bonding of generators

[kerinsbr]

Hooking up Temp Generators. If the generator is internally bonded to the nuetral and the source is also bonded to the neutral,what will happen if we have a short or a ground occur? What would be the proper way of safely protecting the generator and source?

 

[taylorp]

Re: bonding of generators

Kerinsbr:

I am guessing that you are using a generator to temporarily feed an existing building which already has a properly bonded and grounded "neutral." Is this right? How you ground and bond your generator "neutral" would depend on whether it IS or IS NOT a Separately Derived System (see Article 100 of the NEC.)

If your system IS NOT a Separately Derived System, then follow 250.20. If your system IS a Separately Derived System then follow 250.30.

The "neutral" is usually only grounded at one point in the "system" because of possible parallel-neutral pathways. (See 250.142)

Your generator may have access where you can bond and un-bond your "neutral" depending on whether the generator IS or IS NOT a separately derived system.

In this case:

It all depends on what the definition of Is Is?.

 

[taylorp]

Re: bonding of generators

Kerinsbr:

I forgot to mention 250.24 for Grounding AC systems. It also discusses grounding "neutral"
at one point in the system (unless permitted
otherwise.)

You might want to study Articles 215, 230, 250,
445, 700, 701, 702, and 705 of the National
Electrical Code.

P.S. As a generator tech., do you install generators? Or do you repair them when they get
back to the shop?