What Size Wire For 400 Amp Service

• #2

Are y'all needing all 400 amps?

• #iii

millspgh said:

I need to give a price on a 400 amp, 3 phase four wire service, and I don't want to become burned by the derating upshot. I was planning on running four 500mcms in a 4" pvc pipage, the pipe will be about 100' long above a drop ceiling in a retail surface area. I know by having four current carrying conductors I need to derate, but I am non certain how to go near this, any assist is appreciated.

It seems way too far for service conductors considered inside the building envelope. If you end up with feeders, will y'all need to include an equipment grounding conductor in the conduit also? :-?

• #half-dozen

310.16...

310.sixteen...

millspgh said:

I know I will demand an equipment ground also. I am sure th store volition not need all 400 amps, just the console will be a 400 amp main breaker panel

Right me if I'grand wrong only according to Table 310.sixteen -- 500 CU is only rated at 380 amps at lxx deg.

roger

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• #7

millspgh, I think you're confusing Feeders and Services. You should read 310.15(B) for whether the neutral will need to be counted as a Current Carrying Conductor.

Roger

Last edited: May seven, 2007

• #8

Mills, are you lot designing this or bidding from plans?

• #9

1793 said:

Right me if I'chiliad wrong merely co-ordinate to Table 310.16 -- 500 CU is only rated at 380 amps at seventy deg.

Would 240.4(B) allow him the next standard rating?

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New Jersey

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Journeyman Electrician

• #11

The 500's tin can be used if your connected load is 380 amps or less and protected at 400 amps. The neutral would have to have more than 50% of it's load every bit non-linear for information technology to count every bit a CCC.

• #thirteen

dollar shop??

dollar store??

probally manner off the topic. but a 400A service for a dollar store seems like alot to me..

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New Jersey

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Journeyman Electrician

• #xiv

millspgh said:

My load will be much less than 380 amps, how do I bank check that neutral usage you only mentioned? I do capeesh everybodys input here, thank you.

Yous would have to figure out what your harmonics loads are and how large they are. IMO in a shop they wouldn't be a factor.

• #15

Mike01 said:

probally manner off the topic. merely a 400A service for a dollar store seems like alot to me..

Perchance, for this tenant. But for the next it may not exist plenty.

• #16

Originally Posted by millspgh
I know I will need an equipment ground also. I am sure th store will non need all 400 amps, only the panel will be a 400 amp main breaker panel

1793 said:

Correct me if I'g wrong but co-ordinate to Table 310.sixteen -- 500 CU is only rated at 380 amps at 70 deg.

I posted without reading carefully, I missed the "not" in the original post. Pitiful

What Size Wire For 400 Amp Service,

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