines for the ADU.

Next up, the outbuilding will need a grounding electrode system of its own.  If you're building it from scratch, a concrete-encased electrode in the foundation is highly recommended (and required by some local codes).  In case that's not an option, though, there is always the old standby of using two 8' ground rods, driven 8' apart.  You'll need to use a 6AWG copper GEC, by the way, run to both panels in the outbuilding (shop-panel and ADU-panel).  This will also need to be bonded to the water service line coming into the ADU with a 6AWG bonding jumper and split bolt if a metal pipe was used for it, as well as to the communications raceway if it is made of metal, and to the primary protectors on the communications cables run to the ADU, using an intersystem bonding termination block as per NEC 250.94 and some bare 10AWG copper for the communications bonding jumpers.

While we are grounding outbuildings, the shed will also need two 8' ground rods driven 8' apart and connected to each other and to the shed's panel with a 6AWG bare copper GEC.  A split bolt and another 6AWG bare copper wire can be used to tap it at a later time if a second panel is added at the shed.

As to the grounding electrode system at the main building, you will want to take the existing GEC, remove it from the panel, then pull it out and re-route it to the largest meter-main.  In the multi-meter-main configurations, you will also need to tap the GEC with split-bolts rated for 4AWG wire and lengths of 6AWG bare copper wire for the tap conductors to the other two meter-mains.  Finally, you will also need to fit an intersystem bonding termination block to the new GEC and run any communications ground wires present to it, again as per NEC 250.94.

Finally, and importantly, you will need to use an inch-pound torque wrench or torque screwdriver to torque all electrical connection screws and bolts to the manufacturer's specified torque.  This requirement was introduced with 110.14(D) in the 2017 NEC, but is a good idea even if your jurisdiction has not adopted it, lest your electrical system do what Greg Biffle's infamous lugnuts did.


Anyone have an idea about unidentified constant noise/vibration in single-family house? I cannot find the source of a constant noise & vibration that have recently (month or so) been happening in our single-family house. I've asked 2 different people, including our handyman, who checked several things, but so far only I have been able to hear/feel it.

We are hundreds of feet away from any neighbors. I've lived in several apartments and if this weren't a single-family not right next to anyone I'd be sure the noise I was hearing was either 1) a neighbor in an apartment below (only a crawlspace there) playing either an upright bass, constantly day in, day out, or music with a deep bass line.. or 2) Someone's tv on very loud at a distance, or 3) An engine of a machine of some sort with a low, constant, repetitive bass sound. Rapid Boom boom boom boom, Boom boom boom boom, over and over; I can feel the vibration in my feet or in my hand if I put it on the wall.

The house has electric baseboard heat, there is no furnace. There is a new sump pump that was installed around the time of the noise starting, cut the circuit to it off, no difference in the sound. Unplugged the fridge, no difference in the sound. I walked around the entire neighborhood trying to hear if it was coming from someone's house; nothing. The only thing we haven't tried is cutting off all electricity to the house. I guess that will be next.

It's beginning to really wear on me just as though a neighbor were playing loud music non-stop on and on and on, and I'm afraid it will begin to affect my health if it keeps up. Does anyone here have any ideas, suggestions?  I hope??!!

Throwing the main breaker on your electric panel is easy; you should try that. If cutting the power to the whole house stops the problem, then turn the power back on and start turning off circuits one-by-one. Hopefully they're labeled so you can identify the appliance or room, but this may take some trial-and-error.

Here are some other possibilities I can think of:

Pump for well water (if you have it).
Some other vibration coming in via municipal water line (although I can't imagine what would cause repetitive vibrations from a water main). If you do get water from your city/town, try to find the main service entrance and put your hand on it, to see if the pipe is vibrating.
An exhaust fan: maybe in your attic?
Radon mitigation fan (these typically run 24/7, drawing air out of your basement/crawlspace, through a duct).


Way to lower the mattress inside a cot gracefully I'm having a hard time transferring my son to his cot without waking him - the moment I lower him into the cot, he wakes up.

If I can raise the mattress inside the cot, and then lower it slowly once he is on the mattress, I figured it would be a lot easier.

Do you have any ideas on how to accomplish this in an easy enough way?

Been there, and I sympathize (survived 3...)

Does your cot have a side that lowers? That helps.

It does get better with practice...

One thing that may help is to cuddle them with a blanket and lay them down with the blanket - often the colder bedding is the trigger to wake them...

The other thing we did was to use a sheepskin for them to lay on - very good for temperature - apologies to any if that is a "left-field" solution...

Aslo we never had "silent mode" in the house, even if the kids were having a lunchtime nap, it was hoover as normal etc - they soon slept through it...


How safe is having my boiler in my daughter's bedroom? I just moved into a new house where the 10 year old boiler is located in the bedroom where my 3 year old daughter sleeps.

I'd like to get an idea of how safe/dangerous this situation is. Could the boiler explode? Could it create a fire in the house? What about a gas leak?

Gas leak
A gas leak could be deadly not only due to inhalation, but also as an explosion hazard.
Carbon Monoxide
Carbon monoxide is an silent killer. It's colorless, odorless, tasteless, and can kill you before you know you're dead.
Combustion Air
If the home is sealed tightly, and a source of makeup air is not present (for example if the source is supposed to be the open door, but the door is closed) there could be a suffocation hazard. As the boiler burns fuel, it also uses up air (oxygen). If a sufficient source of new air is not available, the life supporting oxygen in the room could be used up.
Fire
Any time there is fire (or any heat source) in a home, there is always the potential for an uncontrolled fire.  A fire starting so close to a sleeping child (or anybody for that matter), could likely be fatal.

I would not put my daughter in a room with a fuel burning appliance, or any appliance for that matter. Utility appliances belong in a utility room, not a bedroom.
NOTE: I wouldn't put my son in the room either, if I had one.  I may put an in-law, or a house guest that's been around too long in there though.


Can you waterproof Luxury Vinyl Tile floors without grout? My questions are on the use of Luxury Vinyl Tile (LVT) flooring - my preference is to use the LVT without grout. However, I'm skeptical on how well the LVT will hold up to moisture without the grout and cleaning will be an issue.  Am I right about the need for waterproofing or would the flooring work well any way?  Is there a way to waterproof the joints on LVT without grouting? If water gets between the floor tiles as you step out of the shower will it cause even bigger problems?

In some areas, you can get away without having grout, but the tiles will be more susceptible to damage because grout (or something) adds strength to the floor (and keeps the tiles in place). You may have seen or heard about how some people make really tight fittings with beveled tile, and they don't use grout. This is more for areas that are onramental or where contact with water is unlikely.

In the bathroom, I think it's safe to say that you need something between the tiles especially because there will be water (on the floor). Another purpose for grout is to protect the underlayment from water... water damage could be summarized as swelling which can cause lifting/ungluing of tiles and warping and loosening of the wood and rotten/weakened wood or just plain mold and mildew. And yes, cleaning will be an issue without grout or something between the tiles.

There are alternatives to cement grout; you should search online for grout alternatives. Epoxy and caulk come to mind. If you don't put something in there, something else (dirt) will eventually fill in the gaps.

Edit- (based on the comment "my ex-husband already laid the tiles without spacing for grout")I don't like to promote products, but I'm not aware of any other silane vinyl sealers, so try a product called Infuze. Here's the technical data sheet. Like I said, it's a silane product that I think will work for this. It's kind of messy and smelly and dries quickly (so work as quickly); it will definitely seal vinyl seams. I think it chemically bonds to vinyl to create vinyl silane. It dries clear and doesn't discolor.


What's the nail size for attaching 2x3 furring to joists? I am installing 2x3 furring strips(16 oc) to joists in basement for hanging 5/8 drywall. Should I be using 10d or 12d or 16d nails?  I guess 16d may be overkill. The joist are 4x10s with 48 inch oc. I can add 2 nails for each joist.

The nails you want to use would be the coated style of 16d. These are the ones long enough to go through the 1.5 inch thickness of the 2x3s and still get good purchase into the overhead beams. The coated nails (slight greenish or brownish in color) are designed to really bind in well into the wood so that they do not pull out easily.

Do not use the common uncoated type nails.


How to fit a pvc window to a corrugated metal shed I have a corrugated metal shed which i want to fit a pvc window. I am not so sure how should i approach to this. The shed looks like the one pictured below but there are 2 vertical perimeter channels on the gable end ( Same as the side walls in the picture)

I know these bars wont carry the load of the window alone so i need to build some sort of a supporting timber frame but i need some advice on this since the gable end of the shed usually takes some strong winds and a lot of rain.

Also, whats the best way to water proof groove shape of the metal sheeting? expanding foam?

groove depth is 32 mm on the sheets and the supporting horizontal perimeter channel behind is 35 mm
Upvc window is 70mm thick with 60mm slot at the bottom

Here is crappy thing i drew on ms paint which might be useful :)
grooves are actually running vertical, so not like the drawing

Actually they probably will carry the load just fine. The general process is this

Buy the window size you want in vinyl. It should fit between the framing members (you do not want to cut those)
Buy some aluminum channel bars ("C" shaped). You'll need 4 at least as long/wide as your window. Construct a frame from these pieces, using two channels on the sides to support the top and bottom. You'll have to cut the top and bottom to slide over the shed wall itself. The finished frame should wrap the opening, leaving just enough room for your window. If the channel isn't painted, now is a good time to paint it. Caulk the top and sides with the best outdoor caulk you can get.
Insert the window with some exterior caulk to glue it in. Screw through the window flanges into the frame from the inside (short self-tapping screws should work)
Get some wood or metal (wood is probably cheaper) and run it vertically between the horizontal supports of the shed frame. You'll want to L-bracket it to the frame or floor and screw through the outer shell to this vertical support. This will help support the weight of the window and keep the sheet metal wall from pulling away from the frame
Make a flashing (spare sheet metal will do) to go over the top of the window frame. It should extend at least half an inch beyond the window. This will help keep some of the rain out of the top channel (caulk should prevent the rain from penetrating but you don't want water freely pooling up there either)


repiping with copper I need to replace ALL the old galvanized pipe in a two story house with copper. PEX is not code in Chicago. Any tips on running to second story (especially shower) without completely destroying walls? Can I just disconnect the old galv. and leave it in or should I try to cut it out?

It's a challenging job, I would remove all the galvanized pipe if possible. I don't like running into decommissioned wire and pipe when I'm on a job. You have to think about the next guy coming to do work in the future. A tip for making the connections. Get a flame shield and keep a pail of water close by. Also pre-tinning the pipes can be helpful in those really hard to heat places.


Leaking laundry faucet, seems too well attached to pipe to come off The hot water valve for our washer started leaking after we turned it back on after replacing our washer. It probably hadn't been shut in years. If I keep it shut the leak stops, but if it's open there's a ever slight drip right at the stem.

I have done some work with regular faucets before, but this one is different as it doesn't appear to be screwed on? There's exposed threads but the faucet doesn't appear to be screwed to those. I've also heard of a packing nut that I could tighten, but from the look of it most of the apparatus seems pretty stuck in place.

This type of valve can be soldered or screwed on, in your case it was soldered making total replacement more difficult. You need to replace the stem packing.  Shut the water off at the source. remove the handle from the stem. Hold the hex closest  to the wall with a wrench or vice grip pliers, You don't want the pipe to turn, when with a second wrench you unscrew the packing nut. Remove the nut along with any old packing. Bring some of the old packing to your local hardware store to match it for size. Wrap a piece of the packing around the stem in a clockwise direction. Reinstall the packing nut. Reinstall the handle. The nut needs to be tight enough to not leak by the stem, but not so tight that the valve handle is difficult to turn


What kind of electrical connector is this and how do I remove it? I am replacing a bathroom ceiling light fixture. The house is pretty old and has cloth covered wire. The fixture I'm replacing is relatively updated but when I went to remove it, I noticed it was connected to the wires out of the ceiling using some kind of wire joining implement that I've never seen before. I lightly tugged on one  the old black fixture wire and it came right out of this connecting device. The white wire won't budge. Since it was for the old fixture I'm replacing, I cut it.

What is this connector and is there some kind of release button/switch on it that I need to press to disengage the wires?

Pictures are below.

It's a push-in connector. Basically the splice version of a "backstab". Not the best connector, to be sure.

Do not cut.  Firmly grasp the splice connector, then steadily tug and twist the  --

-- Actually, forget that.  The wires in the ceiling are already too old, short and fragile.  Leave the connector alone and cut the modern, plastic black and white wires about 6" from the connector.  If you dislike this plan because you plan to reuse the old lamp, then cut it at the halfway point.

Strip the ends of those wires you just cut, and wire-nut your new fixture to that.

Also these types of connector are single-use, so once you drag a wire out of a void, you have damaged the spring and can't use it again. This is also true even if you use a proper release mechanism.  I would say "just cut" because it leaves the wire stub in the hole, preventing reuse; but wire length is precious and not to be squandered, that's why you have a short-wire problem today.

Note that the above part of my answer violates Code.  The Code answer is the wires in the ceiling are simply too short.  Loosen the cable clamp and see if you can pull extra cable length in. If not, replace the entire cable in the ceiling/wall.  It must have 6" of length beyond the cable clamp, and 3" beyond the ceiling surface.


What should I use to overlay a particle board subfloor in my mobile home? I am buying a mobile home that has a three-quarter inch particle board subfloor. I plan to patch any holes and then overlay the particle board throughout the entire trailer with either plywood or OSB. Given that the new floor will be resting on the existing particle board, what thickness do I need and should I go with plywood or OSB? Don't want to be too cheap but I don't want to overspend either.

If you do in fact have only the 3/4" particle board now, you should not consider it structural. Therefore, I'd use 3/4" (23/32) tongue-and-groove OSB, which is standard as a basic single-layer subfloor in new homes. In areas where you want to install vinyl or other flooring requiring a prepared surface, use 3/4" t&g BC plywood to avoid the need for additional underlayment.

If you actually have MDF (or some other high-performance pressed-particle product), which has more structural integrity, I'd consider a 1/2" or 5/8" BC, with the joints staggered from those of the MDF. You won't save a ton over the OSB (it may actually cost more), but it'll result in less of a height difference and has a nicer finished surface.


How to get a wrench into this location to remove this nut How do I remove the nut from this vertical motorised valve in the following picture:

The valve itself is a few mm next to the pipe and I have tried quite a few tools to remove this and nothing works. I also can't get any tools behind it either so I'm out of ideas.
They somehow built this thing so someone tightened those nuts so they must be able to loosen it's just I can't see how.
The valve here is making a screeching noise at times when opening so I want to replace it.

Remove the valve motor (and housing), then you have access to the fitting.

Possibly you won't need to remove the valve itself, and the noise comes from the motor.


Is this Coleman Recessed Heater Model #69 gas or electric? Is the Coleman Recessed Heater Model# 69 gas or electric?

The AGA logo and the nameplate specs are dead giveaways

This is a gas heater -- the nameplate specs are in BTUs, while an electric unit is specified in watts.  Furthermore, it's AGA certified -- the American Gas Association doesn't deal with electric heaters!


Hanging 10kg/22lbs pulldown projector screen from hollow plasterboard/drywall WITHOUT JOISTS really need some help!

I have a 2.2m long 7ft projector screen around 10kg / 22 lbs. I need to hang from a hollow wall WITHOUT JOISTS.

Bit annoying, but I've got a stud detector and defo no wooden joists in this ceiling. Seems to be suspeded on these thing I imagine as lots of metal detected https://gmceilings.co.uk/mf-ceiling-taunton-somerset/

I've got two of these - they say they are rated for 25KG https://www.amazon.co.uk/gp/product/B01AK6UO2C/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1 but I'm not so sure.

The plan is to hang the screen on these as needed (not permanently up).

The Ceiling is half inch thick.

I need it abou 12" from the wall or I would just affix to corner.

Thanks!

-Peter

the Molly Hollow Metal Cavity Ceiling Spring Toggle Hook M4 x 60 mm  you link is itself "rated" to hold 25 lbs... based on it being metal and an M4 diameter.  It's the drywall that isn't going to hold up to a single molly like that even if it has the finger thing that opens up when behind the wall spreading the load over more area.

if u can't make the joists suspend the load, then what u do is take a piece of wood to your liking...

a 2x3 stud costing $1.98 per 8' if you are really cheap, cut to desired length
a nice piece of 1x4 or 1x6 hardwood cut to desired length
make a metal plate of sufficient area, tap screws into it which will then hold accept threaded hooks to hold the suspended load; a 1/8" thick plate could be least obtrusive.

all depends on what your goal is, permanent or temporary, nice looking or don't care

what u simply want to try to avoid is suspending the load between joists where it's going to pull on the drywall whenever possible.  And when you will be using the strength of the drywall do so over a wide an area as possible and from directly underneath the joists whenever possible.

your 7 foot long projector, get a 7' length of 1x4 hardwood, use wall anchors but use many staggered every 4" or so because you would not be drilling up into joists... the drywall is going to support the load of the 1x6 by 7' long.  And the hardwood then supports the weight of projector via however you hang it.

Take it down, spackle the molly holes.  you could also use mirror adhesive or any kind of drywall adhesive and glue the entire 1x4 by 7' but that would make that wood a permanent fixture on the ceiling... might look ok if painted white left there indefinitely (hang some plants or something).


Why does my fluoresent light power line show 15 volts with switch on and off? I have a double circline light fixture in the kitchen.  I replaced the ballast resistor 3 years ago.  The lights went out again a day ago, so I replaced the bulbs.  Still no light.

I figured that left the ballast resistor, though it seems strange it went so fast when apparently the original from the seventies lasted until 3 years ago.  Suspecting something was up, after I took out the ballast resister I measured the power line with a digital multimeter.  It showed 15 volts with the switch on and off.

If one of the readings is stray voltage, how do I correct for that with a digital voltmeter.  I think the light is on a 30 amp line, and my digital voltmeter only measures AC current up to 10 amps.

Are you sure that it's a ballast resistor and not a transformer? A resistor would be extremely inefficient, obviating any benefit in efficiency of a fluorescent lamp.
A DVM has a high input impedance and will pick up stray voltage coupled by wiring capacitance even when the switch is off. There is no need to measure the voltage when the light is switched off.
N.B. Do not measure the current across the mains with the meter. If you put the meter in series with the lamp, it should draw no more than 1 ampere, but do not put the meter, in current mode, directly across the line!

If you're having frequent issues with the fixture, replace it with a surface-mount LED fixture. You can find theses in different color temperatures from 2,700 K (co0lor similar to incandescent) to 6,000 K (actinic blue-white). LED lamps should (at least theoretically), last many years more than fluorescents. (The link is just an example.)


PEX for hot water tank I was just replacing an electrical hot water tank.

Had to call a plumber because I didn't fancy my soldering skills on something that could flood the house. The plumber simply cut off the old copper lines (after the shutoff valve) and used pex to connect the tank and as a vent pipe.

Apart from if I'd known you could do that I would have done it myself - is this OK?
Seems to have been tightened with proper synch connectors and it certainly works.

PEX is usually rated at 180° F (82° C) -- it should say on the side of the pipe what the actual rating is. As long as your water heater temperature is below that, you're fine.

From wikipedia:

  There are two seemingly conflicting safety issues around water heater temperature—the risk of scalding from excessively hot water greater than 55 °C (131 °F), and the risk of incubating bacteria colonies, particularly Legionella, in water that is not hot enough to kill them. Both risks are potentially life threatening and are balanced by setting the water heater's thermostat to at least 54.4 °C (130 °F). The European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease recommend that hot water should be stored at 60 °C (140 °F) and distributed such that a temperature of at least 50 °C and preferably 55 °C is achieved within one minute at outlets.

As @Michael points out, a T&P safety valve is rated to go off at 210°F (100°C), so if something does go wrong and your water heater overheats, there is a possibility the PEX will fail. If the PEX does fail, it almost certainly will happen right above the tank (which will be the hottest place, obviously). It will also serve somewhat the same job as the T&P valve, except that a T&P valve will close once the temperature/pressure has lowered, while a burst pipe will just keep gushing water until someone shuts off the supply.

The chances of water heater overheating like this are quite low: electrical heaters have thermal fuses in them that serve as an electronic safety (very hard to find the temperature rating of these: seems like it's anywhere from 167 to 210°F). In addition, the electronics are pretty reliable, and just very unlikely to fail "on", and without drawing too much current that would cause the breaker to trip.


Is there any level of radon in the home that is *immediately* dangerous? I ask because when I purchased my home the level was 19 pCi/L, and on a recent retest it is 27.8 pCi/L.  I plan on for sure getting this fixed within a month, but I'm wondering if there's any reason to make it priority to get it done sooner.  Most of the statistics, etc. on the danger talk about the effects over a lifetime, how much radon would it take for there to be an immediate danger to be living in the house?

According to this Radon Dose Calculator, if you are exposed to 30 pCi/L the dose rate is 6.275 µSv/h.  Multiply by 30 days and 24 hrs/day to get 4500 µSv, or 4.5 mSv dose over 30 days.

Wikipedia suggests that is similar a CT scan (which is a significant dose).  You are probably not in the house 24 hours a day so you could adjust the numbers downward.

Here's another nice visualization of different doses.


I replaced my bathroom exhaust fan switch with a countdown switch I replaced the switch of the AirKing bathroom exhaust fan with a countdown timer.
However, even the timer is working as expected, I noticed a drop in the fan power, it does not blow as much air as it used to blow. So, I think the issue may be related with the output of the countdown timer. The manual (see below) mentions an output of 500W. But, I am not sure what is the wattage of the fan. Would you agree that this is the reason for the drop of power? Can you recommend me what should I look for when buying the right countdown timer for a exhaust fan?

This switch is for use with halogen or incandescent light fixtures only and is not designed for motor loads. Motors do screwy things to electronic switches. Get a simple spring operated countdown timer.


Something wrong with electrical outlet or outlet installation? I installed an electrical outlet using the same line that feeds an mini-split A/C.

Once I installed it, I tested it with a regular electric drill that I have. The weird thing is that the electric sparks coming from the drill are much stronger that with any other outlet in the house. The drill seemed to have too much power. I was worried the drill was going to burn out.

With any other receptacle, the drill shows minimal electric sparks.

I've included a picture:

What could the issue be?

Thanks.

There are many reasons not to "tap" random lines going to fixed appliances.

#1.  They may be 240V!

Indeed, since the tool performance is not as you expect, you have assuredly tapped a 240V line.

One of the problems is that in residential wiring, they often use /2 cable to wire the 240V appliance.  In /2 cable, one of the wires is white, that is simply how /2 cable is made.  It is allowed for 240V circuits if the ends of the wires are re-marked a color with tape or paint, however that is often skipped because the use is "obvious" (e.g. going into a 240V breaker or to an appliance whose nameplate plainly says 240V).  In any case, that marking won't exist mid-cable so you don't get it if you tap it.  Don't tap cable.

As R.M.E. notes in comments, even if you figure out how to get 120 off a 240 line, you are drawing unevenly.  And you might also have to bootleg ground to do that.  Bootlegging ground renders unsafe your entire grounding system - all through the house.

#2 there is no legal/safe way to "tap" cable

The proper way to tap a length of cable is to add a junction box where needed, cut the cable 10" past the entry to the new box (leaving the other cable 10" short) then either replace the short cable entirely, or install a second junction box 20" away simply for the splice.  Obviously this includes a strategic choice of which half of the cable to replace.

There is no legal way to tap cable that doesn't have 18" of slack.  So you are doing something seriously horky and hacked.

Even a temporary inline tap means you have torn away the insulation.  You are not allowed to then bury that now-damaged cable in the wall.

#3 Dedicated circuits don't have capacity to spare

When you have a large hardwired appliance like a water heater, stove, air conditioner, etc. on a dedicated circuit, that circuit is usually sized to supply that appliance alone.  Suppose you have a 15A air conditioner.  It must be derated to 125% for a continuous load, so 18.75 amps.  That on a 20A circuit leaves only 1.25A to spare.   It could run an LED porch light, that's about it.

Further, if the hardwired loads are more than half of circuit capacity, you are not allowed to put receptacles on the circuit at all.

#4 It may not protect your socket (too large a breaker)

Often, a dedicated line is a larger amperage (i.e. 30A) that is not legal to connect a common 15/20A receptacle.

Any 20A receptacle(s)  requires a 20A breaker.
a single 15A receptacle requires a 15A breaker.
the very common double 15A receptacles can take a 15A or 20A breaker.

Even worse, as Ed Beal notes in comments, the breaker/wire combination may have been engineered for a specific load. It is not properly protected on a different load.

The right way.

You use "permanent" wiring methods so the appliance is no longer connected, and your receptacles are.   If it's on too large a breaker, or the wrong voltage, you also move the wires to a correct sized breaker.

When you're all done, you rewire it back.

For instance I needed to hook up a 240V heater temporarily.  It is listed to install on a 30A circuit.  I followed the A/C cable (which fortunately was in conduit) and found an intermediate junction box, where they had graciously left me 18" of slack.  Snip.  I capped the wires to the A/C unit.  Then I spliced the wires from my heater into the supply (10AWG since it is a 30A circuit).   When I was done, I removed the heater cable, capped the knockout, and re-nutted the supply wires back to the A/C.


PIR motion sensor interference by nearby CFL I have a Passive Infrared Motion Detector (this one) in my walk-in closet that turns on the light when someone walks in.  This setup has been working fine for many years.

Outside of the closet is my wife's make-up area that was illuminated by a 75W incandescent ceiling light controlled by an on/off switch.  No electronics here.

Because the 75W bulb was not bright enough, I replaced it with a 42W Compact Fluorescent Light whith a 150W equivalency rating.  Now, when she walks into the closet when the CFL on, the light in the closet stays off.  She has turn off the CFL for the motion sensor to work.  When she turns the CFL back on, the light in the closet eventually times out like normal.

I cannot replace the CFL with a 150W incandescent bulb, since the bulb fitting is rated 100W max and 150W equivalent LEDS are too expensive (and big).

Any ideas?

If your wife's makeup area is now too bright for the closet light to turn on, you can use a piece of window tint if you have it or perhaps even a piece of dark panty hose (maybe your wife has an old pair) to cover the sensor area. Dark Panty hose is dark enough and yet has enough fine holes to allow it to attenuate the light (like sunglasses).


How to stop metal bar from rotating? I made a DIY pull up bar by putting a barbell onto a barbell holder, however it rotates a bit when hanging on.
How can I stop it from rotating given this set up?
(There's only 1 barbell in my set up)

The bar is rotating because there is little friction between the bar and your supports.  Glue some soft rubber strips on the supports where the bar sits and you'll be all set.
On a side note, one limitation a lot of people have in strength training is in their grip strength.  This is manifest by the ubiquitous use of lifting straps.  If your grip is strong you won't need to prevent the bar from rolling.  That said, to each his own.


Identifying live and neutral wire of an old lamp So I have this old wall lamp with a different color code that I'm used to: There are 2 brown wires welded together and a separate dark brown wire. As seen on the picture the 2 brown wires leads to the light bulbs and at the connector / switch it says "2A / 250V" meanwhile at the dark brown wire it says "A1 / 31". The thread on the picture is the switch, to be pulled up and down. I'm not sure how to go about it and I rather not risk it so I turn to your wisdom instead!

Unscrew the bulbs and see which wire is connected to the side-contact that contacts the thread of the bulb using a continuity tester. That one is the wire you want to be the neutral.

That way the live contact is buried deep within the socket and harder to reach by inquisitive fingers.

The dark brown looks to be the ground connection. Check that it has continuity to the metal housing to verify.


How to Mate Old Subfloor with New Plywood? I'm replacing the floor in a ground floor bathroom. How do I mate the old plywood subfloor with the new one? I plan on leaving a gap between the subfloor and the sole plate around the perimeter of the room to allow for the plywood's expansion and contraction but, what do I do where it meets the doorway. Do I need a tight fit with the plywood in the doorway or do I leave a gap?

I'll install blocking and sister the last joist.

Do I need to cut the old subfloor back so that half a joist width is exposed in the doorway, so that the old and new plywood are fastened to the same joist? I plan to sister the last joist. There will be travertine on cement board over the subflooring.

I see you have 3 layers of flooring that was under the old tile. The top layer I see the cement board, under that the underlayment, and under that on top of the joists, the subfloor.

To get a good tie in to the existing, use a right angle grinder or circular saw with the proper blade, and cut back the cement backer about an inch away from tile floor coming through the doorway from the other room. If it is not tile, like I think it is and there is a joint somewhere close to what I described earlier, remove the material up to that joint then. That looks like it may leave about 3-4 inches of plywood underlayment exposed after the cement board is cut and removed. Next set the circular saw to depth for the thickness of the plywood underlayment and make a cut about 1 1/2-2" away from the cement board, finish the cut to the side of the door rough opening with a multimaster or reciprocating saw if you can control the depth of cut, and remove that small piece. Do nothing with the subfloor. Add screws along the edge of underlayment to secure it to the subfloor. Add the ledgers/sister joist, the subfloor. When cutting the underlayment, make sure it is one piece going into the doorway and out into the bathroom a ways so the joints in the underlayment and subfloor do not line up. Use screws to hold the underlayment to the subfloor, use construction adhesive if you choose to as well. The screws go in at 4-6" on the perimeter, 8-10" in both directions in the middle. Do not concern yourself with those screws going into the joists, it is better if they do not. 1 1/2" or so long screws will do well there.

I typically gap all my plywood that is not T&G about 1/8" on all edges. when it is T&G, I still gap the ends 1/8"


Can I repair a plaster ceiling with drywall? I had a leak from my upstairs bathroom that came into my kitchen.  The repairs for the leak can be done through the kitchen ceiling where the damage is.  My ceiling is plaster that has been wallpapered to look like a tin ceiling.  All of this needs to be replaced.  The insurance company gave me money for a drywall repair to my ceiling.  Can that be done, or does it have to be plaster? I plan to have it repapered.

Depending on the thickness of the existing plaster, a drywall patch with suitable support behind it (with "mud" or patching compound over it to merge the edges with existing plaster and achieve a smooth surface) may be a perfectly reasonable solution. Getting it really smooth and level so the patch doesn't "telegraph" through the wallpaper will take some work and patience; sand, mud, sand, mud, repeat until a raking light shows no irregularities from any direction.


Is it possible to convert a truss attic into living space? What are some options for converting a trussed roof into living space?

My understanding (please correct me if I am wrong) is that the following needs to be taken into consideration:

proper floor joists need to be installed/sistered.
Knee wall supports need to sufficiently replace the webbings of the truss to support the roof
space needs to be considered to accommodate proper insulation between the living space and the roof where it contacts

I've seen a lot of systems/contractors that seem to specialize in this in the UK, but I can't seem to find much information for North America. Not sure why that is.

Has anyone done this? Is it at all a DIY proposition (providing proper engineering documents are approved)?

UPDATE:

My purely hypothetical method at this point (how far off base am I?):

install 12" floor joists 16" OC
install kneewall between current 2x4 truss 'rafters' and new floor joists.
install top cross-bracing/collar tie (not sure how much/spacing)
cut joist webbing (!?)
between knee wall peak, install 12" 'rafters'...these wouldn't be load bearing but act as spacers for insulation and interior ceiling.
leave gap between original 2x4 rafters and sheathing for ventilation
insulate remainder 10" of rafters and knee wall

It seems that the above plan would basically be converting the current truss system into a box storage truss, albeit with larger floor joists.

Am I in the ballpark? Again, I'd definitely be consulting with an engineer to do it right. Just trying to get an idea of what it would take.

With the above, I think I'd need to pull off the first layer of sheathing on one side of the roof to bring in the joists. If I had a load-bearing wall mid-span, could one bring up half-joists into the attic directly (since these joists are purely for floor support while the original 2x4's are acting as the ties?)

UPDATE 2:

Some more details of this particular example:

The attic space is 22' on the side parallel to the trusses (28' on the other side). It's a 12/12 roof, so that's a good 11' at the ridge, which even with new floor joists and a 5' knee wall should be plenty of room for a nice space.

The trusses are double cantilever style:

I also came across this in Fine Homebuilding on using welded steel as part of the rafter structure. More applicable for creating cathedral ceilings but thought it was interesting:

http://www.finehomebuilding.com/how-to/articles/framing-cathedral-ceilings-with-steel-sandwich.aspx?ac=ts&ra=fp

It is definitely possible. My uncle has had this done in his loft. They had to reinforce the trusses with large pieces of wood, but they were single rather than double cantilever so it was easier.

Perhaps it's worth getting some quotes from professionals or hiring an advisor, as they'll be able to give you an idea of what would be involved and the complexity of the task even if you don't use their services.


Can you glue vinyl cove base directly to drywall? I'm installing this vinyl cove base in my garage.
Garage walls currently do not have any kind of baseboards just drywall to the concrete.
Can I glue the cove base direct to the drywall or should I first install baseboards for more support?

Well you can glue them - that is really the only way to install them.   However I have redone quite a few garages...
I would just install azek or PVC trim boards - that's it.   Paint them whatever color you want and you install with finishing nails and don't have to worry about water (if done right they can protect your drywall from water on floor) and don't have to worry about pealing or replacing (you just repaint).
Not to dog vinyl cove (I have installed it commercially) but it really isn't a "home" product and it certainly shouldn't be used in areas that will see high temp and moisture changes.


Switching new dimmer for old dimmer My new dimmer for LED lighting has four wires: one black, one red, one red/white and a green ground. The old dimmer only has three wires: a single red, single black and green ground. This is also going to be a three way. How do I install?

Assuming the dimmer is similar to the Lutron dimmer in this question:
The new dimmer can be used as a regular switch or a 3-way switch.
For a regular switch, which it sounds like the way your old dimmer was connected:

Black - Hot
Red - Switched Hot
Green - Ground
Red/White - Not used - cap with a wire nut

For a 3-way switch:

Black - Hot
Red - Switched Hot/Traveler 1
Red/White - Switched Hot/Traveler 2
Green - Ground

The second switch for a 3-way setup should be a regular switch, not another dimmer.
Wiring a 3-way switch can be a bit confusing. Search for other information on that (plenty on DIY StackExchange, or Google it) and then just treat the dimmer as one of the 3-way switches.


Would it be appropriate to sand a floor between coats of poly with a handheld orbital sander? Very closely related: How should I sand before the final coat of polyurethane?

However, I'm not asking for a how-to or which is the preferred tool/method but rather one specific tool and if it's an "ok" approach to take.

Assuming I already owned a 5" random orbital sander (similar to below example image), would it be realistic to use it with 220+ grit sandpaper rather than a "full-fledged" floor buffer, at least to the level where I can use it between a few coats of poly and still achieve a good finish on the final coat?
I'm not really asking if it's necessarily  practical, but more as a cost saver while also being able to achieve a decent result (plus I don't have the level of experience with the larger equipment as I'd like/be comfortable with).

From what I've been reading, poly doesn't seem to need a whole lot of intense sanding between layers and just a little roughing up for subsequent layers (by all means correct my if I'm wrong here - would rather be berated online than ruin a perfectly good floor).

I know it'll take longer simply due to size, but I'm only looking at a couple hundred square feet anyway, nothing overly large.

I had two floors to do once and between coats I used a broom with 3 bits of fine sanding paper taped to the broom head - cheap, cheerful and effective...

Also, had to punch down the floor brads (nails) so they were below the surface...

Those floors came up magic but also vacuumed after sanding to remove the dust...


How to shave down or flatten - surface concrete of garage - rain water leaking in under door I have a garage floor - the floor in the garage has sunken leaving the area at the exterior foundation wall - Entrance - to sit up higher like a nice ramp which makes a perfect Rain Water collection scoop to wonderfully force the water under the door and into the garage (if anyone wanted to know how that was done - there is your answer.) So I am looking for a way to fix this problem - I thought about grinding and shaving at the Garage Floor to Drive way to even it out with the garage floor and prevent it from acting like a funnel - I have done all kinds of things to seal the door - they have helped reduce the pond in the garage but not end the flow..

Here is a drawing :

Actual Picture - May not show it correctly maybe I should have used a level or an angle gauge to display the angle of the slant..

When faced with a similar problem I opted to cut the blue part about 4 inches away from the garage slab, break and remove the concrete, and put in a pre fabricated French drain. The cutting was done with an old skilsaw and $15 diamond blade, and busting was with hand tools. About a 1 day project.


Water heater tank - the upper of burner is rusty - will it leak soon? I found the rusty and drip on burner, please refer the pic. My question is: will it leak soon from the rusty place? It's really scare me when I saw it. And, the water heater is almost 20 years I think.
Thanks, and appreciate your answer.

Water Heaters that you can purchase today usually have a warranty from the manufacturer. I think the average warranty is about 6-8 years. You can find ones for 8-12 years, but you will pay much more.
You can estimate fairly accurately the life-span of a water heater by looking at the warranty. This is not always true, but it's a good way to get reasonable life-span.
I believe any water heater that makes it past the 10-12 year mark is close to replacement. There are the rare ones such as your's, that should be included in the Guinness Book of Records. And although you may get some more years of service out of it you would be wise to start considering a replacement.
Looking at your photo the rust means that water has already leaked on the bottom. There is also sign's of pitted metal which means the water has been there for awhile. If it's not leaking alot now than it will be in the near future.
Yes. It's time for a new water heater.


Breakers protect wires.. doesn't 83% derating violate it? For homeowners, do you need to follow the derating rule? Illustration:

https://www.youtube.com/watch?v=OLIHEiiY_Rs

The point is conductors can be used that is 83% of the supposed size compared to service conductor.

But in the above example. What if the residential houses have so many guests and the wire amperage reach 190A. Then since the breaker is still 200A, and the wire is only rated at 175A (or 83%). Then the wire can burn before the breaker trips. So isn't the 83% kinda dangerous for those with many guests? The philosophy is the breaker should protect the wire. But in this case. It can't anymore.

For my actual use. I have service entrance breaker of 150A. 38mm^2 is within the 83% rule (according to Harper in related Can I do a 125A subpanel feeder with slightly-larger-than-#3 wire?).  But 38mm^2 is only 122A max at 75C. What if my house load is 130A (with many guests), then the 38mm^2 wire can burn before the 150A breaker trips.

It gets kind of weird, but in general residential loads just don't have high enough duty cycle for it to be a concern.  Add up every load in your house, and I doubt you'll be able to draw the full 200 amps (48kw assuming 240V service) for any length of time, even with a house full of guests.  Indeed, I have 200amp service (48kw), but the transformer that feeds my house and about 5 others is only rated to 25kw. The power company asked what loads I was going to power with an upgraded service, and deemed it unlikely that I and all my neighbors would be using more that 25kw for more than a few seconds at a time.

Ampacity charts also have a significant safety margin.  Drawing more than 175A over a 2/0 wire will get things hotter than desired, but won't cause the cable or its insulating jacket to break down.

Commercial/Industrial loads are different.  The Code assume that the duty cycle of devices is much higher, and therefore commercial/industrial rated breakers actually trip at 80% of their load rating for continuous draws.  (They allow spikes above that for shorter lengths of time.)


Installing 6-20R receptacle in the kitchen (Ontario) Was thinking of installing one in order to take advantage of 240V countertop appliances (i.e. a heavy-duty induction cooktop)

Are there any specific Canadian electrical code requirements for installing heavy-duty receptacles in your kitchen?

I believe CEC does the same as NEC regarding you must have a recep within 2' of anywhere along the back edge of kitchen counters (following the wall). That's because kitchen appliances have 2' cords.  240V receps don't count for this, so don't convert a receptacle unless you're sure you're covered.

I don't believe CEC requires GFCI protection on 240V circuits (we add that in 2020 NEC), but that's something you'll really, really want for countertop appliances if it's within 6' of a sink.  On a 240V circuit, GFCI can only be done at the breaker.


How can I secure an outward door swing to be safe inside without drilling holes? I want to feel safe inside a room that swings door outward. How do I secure a outward door swing to be safe inside at night without drilling a hole into the wood. is there a portable outward swing long available for sale? thanks !

I saw a device that looked much like a key hole in a steel plate. It slipped over the doorknob and it’s weight held it in place. I thought that was a good idea, even made out of 1/2” plywood if there was a few inches above and below it would be as strong as most cheap lock sets.
The keyhole looked like it was made with 2 different sized hole saws one that was larger than the handle and one just slightly larger than the shaft if you pulled on the door it did not move much. That would be something that could be made but I have not seen a commercial one.


How do I glue glass top to a wooden base I made a log table and now I'm trying to put a glass top as you can see in the picture.

The issue is that the glass top is not sticking to the log. I tried various things such as clear adhesive bumper pads etc from Lowes but nothing is working. The bond is not strong enough and I have two seven years old who keep bumping into the table.

Does anyone know what I should be using to glue the glass top to the top of the log.

Suction cups are used with success in this situation.  Search for "glass table suction cups".  The cups have a small cylindrical nub that sits in a hole you will have to drill for each cup. You should only need about four.  With the suction cups, the table would be secure, would have some (minimal) give when struck, and would be easy to replace.


Gas line tape overlap to cover all threads? I am using gas line tape and it says to make a minimum of 4 wraps. The tape is 1/2" wide but the threads on the pipe are like 3/4" to 1" long. Is it correct to wrap only the section in the middle or should I cover all the threads by overlapping the tape and work my way from the end to the start of the threads, and then back again? I tried overlapping but maybe I did it wrong because I wound up with a fat area in the middle.

I wrap so that I taper the tape thickness down towards the starting threads.
Also I wrap so that the tape is not unwound by the screwing in of the threads into the hole.


tripping circuit breaker My 15 amp circuit breaker for 2 bedrooms trips whenever either of the overhead lights are turned on but also if more than a couple of low amperage things are used in any of the receptacles (radio, low voltage light). I assumed the circuit breaker was the problem so I traded circuit breaker locations. The new circuit breaker had the same problem. The home is about 1 year old, it was professionally wired and it is not a GFI circuit.

The only real solution here is to actually measure the amount of current being drawn by the circuit.

This could be done by any number of jury-rigged methods using a multi-meter. But the safest, most effective would be to use a "clamp-amp" or "amprobe" style meter:

If the meter shows a load around the rating of the breaker (15 A), then you need to remove some of the loads on the circuit, and or have the rooms split into two circuits.

If the meter shows a load far below 15 A, then it's likely that the breaker is faulty and needs to be replaced.


Can anyone identify this old wiring in my walls? In several of the rooms of the house I moved into last year (built 1973, USA), there are blank wall plates. I've removed a few to investigate and found somehting similar to the below pictures each time: a loop of what appears to be thick brown electrical cable, accompanied by a foot or so of thin 2-conductor black cable that is either insulated with rubber or a very flexible plastic, and covered in orange muck.

I've given the large loop a god tug and it doesn't appear to be an off-cut tucked back up into the wall. If it is, it's jammed in there pretty good.

Neither appears to carry any voltage according to a NCV tester, and it doesn't resemble the mains wiring in any of the live outlets or switches (which is all white plastic NMC and generally a bit thinner than the thick brown wire here).

I'm not intending to do anything with it at this point, just curious as to what it is/was.

Partial answer: the larger cable is Belden 8290 shielded twin lead TV antenna cable, which was introduced the 1960s and so is probably original to the house.
It's been literally years since I posted this question so in all likelihood nobody will happen upon this, but while working in my attic today I uncovered an old UHF/VHF antenna that was laying on the rafters and buried by the blown cellulose insulation. After digging it out a bit I immediately recognized the wire it was connected to as my mystery large wire and could finally get a good look at it.
There was no sign of the smaller wire in the attic so what that was used for remains anybody's guess.


30V showing on terminal of 3 way switch when switched off I have a 3 way switch I am replacing, and found that while testing the old switch, one of the terminals is showing 30v when it's switched off and should be showing 0v. The other terminal correctly shows no voltage when switched off. The situation persisted when I replaced the switch with a new one, so it wasn't a problem with the unit itself, and otherwise the other terminals show correct voltage (and that one showing 30v when off shows 120v when on). I'm assuming that means that I have current coming from somewhere further up the circuit but I'm not sure where it would be coming from. Is this a dangerous situation to be in or can I safely ignore it?

This sounds like phantom voltage. Most meters are high impedance and will show a voltage on a wire that has voltage close to it.
If everything is working properly with your switches there is nothing to worry about.
Phantom voltage can be found all over your home and it is not dangerous.
If your switches are working you can ignore it.


How can I frame this area of my basement wall around my water main? I have started the process of framing my basement, but I've hit a bit of a snag as I'm not sure how exactly to frame around our water main. My original idea was to frame two walls (floor to joists) on each side, and fill the gap between them with a knee-wall of sorts, but I'm not sure that this would meet code.

I've created a rough but fairly accurate diagram of the area that should help.

The main enters approximately 6 ft from the floor, turns 90-degrees upward, enters a main cutoff followed by a regulator, continues to the height of the floor joists, where it turns 90-degrees again and runs perpendicular to the joists. The entire vertical assembly is less than a 1/2 inch away from the concrete wall.

I'm open to framing a vertical chase, however I've not been able to find any information on how to do this properly and to code. In addition, the water pipes run below the joists, and I do not intend to finish the ceiling at this time. I would like to avoid moving the wall out from the concrete wall, as I would like to keep as much usable space in this area as possible. I would also be okay with adding additional blocking (can this just be nailed upward into the blocking I've already added?) to lower a continuous header 1.5 inches, but it would require notching the back side with no way to add the appropriate strapping.

I would appreciate any insight in handling this framing design, and would prefer that any answers meet code (as there will be an inspection later). Thank you in advance.

Answered

If you header is a 2x4, just run it in the joist bay for that wall.


Identifying these light switches I am working on a Home Automation system that I inherited from someone who didn't really know what he was doing. There are dozens of light circuits, but only three of them can be controlled from the system (Leviton/HAI OmniPro 2).

Here is a picture of four of the switches:

The leftmost switch works, and the other three in the picture do not.

I know that the left switch is a Leviton model that speaks HLC, Leviton's proprietary extension on top of UPB.  However, I cannot figure out the model (and capabilities) of the other switches.

Can anyone tell me what they are (brand, model, etc) and/or what protocols they support?

These are really old HAI switches (from before Leviton bought them) which use the ALC protocol over separate signaling wires.

I finally found someone who could tell me that the original switches were put in around 2005, so I used The Wayback Machine to look at HAI's website as it appeared at that time. From there, I found pictures that match these switches perfectly.

UPDATE: I finally got into the controller cabinet for the system and discovered that it has an ALC controller already hooked up with lots of wires that appear to go to these old switches all over the building. It appears that we should already be able to control the old switches from the system because of this board, so I'm guessing that something is just misconfigured in the settings.


Is it safe to simply replace a heating element in an electric water heater? The bottom element in my water heater burned up. I took the bottom panel off, and everything inside was scorched - the insulation, the plastic cover, the thermostat - even the edges of the panel.  The thermostat still seemed to work, so I just replaced the element - and it runs like a champ now.  Can the scorching cause any issues?

Possibly, but without seeing the extent of the damage no one will be able to tell for sure.

Given that you have already replaced the element I'd keep a close eye on the heater for a few days to make sure that there are no problems.

Did you clean everything and check for further damage before you reassembled the heater?


How can I route the shower plumbing back into the wall? I have purchased an exposed shower valve similar to this for a ground-floor shower room in my home.

I would like this connected to a ceiling mounted rainfall shower like this.

So I need to be able to route the shower valve outlet back into the wall that the valve is fixed to (and then the pipe will go up behind the wall, into the first-floor floor cavity and then back down through the ground-floor ceiling.

But I am not sure what connector to use to attach to the shower valve outlet to route it back through the wall. Any advice?

I have found this but I'm not sure if this is what I need.

That type of control valve is intended for the pipe to stay inside the shower enclosure.  Why not just run it up the wall to an elbow and then across the ceiling to another elbow for the showerhead?

Otherwise you would need a control intended for all the plumbing to be inside the wall like this:

There are a number of accessory finishes for the handle and trim.


Is NM (Romex) wiring ok for a shop wired in 2006? The shop building on a property I want to buy was built in 2005 but not wired until 2006. The building is metal with a wood framed interior office and bathroom.

It appears to be wired with Romex and has been carefully structured with the outlets at the 5' high purlin. All of the other runs are taken up to the 10' or higher to go across and appear to be captured with clamps or plastic ties to the metal structure and protected by the material similar to running down a wood post, etc. The load balance appears to be ok, with separate circuits for the items that require them, etc.

On the area above the office, the wires are stapled to the floor along the steel wall, but the floor is storage area.

Is this an acceptable situation for an outbuilding of this type? Does it matter whether or not the proposed use of the building is as a shop, or for storage, or for animals or a combination thereof?

I am wondering what would be necessary to fix it if it is not ok for some identified use. For example, could the romex be rerun in plastic conduit or raceways anything like that to make it acceptable if it is not ok as is.

Update: I am so sorry I left this info off - this is an outbuilding on an acreage with a separate house with attached garage, not commercial. This building is a playroom/shop/horse stable/whatever building. I  don't know exactly how it will be used yet. I expect that the building is not to code, but I don't know. It looks like someone tried pretty hard to get it right. No one seems to know who did the work, nor how many owners ago. The building has water, electrical 125 amp service panel tied to the main house (outside of the house not in its panel. There is a breaker in the panel for the house and another for this special use building, both served by the same meter although separate meters could be installed easily. The building has a concrete foundation with water and sewer plumbing installed in the floor. It is not insulated except the office and bathroom 20 x 8 is insulated, heated with space heater and air conditioned. It also has a water heater (small)).

Determining whether NM cabling is permissible can be surprisingly difficult.

In my opinion, if this is an outbuilding to a residence, it's cut and dried:

  334.10 Uses Permitted. Type NM, Type NMC, and Type
  NMS cables shall be permitted to be used in the following:

  (1) One- and two-family dwellings and their attached or
  detached garages, and their storage buildings.

As long as you don't go afoul of 334.12 Uses Not Permitted (service conductors, embed in concrete, wet locations, etc.) NM is OK for single family dwellings, garages, outbuildings.

However, in reality there can be complications.  Again in my opinion there should not be in this simple case, but often there are complications, disputes, disagreements, etc.  For other than single family dwellings / outbuildings, the actual rules are convoluted involving building code construction type classifications, occupancy classifications, and the NEC.  Electricians, engineers, architects, and inspectors trip up on and argue over this stuff all the time.

In your situation, my concerns would be

safety
issues with buyer's inspection when you sell in the future

With respect to safety, properly installed, NM in a metal building is code compliant and generally safe, there's no reason for concern just because there's NM.  If it isn't installed in a manner such that it's protected from the sharp edges of the metal, that can be a concern.  The stuff that's stapled to the floor that's being used for storage sounds like a legitimate concern, but should be fairly easy to correct.

With respect to a future sale, since the NM is code compliant, you shouldn't have to worry about much.  You only have to worry about a future home inspector, working for a prospective buyer, that doesn't understand the rules.  The buyer's home inspector may think NM is not permitted in metal buildings and put that on his inspection report for the buyer.

If that happens, you can only try to refute the buyer's inspection report.  You could show them the applicable code section.  You could have your own inspector or engineer write up a formal report explaining why NM is OK.  You also may be able to refer to the permit and inspection records for the property with the local code enforcement.


Can I combine 1/2" and 3/8" plywood for a total of 7/8" subfloor for laying a hardwood floor? We have some old flooring that comes to a total (flooring and planks) of 1 5/8" from the top of the joists. I want to add a new section of flooring (this one) beside it, and am trying to get them to be as close as possible in height.

The planks in the section I am replacing are too far gone to be used, I have to replace them.

So my question is, for this particular floor (or flooring like it) can I combine 1/2" and 3/8" plywood for a total of 7/8" sublfoor? This was I can lay the 3/4" flooring on top and hit the 1 5/8" thickness I am looking for.

Our floor joists are 24" on center, if that helps.

Thanks!

Structurally, there is nothing wrong with your plan.  But I suspect your floor might be prone to squeaking due to having 2 layers of plywood rubbing each other.  Gluing them together will prevent the squeaking.  But gluing large pieces isn't that practical thus a less reliable option would be putting lots of screws to keep the 2 together.

That being said, don't you want to put an underlayment between the plywood and the new flooring?  That serves as a cushion, moisture barrier, and help w/ the sound isolation.  Take that in account.  It is usually 2-3mm thick.

Would 3/4" plywood plus the pad be close enough to your existing floor?


Multiple anchors and weight dispersion I have a large entertainment center that needs to be mounted to 5/8" drywall with metal studs. The entertainment center weighs about 180lbs by itself. In addition, I'll have a tv flush mounted, pictures, books, and surround speakers on/in the entertainment center. I plan on using strap toggles for all of the anchor points. There are 6 brackets holding the entertainment center to the wall, with two anchor points (screws) holding each bracket in. My question is; if I use toggle straps for each anchor point (12 in total), and each toggle strap is rated to hold up to 70lbs; will that be enough to hold everything? In other words, will the weight be dispersed across all the toggle straps, so that each is holding well less than 70lbs? ...Also, should I be concerned about the structural integrity of the wall? There won't be much weight coming out from the wall; no swivel mount, just shelves that are about 12 inches deep; so we're talking mostly shear force.

So this entertainment center is actually all hanging from the wall, not sitting on the floor and anchored to the wall to protect from tip-over? If so, given the weight (perhaps 250 lbs. but the time you are done with everything), I would NOT rely on drywall anchors of any type but would much prefer to anchor directly into the metal studs. Getting into metal studs is not as easy as wood studs (e.g., 2x4s) but it can be done and is quite secure. One method is to use some wood (either a rectangle of plywood or two strips of lumber) and secure that wood to multiple studs and then you can use screws to hang pretty much anything on the wood. That is routine for telephone/network equipment (not because of weight but in order to have a large area to connect things to, many of which are too narrow to necessarily hit any studs for mounting) and will work quite well here too. As far as "looks", if some of the wood will be visible, paint or stain it to match the entertainment center and nobody will notice.

If the anchoring of the entertainment center is only to prevent tipping over, a few ordinary anchors will do just fine, even if they can't hold the full weight (because they don't need to).


Who do I call to approve minor interior structural changes to my house? I want to knock down an interior wall in my house and make a dropped ceiling flush with the remainder of the room. It should be a fairly straightforward home improvement project that I am quite sure I can handle, however I would like to be totally certain and get a structural engineer to sign off. I would of course pay for his or her time.

Is it common for people to do? Who do I actually call? I don't think I should call a contractor because I want to do the work myself, but I want to make sure that what I plan to do is above board.

You should be able to hire a structural engineer for consultation on your project. Find someone who does residential jobs. I did something similar for a remodeling project. The cost probably varies but the guy I work with is $180/hour. If you have to file a building permit you will have to do some kind of structural drawing showing the alteration and have the engineer put his seal on it indicating that he approves the plan.