400amp EGC

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Hey guys, so I'm thinking I might have goofed up on a wire pull, but maybe not, I'll explain.... I've got a 400 1ph breaker on a service, it feeds underground, across a yard via 2 3" pvc conduits, to a very large pole shed. Where it enters the building, I'm feeding 2 - 200amp panels. The conduits were installed just before it froze last year, we got one set pulled in and left the other until it got warmer. I pulled in AL 250MCM with a AL 4 ground. Then as I'm gearing up last night to get the next pull ready I said crap! I didn't size that ground for the 400, just the 200!

So looking in the code I know 250.122(F)(1)(B) says if conductors are installed in mutliple raceways and are connected in parallel the EGC needs to be sized in according to the overcurrent protective device. So now I'm thinking well guess who's pulling that #4 out and hopefully a #1 right behind it. But then I'm thinking well hold up, I am I technically connected in parallel? Yeah, I am at the breaker, but not at the end of the line with my 2 main breaker panels. So, I'm wondering maybe I'd be ok to leave the #4, maybe pull the next line in with a #1 and then maybe jumper between panels?

Kinda would not like to pull that out, it's kind of a long pull, plenty of pipe, just hate to do it. Thought i'd check with you guys before I bother my AHJ. Thanks.
 
Each parallel raceway requires an EGC sized according to the OCPD ahead of the feeder. As you've stated that's #1 Al in each conduit. I would try pulling out the just #4 and pulling a #1.
 
You have 2 200A feeder taps, not 200A conductors in parallel to make a 400A conductors.

But feeder taps are need an EGC sized per the supply OCPD, so you are still stuck with 400A EGCs.

If you can change to two 200A breakers at the supply side, then you are fine with 200A EGCs.

But watch out for 225.30 compliance, depending upon the code year the installation is under.

-Jon
 
winnie said:
You have 2 200A feeder taps, not 200A conductors in parallel to make a 400A conductors.

But feeder taps are need an EGC sized per the supply OCPD, so you are still stuck with 400A EGCs.
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Good point, since the conductors are not connected at both ends they are not parallel conductors.
 
User Name said:
Hey guys, so I'm thinking I might have goofed up on a wire pull, but maybe not, I'll explain.... I've got a 400 1ph breaker on a service, it feeds underground, across a yard via 2 3" pvc conduits, to a very large pole shed. Where it enters the building, I'm feeding 2 - 200amp panels. The conduits were installed just before it froze last year, we got one set pulled in and left the other until it got warmer. I pulled in AL 250MCM with a AL 4 ground. Then as I'm gearing up last night to get the next pull ready I said crap! I didn't size that ground for the 400, just the 200!

So looking in the code I know 250.122(F)(1)(B) says if conductors are installed in mutliple raceways and are connected in parallel the EGC needs to be sized in according to the overcurrent protective device. So now I'm thinking well guess who's pulling that #4 out and hopefully a #1 right behind it. But then I'm thinking well hold up, I am I technically connected in parallel? Yeah, I am at the breaker, but not at the end of the line with my 2 main breaker panels. So, I'm wondering maybe I'd be ok to leave the #4, maybe pull the next line in with a #1 and then maybe jumper between panels?

Kinda would not like to pull that out, it's kind of a long pull, plenty of pipe, just hate to do it. Thought i'd check with you guys before I bother my AHJ. Thanks.
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You are not connected in parallel if the load end connects to two different panels. Parallel or not, you still need a 3 AWG copper or a 1 AWG aluminum in each raceway.

Also those are tap conductors and you must comply with the requirements of 240.21(B)(5).
Is the 400 amp breaker on the exterior of the first building?
 
don_resqcapt19 said:
Also those are tap conductors and you must comply with the requirements of 240.21(B)(5).
Is the 400 amp breaker on the exterior of the first building?
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The 400 is in a small shed that is basically just for the property's main service. So using 240.21(B)(5)(4)(b) it's in a readily accessible location, inside, nearest point of entrance.
 
winnie said:
You have 2 200A feeder taps, not 200A conductors in parallel to make a 400A conductors.

But feeder taps are need an EGC sized per the supply OCPD, so you are still stuck with 400A EGCs.

If you can change to two 200A breakers at the supply side, then you are fine with 200A EGCs.

But watch out for 225.30 compliance, depending upon the code year the installation is under.

-Jon
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Thanks for the clarification, I think the plan is to pull the #4 out with a #1 hooked on, lube it up and hope it doesn't give me much trouble.
 
letgomywago said:
It's not plexed together right?
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It is not plexed, it just depends how twisted up it maybe got with the rest, just 1ph so it's only got 3 other wires vs 4 at least. 3" pipe I thought was overkill at first, kind of glad the owner actually talked me into it.

Suppose for some reason it won't pull out, and I'm not sure I want to attempt to pull it all out, is it against code to run two separate feeders to that building? Like swap out the 400 for 2 - 200's? I'd kind of think you'd want 1 disconnecting means to that building but maybe you can have more? Or maybe I can keep the 400 inside, add 2 200 feed-thru panels outside?
 
The general rule is that you are only permitted to have 1 feeder supplying a building. But in 2020 code was changed to add an exception that addresses your situation.

You can have up to six feeders originating from a single panelboard (so two 200A breakers in 1 panel), each supplying a single single disconnecting means (panels with main breakers), grouped in the building being supplied (so the two panels with main breakers have to be close to each other).

See 225.30.

-Jon
 
Thanks Jon I'll look that up, hopefully I won't need it but it's good to have back up plans.
 
Actually, that might be the way to go about it...I haven't opened my 400a breaker box yet...might be able to just return it for 200s...
 
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