How many pole mounted transformer banks can a typical pole handle for general utility?

[Cartoon1]

My local utility can support up to 1200A 208/120V 3 phase service from a pole mounted type transformers. Their biggest pole mounted transformers are 167KVA. How is this typically done? Lets assume i have maximum demand of 424KVA Based on the maximum demand for a 1200 3 phase 208/120 gear. Do they typically add 3 167KVA transformers on the same pole? or do they put them on separate poles? (assuming pad mounted transformer is not an option) Thank you,

 

[Joethemechanic]

National Wood Pole Standards

https://woodpoles.org/portals/2/documents/WoodPoleCode_Overview.pdf

 

[hillbilly1]

Usually with that large of a service, they usually put in two poles with a platform to set the transformers on between them. Don’t see that much anymore, most want to do padmounts now.

 

[winnie]

A facility that I work with has a 1600A 480V three phase service.

The utility provisioned 3 250kVA pole mount transformers on a single pole in front of the building.

It is possible that the transformers are smaller than 250kVA; I'm not going by their nameplate but by the '250' label at the bottom of the cans.

-Jon

 

[electrofelon]

I did an overhead 480 service a 5 years ago that they served with 3x167's. There is 13.2kv->4800 step down bank in Cooperstown that consists of 3x300's on a single pole. That pole is hating life. I dont think I have ever seen 3X500's on a single pole, but lots of those on two pole platforms around here. user @mbrooke had some good pics of overloaded poles, but he hasn't been around in a while, and i cant find the old thread.

 

[David Castor]

It also depends on the class of pole. But if your calculated NEC load is 424 kVA, it's likely that the utility will install something smaller than than 3 x 167 kVA due to the inherent conservatism of the NEC load calculations.