New service

[AIR COOLED]

Hello guys, I am having a house built with 400 amp service. The local utility is trenching 3 conductor AL 500 MCM feeder to my meter. Is that size big enough? I changed my service on the plans prior to construction from 350amp to 400amp.

I feel the utility was not notified of the change and the builders electrician did not catch this. No wires have been run but I just signed off on the change order to pay for the 160 feet of trenching. I decided to double check the ampacity of 500mcm since it was on the quote.

From what I calculated using the 83% rule, 350 amp service (290amp @75 c) should have 500mcm feeders and 400 amp (330 amp @ 75 c) should have 600mcm. feeders. I am in Florida and it will run down the pole and run underground 160ft until it pops up into the meter.

I would appreciate any help.

Thanks guys, first time poster!!!

 

[kwired]

Hello guys, I am having a house built with 400 amp service. The local utility is trenching 3 conductor AL 500 MCM feeder to my meter. Is that size big enough? I changed my service on the plans prior to construction from 350amp to 400amp.

I feel the utility was not notified of the change and the builders electrician did not catch this. No wires have been run but I just signed off on the change order to pay for the 160 feet of trenching. I decided to double check the ampacity of 500mcm since it was on the quote.

From what I calculated using the 83% rule, 350 amp service (290amp @75 c) should have 500mcm feeders and 400 amp (330 amp @ 75 c) should have 600mcm. feeders. I am in Florida and it will run down the pole and run underground 160ft until it pops up into the meter.

I would appreciate any help.

Thanks guys, first time poster!!!

First welcome to forum.

Second you mostly started a new topic here and should have opened it in a new thread.

In answer to your question - POCO does not need to comply with NEC and can run whatever they want, I didn't check your calculations but you would likely need to comply with NEC if you were running these conductors.

There are POCO's around here that run 350KCMIL aluminum to 400 amp services without even knowing actual load details, but they must know what they are doing as you seldom see troubles with them either.

 

[charlie b]

I started a new thread so that your question can be addressed separately.

 

[electrofelon]

Hello guys, I am having a house built with 400 amp service. The local utility is trenching 3 conductor AL 500 MCM feeder to my meter. Is that size big enough? I changed my service on the plans prior to construction from 350amp to 400amp.

I feel the utility was not notified of the change and the builders electrician did not catch this. No wires have been run but I just signed off on the change order to pay for the 160 feet of trenching. I decided to double check the ampacity of 500mcm since it was on the quote.

From what I calculated using the 83% rule, 350 amp service (290amp @75 c) should have 500mcm feeders and 400 amp (330 amp @ 75 c) should have 600mcm. feeders. I am in Florida and it will run down the pole and run underground 160ft until it pops up into the meter.

I would appreciate any help.

Thanks guys, first time poster!!!

As Kwired sad these are probably not NEC conductors. Even if they were, since you will most likely be feeding two service disconnecting means, they can be sized to the load calculation not the sum of the service disconnects.