I have a shop with a 125 amp panel in it. I'll be running the wire to the panel box from a 200 amp load center mounted about 30' away. The feeder wire will need to be run underground either direct burial or in conduit. There is already 2" conduit run to the bottom of the shop panel. Best I can calculate it would be 1/0 aluminum or 1 awg copper. I checked Home Depot, I don't think the 1/0 will fit in the lugs for the 125 amp breaker. What wire would be recommended for this?
125 amp feeder wire
- Thread starter catldavis
- Start date
mike93lx
ALLIANCE MEMBER
do you need 125A? the feeder doesn't have to match the rating on the panel. you can do anything smaller, as long as it fits in the lugs. do you already have the 125a breaker?
1/0 aluminum should fit that breaker fine. what makes you think it wouldn't?
2 gauge aluminum will be good to 90A. 1/0 is right for 125A
you'll need two ground rods, and it will have to be a 4-wire feeder as well
This wire would be fine, if the conduit is continuous.
use a 4 gauge ground: https://www.wireandcableyourway.com/1-0-xhhw-2-aluminum-building-wire.html
if you need something that will be direct buried for part of the run, this would work: https://www.wireandcableyourway.com/2-0-2-0-1-4-aluminum-mobile-home-feeder-cable.html
the subpanel has a main breaker or other disconnect, correct? it can't be main lug
1/0 aluminum should fit that breaker fine. what makes you think it wouldn't?
2 gauge aluminum will be good to 90A. 1/0 is right for 125A
you'll need two ground rods, and it will have to be a 4-wire feeder as well
This wire would be fine, if the conduit is continuous.
use a 4 gauge ground: https://www.wireandcableyourway.com/1-0-xhhw-2-aluminum-building-wire.html
if you need something that will be direct buried for part of the run, this would work: https://www.wireandcableyourway.com/2-0-2-0-1-4-aluminum-mobile-home-feeder-cable.html
the subpanel has a main breaker or other disconnect, correct? it can't be main lug
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Yes, unfortunately, 125 amp is required.
Unless I'm missing something (which is entirely possible), the 125 amp breaker is the main in the subpanel.
4-wire feeder...Hmmmm, the breaker has two wires and then there's the ground, where does the fourth wire go? Maybe I should try to host a picture of the panel, that might help.
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Aceman
Well-known member
If you don't take a 4th wire, in this case a neutral, you will not be able to run any 120v loads.
I'd be more concerned with the fact that you need a 125 amp panel, fed from a 200 amp loadcenter. What else does the loadcenter feed?
I'd be more concerned with the fact that you need a 125 amp panel, fed from a 200 amp loadcenter. What else does the loadcenter feed?
Here's an image of the panel box. You can see where the previous owner just cut the wires to the 125 amp breaker on the top right of the breakers.
Your pic doesn't work, but I followed the link.
This is the sub panel? If so, that breaker is backed (and should have a retaining clip so it can't be removed) and acts as a disconnect only.
The wire is protected by the breaker in the main panel. What size is there?
In other words, if you have a 90A (or smaller) breaker in the main, you size the wirw for at least that and then feed the sub, and all is well. 90Ashould be plenty.
Here's an image of the panel box. You can see where the previous owner just cut the wires to the 125 amp breaker on the top right of the breakers.
That cb will handle up to 2/0.
Just because the sub-panel main is 125a, does not mean you have to provide a feeder with that rating. It could be lower like 90a.
If you want 125a, then you need 1/0, 1/0, 2, 4 AL in the pvc conduit and 125a cb in main panel.
4 wires = 1/0, 1/0 - hots, #2 - neutral, #4 - equipment grounding conductor.
For 90a feeder:
you need 2, 2, 4, 6 AL in the pvc conduit and 90a cb in main panel. (125a cb can remain in sub palnel.)
4 wires = 2, 2 - hots, #4 - neutral, #6 (green) - equipment grounding conductor.
Need 2 ground rods at garage and isolated neutral in sub-panel.
No link is found in the original post, but when replying to the post, the link shows up.
alfredeneuman
Well-known member
What's the white wire on the twin breaker (2nd from bottom left) doing?
It appears to be terminated on the breaker.
It appears to be terminated on the breaker.
pattenp
Well-known member
When you go to purchase wire just make sure you don't purchase URD because it does not carry a fire resistance rating and is not to enter the structure. Use either THWN or XHHW in conduit, if direct bury use RHH/RHW-2/USE-2 which is the same that Mobile Home Feeder is made up from.
2 gfci cb's
Looks like there may be a few in that corner where the white wires are terminated on twins...
Also I don't see any grounds?
OP, can you get some better pics, of this and the main panel?
Looks like there was some issues, probably flagged during a pre-sale inspection, and rather then fix the previous owe just cut the feed.
alfredeneuman
Well-known member
Now I see the buttons. I thought they were labelsmike93lx
ALLIANCE MEMBER
IMO, you need an electrician if you don't know where the 4th wire goes
I see. The loadcenter also runs three 20 amp circuits ans two 60 amp circuits.
Don't know why the link isn't working.
Yes, this is the subpanel. The main breaker is 200 amp.
How have you determined you need 125 amp?
pattenp
Well-known member
No link is found in the original post, but when replying to the post, the link shows up.
The link was posted as an image and GJ doesn't play well with third party photo hosting sites. Should have just posted the link as a link, not an image.
Such as : https://photos.app.goo.gl/K4j4Y6urwuGc22kH8
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Thank you for the reply. Is there a disadvantage to going with 125 amp (other than additional price)? Also, would you also recommend XHHW-2?
Thanks for the reply. Not necessarily, Just matching it to the 125 amp breaker.
no need , the breaker in the sub panel is merely a means of disconnect . the breaker feeding the sub panel from the main determines the wire size . you could put a 40 or 60 amp breaker in the main and run the appropriate sized wire to the sub and be compliant
Yes, can get better pictures but I'm visiting relatives.
Wasn't cut due to an inspection, the previous owner (who is an acquaintance) was going to replace the box with a larger one but was told everything in the building would need to be brought up to 2014 NEC (we're in Florida). Why he didn't just remove the wire from the lugs, I'm not sure.
I totally agree, I would never attempt to hook it up. Just trying to learn so I have an idea if what the electrician is telling me is correct or not.
wyliesdiesels
Well-known member
If you dont understand the reason for the 4-wire feed or where the 4th wire goes, then go checkout the electrical FAQ sticky thread.
There is info on there about 4-wire feeders.