Conductor Service Sizing

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potter

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My utility is telling me 4 sets of (3) 500MCM USE are able to supply my 1200A switch gear. When I told him my terminals were rated for 75 degree and would need more than that. He told me I was wasting my money.

Am I wasting money? Or is my Utility inspector nuts.
 
potter said:
My utility is telling me 4 sets of (3) 500MCM USE are able to supply my 1200A switch gear. ..................Am I wasting money? Or is my Utility inspector nuts.
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They are not nuts, they just have different rules and goals than we do working under the NEC.

First off where are these conductors in relation to the service point?

If they are on the utility side of the service point than run what the utility tells you and be happy.

If the conductors are on the customer side of the service point you will need to run 3 sets of 600 Kcmil CU or four sets of 350 Kcmil CU
 
potter said:
My utility is telling me 4 sets of (3) 500MCM USE are able to supply my 1200A switch gear. When I told him my terminals were rated for 75 degree and would need more than that. He told me I was wasting my money.

Am I wasting money? Or is my Utility inspector nuts.
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Potter,

Why you think you need more?

The allowable ampacity of 500KCMIL is 380 at 75 degree. So 4 sets of 500KCMIL can allow 4x380=1520.

What is USE?
 
dahualin said:
So 4 sets of 500KCMIL can allow 4x380=1520.

What is USE?
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I thought he was asking about three sets not four.


USE - Underground Service Entrance cable (direct burial)

He must be using Aluminum and we are thinking copper
 
barbeer said:
Kinda related- I notice mostly AL conductors being used these days and I'm not sure I like it all that much.
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Have you checked the price of AL vs. CU lately?
 
yeah its ugly! I also found some very interesting previous posts on the subject of AL- huh! I never heard of any re-engineering or such, I just heard from old timers the dangers of using it. In our trade continuing ed is the key, I like this site for some of that.
 
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