Pole barn electric questions

[HunterDan]

So I'm to the point of planning electric in my 40x48 pole barn.

I'm planning on 2 outlets at every post, each on a different circuit, Lights, and a few outside lights and outlets. The panel is on the back wall in the corner.

I have 3 main questions.

#1
For the 2 outlets at each post, can I use 12-2-2 and run only one wire, but still be able to have 2 different circuits?

#2
For the front wall outlets, the run will be 48 feet up the Side wall, then have outlets start and run for 40' across the front wall. Is 12-2 gonna be sufficient for this as well?

#3
For the cieling lights, everything is open now, but I do plan on insulation, vapor barrier, and white metal. For you that have been there, what's the easiest way to go about wiring the lights? Put boxes and outlets or just leave the wire hang out of the cieling? I think I'm set on t5 Ho's, but haven't come up with a lay out, done any of that math (that'll be a whole other thread). I do want 3 switches so I can control either side and the middle.

 

[rburke65]

The 12-2-2 is a little expensive I hear but labor saving. You can use it and run 2 circuits with the seperate neutrals. And I think you will be ok on you question #2 and #3 as well. Did I say "I think"?....,

 

[racintj]

I did near the same as you on a 33x60 shop. Ran quads at each post, with left outlet on separate circuit as the right. You can share the neutral, but they have to be on the correct breakers in the panel. I'm not an electrician so I can't think of the right terminology at this moment.

12 ga wire will be fine. I pulled 12 ga through conduit. Shared neutral for each quad, and ran one shared ground that grounded to each box and outlet. Ran #6 copper wire from box to 2 x 5/8" x 8' copper rods driven in the ground more than 6' apart.

I used stranded wire.

 

[theoldwizard1]

I am planning on 2 outlets at every post, each on a different circuit, Lights, and a few outside lights and outlets. The panel is on the back wall in the corner.

I have 3 main questions.

#1
For the 2 outlets at each post, can I use 12-2-2 and run only one wire, but still be able to have 2 different circuits?

That is a "multi-wire branch circuit". Use 12/3. Black to one outlet, red to the other. They share a neutral and the breakers need to be of opposite "poles'.

 

[matt_i]

1) I feel like this isn't a good idea as it sets up a troubleshooting conundrum for you or someone else down the road. Better to keep it simple and reliable and put more wire under the staples. Copper is currently a good value. The other reason I don't like it, I have seen and troubleshot a shared neutral situation with 7 conductors in a tray cable, where it induced a 48vac voltage in a circuit which was powered off. That's an oddity to stay away from.

2) if you are using a GFI breaker for inspected work, I believe you will be limited to 10 outlets per GFI and thus per circuit.

3) Personally I like the largest round box in the ceiling, it can be anything from a duplex outlet to a direct wire thru a coverplate, to an inverted Edison-base fixture. If you want to upgrade a specific location to a 4-bulb T5HO for critical work, its right there without need to undo hard-wiring. However, for inspected work, I believe you will be required to have a GFI outlet controlling other outlets.

 

[HunterDan]

The old wizard, when you say "opposite poles", do you mean opposite hot legs in the panel?

I am not required to have any inspections (although o do want to keep things code compliant), except for having a gfci on my door opener outlets. But yes, outlet runs will start with. Gfi.

So for boxes, am I good to go with all plastic new work boxes?

 

[rburke65]

If you have the correct cubic inch volume per number of wires.

 

[theoldwizard1]

The old wizard, when you say "opposite poles", do you mean opposite hot legs in the panel?

Yes. Typically they are mounted next to each other, but that is not a requirement. You do NOT want the handles of the breakers linked together.

12/3 is black, white and red so the hots are easy to see.

 

[Norcal]

Yes. Typically they are mounted next to each other, but that is not a requirement. You do NOT want the handles of the breakers linked together.

12/3 is black, white and red so the hots are easy to see.

Depending on the code edition, it's required to use handle ties for multi-wire circuits and on opposite legs as having them on the same leg opens up the possibility of burning up the neutral.

See 210.4(B), handle tie required in the 2008, 2011, 2014 NEC editions.

 

[HunterDan]

So in my panel, I would have the 12-3, 20 amp single breaker/red wire to one hot leg, black wire/single 20 amp breaker to the other hot leg, correct?

 

[theoldwizard1]

Depending on the code edition, it's required to use handle ties for multi-wire circuits and on opposite legs as having them on the same leg opens up the possibility of burning up the neutral.

See 210.4(B), handle tie required in the 2008, 2011, 2014 NEC editions.

IANALE. Learn something new every day !

 

[theoldwizard1]

So in my panel, I would have the 12-3, 20 amp single breaker/red wire to one hot leg, black wire/single 20 amp breaker to the other hot leg, correct?

Based on what Norcal just posted, get a 240V 20A breaker. Wire the black to one screw and the red to the other. That's it !

 

[pattenp]

On a MWBC the difference of using two single pole breakers with handle ties over a common trip double pole is if one circuit trips due to a fault you won't lose power on the other circuit. Using a double pole common trip will take out both circuits if there is a fault on either one. If the MWBC is powering a line-to-line load then DP common trip breaker must be used.

 

[Norcal]

On a MWBC the difference of using two single pole breakers with handle ties over a common trip double pole is if one circuit trips due to a fault you won't lose power on the other circuit. Using a double pole common trip will take out both circuits if there is a fault on either one. If the MWBC is powering a line-to-line load then DP common trip breaker must be used.

If the load is line to line then it must comply w/ 210.4(C), there are a couple of exceptions to that requirement. 210.4(D) also has conductor grouping requirements for multiwire circuits in a panelboard.

 

[pattenp]

If the load is line to line then it must comply w/ 410.4(C), there are a couple of exceptions to that requirement. 410.4(D) also has conductor grouping requirements for multiwire circuits in a panelboard.

I believe you meant 210.4

 

[Norcal]

I believe you meant 210.4

You are correct. I will edit the post.