Pole barn shop wiring

[scotts90ranger]

Ok, Some might remember my shop build from a while ago since it's been a 2 year project so far, but it's close...

I'm finally close, I have a new power service going to the shop that has a new 320A service with meter at the shop with two 200A mains feeding the house and shop, and a new 200A panel in the shop. The last thing before the final inspection is to get a few circuits wired in "correctly"...

I try to do things right but I am NOT going to buy a full assortment of $55+ GFI breakers to go to code when normal breakers are $6-20... I just bought a 20A GFI single pole breaker to start with the light circuit, I'll probably get another tomorrow to add a couple outlets, I just wanted to know it was the right breaker before I spent the $$.

My main question is on a secondary structure what the requirements are for wiring without enclosed walls... I would prefer to just wire with PEX, but it will be exposed. I know it shouldn't be under 18" high.

If PEX isn't going to pass inspection I do have a roll of MC, it looks like it's harder to deal with, not to mention it's more expensive (I think I only got it for like $80?, it's $200 now), if I gotta I gotta, boxes are more expensive since you have to use metal...

When I was in Lowes a couple hours ago I got stuff prepared to run a few circuits with MC... I don't think my county is too strict.

 

[Uncle Gump]

I can't help you with wiring to code on your project...

But just commenting on the price of supplies. Outrageous. I'm going to try and finish what I want to do with some leftovers I've been hanging onto from my basement. I will only buy exactly what I need to finish what I have planned.

 

[ericbphoto]

Pex is for plumbing. Not suitable for electrical use. You can use electrical grade PVC (gray color). Basically, anything below the ceiling must be protected from mechanical damage. So PVC conduit, EMT conduit and MC cable are all good. I was going to use MC cable on mine since I had a bunch left over from my contracting days plus a Craigslist purchase. Mybsecond choice would be EMT. But I'm used to running EMT. PVC is easy. I haven't priced any of those in the past 3 years. So I don't know cost comparisons.

 

[Roert42]

MC would be the easiest/ quickest. EMT might be cheaper, probably the best for a shop tops I’ve it’s easy to add on. I don’t like PVC, PITA.

If you cover the walls after you wire it, you should be able to use regular romex.

You may not need GFCI for all your circuits, depending on the layout and intended use of the build.

Should go to your local library, borrow a current NEC, and look up the requirements for exactly what you are trying to do. Some areas the local code goes above and beyond the nec, but a good place to start.

 

[ericbphoto]

MC would be the easiest/ quickest. EMT might be cheaper, probably the best for a shop tops I’ve it’s easy to add on. I don’t like PVC, PITA.

If you cover the walls after you wire it, you should be able to use regular romex.

You may not need GFCI for all your circuits, depending on the layout and intended use of the build.

Should go to your local library, borrow a current NEC, and look up the requirements for exactly what you are trying to do. Some areas the local code goes above and beyond the nec, but a good place to start.

It'll take a beginner forever to sort through the NEC and figure out everything that applies to the project.

 

[scotts90ranger]

I don't know why I posted PEX, I know that's plumbing... I meant Romex...

 

[Roert42]

It'll take a beginner forever to sort through the NEC and figure out everything that applies to the project.

Absolutely.

but if he end up needing to redo a bunch of work because it’s wrong, or does a bunch of work unnecessarily it will save him some time and money in the long run.

 

[ericbphoto]

Here's the basic rundown for a home shop like this.

15 amp circuits need 14 gauge wire
20 amp circuits need 12 gauge wire
30 amp circuits need 10 gauge wire.
40 amp circuits need 8 gauge wire.
Anything bigger, just ask and I'll look it up for you.

Anything below the ceiling where it could be easily damaged must be protected. Either run romex in the walls and then cover with sheet rock or plywood, OSB, etc. Or use MC cable (MC = metal clad), armored cable, or electrical rated conduit.

There are rules about how many wires can be in a conduit. If in doubt, ask. It gets complicated. Don't do more than 6 and you'll probably be ok. And if you have 6 wires in a conduit, even as small as 12 gauge wires, you should probably upsize to 3/4" conduit. Bigger wires or more wire = bigger conduit.

GFCI protection for receptacles- I haven't read up on that recently. Last time I looked, Anything close to a water source, like within 6ft of a sink, or in a bathroom, Anything in a garage and anything outside. Would be a good idea to ask your local inspector what he likes to see. You can use a GFCI breaker in the panel to protect the circuit. Or you can use a GFCI receptacle as the first one on the circuit and wire it so it protects all the others on that circuit.

Make sure metal boxes, fixtures and conduit are tied to ground.

That's 90% of what you need for lighting and receptacle circuits.

 

[RonD]

For AC wiring there is BX(armored) and Romex(insulated)

In some case Romex needs to be installed inside a conduit, for protection
BX does not as it's already protected
You need to look at cost between the two options as a cost per foot
Some times BX is cheaper, and easier to work with vs conduit/romex

With BX you should use metal outlet boxes, the main panel should be metal as well
Some equipment like furnaces require BX

You can mix BX and Romex, i.e. romex for lighting and BX at floor level outlets where wire damage may be more likely, lol

Wire size needs a higher AMP rating than the Breaker, or "the wire" becomes the breaker/fuse, lol
Same for outlets, 15amp outlet on a 20amp breaker.............switch to 15amp breaker or 20amp outlet

All electricity requires 2 wires, in DC circuits amps/current flow from one pole to the other, + to - or - to +, doesn't matter, what matters is that it flows in a full circle in one direction, from one pole all the way to the other pole

AC circuits have amp/current flow only at the device being powered, not pole to pole
AC alternates + and - on each of the two wires, this causes the amps/current to move back and forth inside the device, which generates the power needed by that device

Breakers just measure amp flow on one of the wires, well the heat of that amp flow really
GFI compares the amp flow between the 2 wires, if one wire draws more amps the breaker opens, they also open if amp draw is higher than rating, so they do both

You can use GFI outlets, say on outside outlets, or any "wet" areas, vs GFI breaker
AC power, wet concrete and human beings are not a good combination, lol

 

[dirtymike]

NEC

 

[Roert42]

In some case Romex needs to be installed inside a conduit, for protection

There is no good reason to put romex in conduit. Giant waste of money.

 

[ericbphoto]

There is no good reason to put romex in conduit. Giant waste of money.

Generally, you will run individual conductors of typ THHN wire in conduit. But, if all you have is a few short runs, it could be less expensive to just run romex in it instead of buying separate rolls of black, white and green wire. It works both ways. Down below the ceiling, the wire needs the mechanical protection of cladding or conduit.

 

[Roert42]

Generally, you will run individual conductors of typ THHN wire in conduit. But, if all you have is a few short runs, it could be less expensive to just run romex in it instead of buying separate rolls of black, white and green wire. It works both ways. Down below the ceiling, the wire needs the mechanical protection of cladding or conduit.

Main problem is the conduit size. For conduit fill you have to size the conduit using the cross section of the cable/ romex.

One piece of romex takes up a lot of room in your conduit, and probably would need a larger size of conduit compared to a few conductors. not to mention harder to pull.

If you are working with what you have laying around, best bet would to just strip the jacket off the romex. Plus, if you are using EMT you don't need to bother with the ground wire, if nothing else you are saving a few feet of coper wire to be used somewhere else.

 

[ericbphoto]

Yes, romex takes a lot more space. But, generally, in this situation, it will only be one piece, maybe 2. He'll find out quickly that it's a challenge to stick any more than that in there.

No. You do not skip the ground wire in EMT or intermediate conduit or ridged conduit. The ground is not counted for conduit fill because it is not a current carrying conductor in normal circumstances. But it must still be installed.

 

[RonD]

Looking at Homedepot.com prices

Romex 12/2 is $1.09/ft in 100ft length

BX 12/2 is $1.28/ft in 50ft length

EMT is $.90/ft for 1/2", 10' length is $9
3/4" EMT is $1.40/ft, $13.99 for 10'
PVC is about the same

I would agree if using EMT or PVC conduit then individual wires would be the only thing that would make sense, or CENTS, lol
But...............unless you are buying it in 500ft rolls 12ga solid wire is $.50ft, need 3 = $1.50ft
500ft rolls its $.25/ft so would be $.75 but then there is the conduit cost, so with 1/2" its $1.15/ft

Conduit is nice if you think you may want to add more circuits down the road, pull in more wires as needed, so you would want to use minimum 3/4" but 1" would be better