Generator...service or feeder?

[bwyllie]

Generator is being used as a back-up to a building normal power via a 4-pole switch, is the wiring between the generator and transfer switch a feeder or a service? Would the ground be sized by 250.66 or 250.122?

 

[iwire]

Re: Generator...service or feeder?

It is a feeder

Artcle 100

Feeder. All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.

 

[ryan_618]

Re: Generator...service or feeder?

I would call it a feeder circuit. I don't think you can call it service conductors, because of the definition of them"

Service Conductors. The conductors from the service point to the service disconnecting means.

With a generator there is no service point.

 

[iwire]

Re: Generator...service or feeder?

To slow Ryan.

[ July 13, 2004, 03:40 PM: Message edited by: iwire ]

 

[ryan_618]

Re: Generator...service or feeder?

Originally posted by iwire:
To slow Ryan.

 

[bwyllie]

Re: Generator...service or feeder?

thanks, I actually found the different definitons after posting this. One bit of confusing still is the ground conductor between the generator and transfer switch an equipment ground or grounding electrode conductor?

 

[Ed MacLaren]

Re: Generator...service or feeder?

is the ground conductor between the generator and transfer switch an equipment ground or grounding electrode conductor?

I call it an equipment bonding (grounding) conductor. Green in the sketch below.

Ed

 

[necbuff]

Re: Generator...service or feeder?

Be careful here. your scenerio depends on the transfer switch. is the neutral solid or switched. if it is SOLID it is NOT a seperatly derived system (SDS), if it is SWITCHED it IS a SDS. It will depend on your case how you ground this service.

 

[bwyllie]

Re: Generator...service or feeder?

The ATS is a 4-pole switch, the transformer and generator feed into the ATS and then the ATS feeds into the Main switchgear inside the building, where the neutral to ground bond occurs. Transformer, Gen and ATS are outside. I originally designed for a 400kcmil ground, but the contractor sats we can use a 4/0 based upon 250.66.

[ July 13, 2004, 06:43 PM: Message edited by: bwyllie ]

 

[necbuff]

Re: Generator...service or feeder?

The picture u have is a little different. It IS a SDS because the neutral is switched. I would say, my opinion, what u have is service conductors. is this a utility xfmr? being the service disc is on the bldg like u said, u could use the neutral to bond non current carrying parts. sounds like u have a switched neutral. if so u have to have a MBJ in the gen. if the neutral were solid u would remove the MBJ in the gen.

 

[necbuff]

Re: Generator...service or feeder?

I may not fully understand your situation. My main point is you have to know what kind of switch u are dealing with in order for u to know what to do. Hope I did'nt confuse you. I stay confused myself most of the time.