Two stuctures from one service

[jim mccloy]

This is a commercial installation. If there is a main service that comes in at an existing building and is tapped ahead of the main to an EXISTING 150 amp disco (located outside of the first building) and then on to a new service (which is actually a sub-panel) at a structure under construction, that replaces an old structure, do the service conductors that feed the new building from the outside disconnect need to be 4-wire feeder in order to have separated neutral and ground?

I believe that phone service (underground) from the first building is planned to be run to the second at a future date.

[ June 14, 2003, 04:12 PM: Message edited by: jim mccloy ]

 

[pierre]

Re: Two stuctures from one service

Jim

If you meet the requirements of 2550.32, you will not be required to run the 4th conductor, provided this is a single phase setup.
But... since you know that a phone line will be connected between the two buildings, and most likely it will be bonded to the system, be prepared and install the EGC with your feeders.

just my opinion,

Pierre

 

[jim mccloy]

Re: Two stuctures from one service

Pierre

Thank you for responding...and that's what I wanted to hear.

Also, 250.32(B)(2) states that as long as ground fault protection is not installed to protect equipment on the common ac service the 3-wire system is ok. In my case there IS ground fault protection in the form of a circuit breaker in the main service.

I'm just trying to justify going to the customer and stating these code ref's in order to get him to let me provide a proper installation.

The old 3-wire setup is partly underground and about 100 feet in length. I doubt there going to want to spend the money upgrading to 4-wire feeder...but I have to think about what these people will be doing with this building in the future.