New electrical circuit - requesting assistance

What about some kind of smart device that the wife can turn on from the kitchen to let me know that dinner's ready? :-)

You're right.

Also he may have, or put in later, barrels of beer in the basement so he should put in a hose to take that straight to the shed. He'd have the only shed on the block with beer on tap.

In that case, the beer tap is even more important.

Easy to do with Smart Plugs or X10 devices. I had a wireless intercom in a detached garage as well as a light on and X10 plug. .

May be possible to swap breakers for half size. Depends on what you have and panel limits by code.

IDK, with the sub-panel full and those major loads already on it, it doesn't sound too good. I hope it's bigger than 100A.

Dryer 30 HVAC 30 Stove 40 or Ovens + Cooktop 60....

Yes, that's what you do. Or as Ed suggested, if it's a panel where half size breakers are available, you could free up space and not need the additional sub-panel.

IDK of any code reqt that say so. I think it depends on what the subpanel is being used for. If it's in a basement and and romex is going to run into it, then they use a backer board which gives you a place to staple the cables to as the enter the panel. But I've seen other sub-panels outside for pools and such that are just mounted directly to the house siding and where the wires enter and exit via conduit. That' what you'd have, with the UF cable going through conduit until it gets underground or if you use conduit and individual wires. With brick exterior, I'd probably use a backer board, just to keep it off the brick which can be damp.

If so, does the backer board need to be

Sounds like BS to me. I've seen a lot of them, never saw one painted black yet. It's not part of the NEC, that's for sure.

but I haven't checked locally. Lastly, what about a separate

It has to be grounded from the main panel. The ground and neutral also remain separate at the sup-panel.

It will be more so if there isn't enough capacity in that sub-panel.

On Wed, 20 Nov 2019 01:35:30 -0600, Jim Joyce snipped-for-privacy@none.invalid wrote:

There are a few things here you may have heard about that are wrong.

First the 3% is just a recommendation now a real rule and that would be based on you actually using all of that 20a at one time. 16a is a more realistic max design load (80% of your 20a). At 16a your #10 will drop 4.64v or 3.8%. Bear in mind that is a max continuous load for a

20 a circuit. If you want to use the "dwelling" exception to the 18" deep for conduit and 24" deep for UF rule, the GFCI protection needs to be at the house end of the circuit. If you are burying this 18" or 24" anyway that might not be important. You can get THHN/THWN conductors in 500' spools at home depot or they will sell it to you by the foot. The same "by the foot" is true of UF. If you would never use the left over, that premium they charge by the foot will come out cheaper. Just be sure you buy enough so you don't come up short. If you up size the current carrying conductors, you also need to up size the ground so it will end up the same size on a 20a circuit. (not #12). Code wise, you would be in violation with most UF cable since the ground for a #8 is typically #10 unless you specifically get the style with an 8ga ground. That will not be at Home Depot. For that reason alone, #10 would be a better choice. The reality is you would have a hard time finding a piece of cord and plug connected equipment that pulls more than 1440 watts. (12 amps). You have to seriously ask, "what are you really going to be doing out there"? If this is just a shed with a light, a receptacle for yard equipment and maybe a 1440w heater now and then. I bet #12 would be OK and #10 should be perfect. If you go much beyond that, like a sub panel, you will be driving ground rods, installing disconnects etc and this gets a tad more complicated. The simple answer is #10/2 for the underground. GFCI at the house so you can bury 12". They may want a local disconnect depending on your AHJ but it can just be a 20a rated snap switch and I would do the rest of the distribution in the shed with #12. If you really think you might change your mind and want a shop or something out there use conduit but if this is one and done, UF is fine. Personally I like wire in pipe but I also change my mind about things. If you do decide #8 is for you, it will be wire in pipe anyway unless you go to a real electrical supply and get 8/8/8 UF. Legally you can run 3 # 8s in a 1/2 inch but I would never try to actually pull that 120'. 3/4 or even 1' is a better choice and buy a bottle of lube. If I have a long run like that I squirt a little in the pipe every couple of sticks as I am putting it together, particularly in elbows. The pull goes a lot easier.

You are going to find that if you are wiring devices with #10 you better have greatly oversized boxes or you will have a real hard time stuffing that wire back in there. The fill calc for #10 is 2 cu/in per conductor and 4 more cu/in for the device. That adds up fast and the minimum size you come up with still might be hard to use. You will also be using industrial grade 20a devices to find ones that will accept 10 ga wire. Most 15 and 20a devices are limited to 12 ga.

You can replace one of the single pole breakers with a tandem and get an extra circuit that way.

These days isn't that all in your cell phone? If you really think you need signaling out there you could drop another 3/4" conduit in the trench for about $40 but that is so 20th century. ;-)

You have a point about learning when dinner is ready, but you can't get beer from cell phone.

Since we're throwing ideas around and since beer was mentioned, I'm reminded that the local Habitat ReStore has about 30-40 used mini fridges in the store, priced at $20 each. Looks like they came from a hotel. It might be nice to grab a pair and bookend the workbench. The problem would be keeping them fully stocked with beer while not wasting any space on water.

I have plenty of room, so using a bigger box to get room to work wouldn't be a problem. I haven't bought any of that stuff yet.

I just now checked the Leviton site and it seemed like nearly every switch can accommodate 10ga wire "back wired", but only 12ga if it's "side wired". I hope "back wired" doesn't refer to that push-in method but rather something more substantial. I may have to hold one in my hand to see what back wired is all about.

I'm sure it does.

They stopped saying "back-stabbed" because it encouraged violence.

They haven't come up with a 3rd method.

**Just kidding.

Load calcs don't usually work that way. If he has resistance heat you can rack up some numbers pretty fast but the FLA on AC compressors are nowhere near the breaker you need to support them. Ranges get calculated at 8 KVA (33a). Dryers typically have a name plate rating around 5500-5600 VA (22-23a). You also can use a 75% demand factor if there are 4 or more in the calc. The 2020 is going to revisit the load calcs in Article 220 but it will mostly be in commercial. I haven't really seen all the changes tho.

What the code does say is if this is against a masonry wall, the enclosure needs to be spaced out 1/4" if it is not on a board. (The AHJ may consider any exterior masonry wall a damp location)

As you say, it makes supporting the cables or conduits a lot easier with some kind of board. On outdoor installations the (NEMA) 3R enclosures usually have raised points where the mounting is to get you that air space so plywood is not needed. I am not sure plywood will hold up that well outside anyway. Mounted vertically it would certainly have to have the edges sealed (paint or something) or it will be de laminating in a year or two. I have never seen a rule on color but I have seen some AHJs say they wanted flame retardant paint. I am not sure where they get that rule.

That is why he needs a beer fridge out there. What do you think he wants the power for in the first place?

Nobody ever complained that this box was too big ;-)

They mean the clamping plate that is under the screw on better devices. That is true on spec/commercial grade devices but your normal Home Depot <$1 special just has screw terminals and maybe the dreaded spring back stab hole.

Terminate the BigAssedWire in a junction box and tap it off to 12 or

14 for your devices.

You need to stop buying those 49 cent receptacles in the barrel at the end of the aisle. Spec grade and Commercial grade devices have been using a clamping plate design for years. You can use one or two wires under each terminal point. This is not the stabber with a spring contact. It is a plate that the screw pulls in tight. I bet these would even work with aluminum wire but nobody has been brave enough to try to get them listed that way. I imagine half of the inflated cost of CO/ALr devices is the lawyer tax.