Standby Generator

[tomgilmartin]

I have an application for a standby generator which I would like to use to feed 2 separate buildings. The question is, does the Service Entrance code 230.3 apply to this generator? Specifically, can I run the output of the generator through building 1 to feed building 2?

 

[nvcape]

Re: Standby Generator

Suggest you review the definition of "service" to start; it isn't a service. If possible, avoid this, especially if the buildings have separate services and 480V with GFI. If required, suggest 4 pole transfer switches. This isn't for someone not familiar with all the issues.

 

[bob]

Re: Standby Generator

Do the buildings have seperate services from the utility?

 

[tomgilmartin]

Re: Standby Generator

The current plan is for the buildings to have separate services. Building 1 has 3 25kva transformers on a pole, building 2 has 3 150kva transformers on a separate pole. Both are fed from the same 4160 overhead line.

 

[bwilson]

Re: Standby Generator

Tom. Take a look at 225.31 thru 225.40. This will cover your instalation.

 

[nvcape]

Re: Standby Generator

If the buildings have different addresses, and could be sold separately, check the legal issues. We need to have easements and agreements written into the deeds.

 

[bob]

Re: Standby Generator

Tom
What are you going to do when building 1 is still energized and you loose building 2, transfer building 1 so you can pick up building 2? You will still need a transfer switch at 2 to seperate from the utility. Why not install 2 transfer switches and two circuits from the generator and operate seperately?

[ October 03, 2003, 03:31 PM: Message edited by: bob ]

 

[tomgilmartin]

Re: Standby Generator

Originally posted by bob:
Tom
What are you going to do when building 1 is still energized and you loose building 2, transfer building 1 so you can pick up building 2? You will still need a transfer switch at 2 to seperate from the utility. Why not install 2 transfer switches and two circuits from the generator and operate seperately?

Bob,
Separate ATSs and circuits were my intention from the start, the question was whether I can run the feed for building 2 THROUGH building 1 (there is existing cabling), or whether I need to run the conduit from the generator OUTSIDE building 1 and then to building 2. Maybe that wasn't clear in the original post.

 

[nvcape]

Re: Standby Generator

The NEC handbook, article 250.20 starts to answer you question. When a 4 pole transfer switch is used, the generator is listed as a "separately derived system." The definitions in 100 say a service is the serving utility, not a generator. Article 225.30 lists generator feeders. Article 225.37, for identification, mentions feeders passing through a building. This probably goes back to service conductors being protected by the Utility and not NEC requirements.