Service entrance ampacity commercial

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wrestless

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OK here goes just met with an electrical inspector here and said why did you run 3/O copper for your service entrance conductors 200 amp service and the building is commercial. Ready ? He says well if you look at Art : 310.16 4/0 aluminum has a rating of 175 amps therefore if its under 800 amps you can go to the next size breaker which is 200. What ya all
think about that ?
 
wrestless said:
OK here goes just met with an electrical inspector here and said why did you run 3/O copper for your service entrance conductors 200 amp service and the building is commercial. Ready ? He says well if you look at Art : 310.16 4/0 aluminum has a rating of 175 amps therefore if its under 800 amps you can go to the next size breaker which is 200. What ya all
think about that ?
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I think he is right as long as the calculated load is not greater than 180. BTW 4/0 alumin. is 180 amps.
 
wrestless said:
Art : 310.16 4/0 aluminum has a rating of 175 amps therefore if its under 800 amps you can go to the next size breaker which is 200. What ya all
think about that ?
Click to expand...

If it were 175 amps then you could not use a 200 amp OCPD.
 
infinity said:
If it were 175 amps then you could not use a 200 amp OCPD.
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Sorry my bad I must have had a brain f..t 180 amps. So how is it that I have got knocked down before on commercial services for installing 4/0 aluminum by the same agency and had to change it 2 years ago to 3/0 copper . Man I am definetely loosing it guess I better do some continuing ed classes like soon. Thanks guys
 
wrestless said:
Sorry my bad I must have had a brain f..t 180 amps. So how is it that I have got knocked down before on commercial services for installing 4/0 aluminum by the same agency and had to change it 2 years ago to 3/0 copper . Man I am definetely loosing it guess I better do some continuing ed classes like soon. Thanks guys
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Few possibilities:
Same POCO ? Locally we deal with several POCOs, some of which will not accept an aluminum riser.
Also, if you install 4/0 AL on a 200 amp commercial service most of the local inspectors will require a documented load calculation. If you can not provide that, the 4/0 won't pass here.
 
wrestless said:
Sorry my bad I must have had a brain f..t 180 amps. So how is it that I have got knocked down before on commercial services for installing 4/0 aluminum by the same agency and had to change it 2 years ago to 3/0 copper . Man I am definetely loosing it guess I better do some continuing ed classes like soon. Thanks guys
Click to expand...
I am doing a small commercial job now and the engineer has a calculated load of 115 amps. So 4/0 alum. is fine.
 
augie47 said:
Few possibilities:
Same POCO ? Locally we deal with several POCOs, some of which will not accept an aluminum riser.
Also, if you install 4/0 AL on a 200 amp commercial service most of the local inspectors will require a documented load calculation. If you can not provide that, the 4/0 won't pass here.
Click to expand...

Also if I run 250 kcmil al at 205 does that mean Im can go 225 main after all next size breaker from 200 is 225 . Just a question trying to feed my little brain LOL Again had the same problem in NY made me go to 4/0 copper for 225
 
It does.... same basics apply... calculated load must not exceed 205, etc.
 
You need to remember that if the customer ever needs the full 200 amps they technically will not have it without repulling the wire. If, in my situation, the calculated load was 160 or so and I thought there was a chance for expansion then I would not use 4/0 alum.
 
Dennis Alwon said:
You need to remember that if the customer ever needs the full 200 amps they technically will not have it without repulling the wire. If, in my situation, the calculated load was 160 or so and I thought there was a chance for expansion then I would not use 4/0 alum.
Click to expand...

Thanks again guys I guess for some reason the increase in breaker was not relative to services. I have to hit the book more the older I get the more I forget.
 
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