Utility/Generator

[David Rogers]

I have a utility service, 3 phase 4 wire. Grounded at point of connection. A generator has been added and the owner installed the generator himself. He grounded the generator. Should the generator and the serving utility both be grounded?

 

[roger]

The scenario you described would require a transfer switch that will switch the neutral. IOW'S you have a Separately Derived System.

 

[augie47]

Agree with roger but the term 'customer grounded the generator' did bring some possibilities. By that are you saying neutral output of the generator is grounded at the generator ? (as opposed to a ground rod being connected to the frame..a common customer install practice)

 

[LarryFine]

We can't tell whether you're talking about neutral bonding or equipment grounding.

 

[augie47]

We can't tell whether you're talking about neutral bonding or equipment grounding.

my point...you just worded it better

 

[jaggedben]

We can't tell whether you're talking about neutral bonding or equipment grounding.

Or an auxiliary electrode.

 

[tom baker]

Does your transfer switch, switch the neutral?
That determines what grounding and bonding is required, and where.

 

[David Rogers]

Thanks to all. Actually I knew there was something I didn't like about the way the generator was grounded. The idea that the neutral switching at the manual transfer switch is what clarifies it for me.

 

[LarryFine]

Either you switch the neutral and each source is bonded and earthed, or you don't switch the neutral and the load side is bonded and earthed.

 

[tom baker]

Either you switch the neutral and each source is bonded and earthed, or you don't switch the neutral and the load side is bonded and earthed.

Good explanation and avoiding the confusing term grounded

 

[qcroanoke]

Either you switch the neutral and each source is bonded and earthed, or you don't switch the neutral and the load side is bonded and earthed.

Are you saying bond on the transfer switch load side if not switching the neutral?
Which will work.
But I would bond in the utility disconnect in front of the transfer switch if I wasn't switching the neutral.