Trying to get power to a shed. Picked up a square d 70amp lug load center. Ran the conduit today and wired every thing up inside. Went to wire the service wire and think i made a mistake on choosing the wire. 8/2 is was i bought thinking i could run just 120 out to it on a 40amp breaker. Well the load centers power lugs are seperate, meaning i will have to have 2 hot wires powering each pole. Can i use the 8/2 for this? I would have to use the ground wire as the neutral to feed back to the meter box, and add a ground bar to the sub pannel and do a earth ground. Ideal would be a 10/3 wire or 8/3 but would hate to have to pull all the wire in the conduit.
Main lug load center wiring
- Thread starter caleb90
- Start date
wyliesdiesels
Well-known member
yeah lotta things wrong here.
by 8/2 i assume you got NM-b. this is not permitted underground
you need 4 conductors total.
no you cannot use the bare ground as a neutral.
grounding electrodes do not take the place of an EGC in a feeder. you need both.
you will unfortunately need to pull the wire out and start over
what size conduit did you run? I would use individual THWN conductors.
refer to post #3 and #4 in the Electrical FAQ sticky for guidance on how to do this
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They say it's UF so that seems fine
Is there a correct way to run a 120v only sub panel?
mike93lx
ALLIANCE MEMBER
Yeah, 3 conductor, as the OP has. Just tie the two poles together in the subpanel and dont run any two pole breakers
mike93lx
ALLIANCE MEMBER
If you want 120v only, you are fine to keep it. Just need to feed from a single pole breaker and tie the two buss bars together in the sub.
If you want 240v or 2x40a 120v, you need to run 4 conductors
Did you put the whole run in conduit? The purpose of uf is to run it direct burial and only protect with conduit where subject to damage above ground. When running conduit end to end, Thwn or XHHW are the best wires to use
mike93lx
ALLIANCE MEMBER
I am not aware of any code issues with what I sharedI mean, I knew that, but I'm not an electrician.
Should have said code compliant.
Could also just light up one side of the subpanel
Well, if it was me and I wanted 120v only, I'd put that hot line to a blue wirenut along with 2 other pieces, 1 to each hot lug.
Neutral to neutral, bare ground to ground.
But, I would have planned ahead and done a 240v sub if I was doing all that work.
Lorydr
Well-known member
You mentioned coming off a 40A breaker, so I would run 8ga wire. 10ga is rated for 30A.
I was
Was going to use a double pole 30amp in the meter box.
alfredeneuman
Well-known member
No matter if it was inspected or not it ought to be correct.
wyliesdiesels
Well-known member
aww UF in conduit is no bueno. what size conduit did you run?
are you running anything 240v off this panel?
wyliesdiesels
Well-known member
why does that matter?
Hahaha! I wasn't implying OP should cut corners or do something wonky. 100% agree it needs to be correct. Partly it was idle curiosity and partly figured the responses may be more specific for working towards an inspection. Mostly idle curiosity....
BreeStephany
ALLIANCE MEMBER
It doesn't matter whether or not it is inspected or not, it should be done correctly and to code. Code exists to ensure that things are properly and safely installed and to ensure that there are not issues down the road due to the installation methods used.
Well its all done. Decided that i didnt need 240 out there. Only have one 15amp circuit for lights and two 20amp circuits with 4 outlets on each circuit. Popped the trip bar off the double pole breaker, used one side for my 120v hot. Used a jumper in the sub pannel to make both lugs hot. I used direct burrial wire in the pvc conduit as a percaution. I dont see why that would be agaisnt code
mike93lx
ALLIANCE MEMBER
It isn't against code. It's just a pain in the *** and gives no benefit over conduit and thwn wire.
Not sure what you mean by that....
But if you've backed through a breaker it needs a hold down kit.
dave*99
Well-known member
If I understand this correctly, you have an unused pole on the 30A breaker in the meter box. That is fine. The "trip bar" is actually a handle tie. And depending on the brand, some breakers have an internal common trip and some rely on the handle tie to perform that function.
Since you are only using 1 pole of the 2 pole breaker, all that common trip and handle tie function is irrelevant.
sparky 1971
Well-known member
That isn't a trip bar, it's a handle tie so that both sides are turned on and off together. The common trip is internal, if you trip a breaker, both sides are going to trip, but now each breaker will have to be reset individually. It's the same reason two single pole breakers with a handle tie don't make a two pole.
dave*99
Well-known member
You would have to trip one side not just turn it off to know if there is an internal common trip. Trip is different than switching off.
The handle tie you removed provides common switching.
wyliesdiesels
Well-known member
do you have a main disconnect in the shed subpanel? did you isolate the neutral bus from the enclosure? install 2 ground rods?