iwire said:
No, we are not fooled by that thought. However, we use a set of 500 kcmil Al. for each multiple of 400 amperes due to the fact that services are normally oversized in the smaller buildings and their load profiles are such that we can get away with smaller laterals. For the underground services, we provide service laterals for 1200 ampere services and below. For large overhead services, the service drop is sized to carry the full output of the transformer bank. The service drop is parallel 1000 kcmil Cu. for a 3000 ampere service. Skin effect is not a factor :wink: but taking up space on the building wall is a factor. We will not permit a service larger than 3000 amperes.Pierre C Belarge said:
Is this all states? I just recently had a conversation with a guy that installed a 4000I system,and he said POCO pulled in AL that was too small. I was thinking to myself,Because POCO did the math and he couldn't utilize a 4000I service.Very interresting.charlie said:No, we are not fooled by that thought. However, we use a set of 500 kcmil Al. for each multiple of 400 amperes due to the fact that services are normally oversized in the smaller buildings and their load profiles are such that we can get away with smaller laterals. For the underground services, we provide service laterals for 1200 ampere services and below. For large overhead services, the service drop is sized to carry the full output of the transformer bank. The service drop is parallel 1000 kcmil Cu. for a 3000 ampere service. Skin effect is not a factor :wink: but taking up space on the building wall is a factor. We will not permit a service larger than 3000 amperes.
All electric utilities do things a little differently and we share our procedures with each other. Some things one electric utility does may be picked up by another electric utility. However, you can't just assume we are all the same. In general, electric utilities will not supply customers with full size conductors or use "large enough transformers for a particular installation. The big difference is that we are always there and will beef up service drops or laterals, replace transformers, replace secondaries, and rework any other equipment at any time in the future if it is undersized or fails. This work will be done at no charge to the customer unless the customer has changed the parameters of his load.Karl H said:
Just an added note: If the suppliers in your area are overcharging for 600's, you could use 9-sets of 750's (9 x 475 = 4275). This also cuts down on # of conduits. I've found that a lot of suppliers these days are trying to consider 600's to be a 'premium' or special order size. I don't see why, though, because I see many jobs out there using 600's. Has anyone else seen this to be the case in their area?iwire said:
chaterpilar said:
