generator bonding

Status
Not open for further replies.
S

sparkync

Senior Member
Location
North Carolina
If the neutral and grounding conductor are tied together at the "Main Panel" which I know is required, will the "gas generator" that is to supply power to the house during power failure, have to be configured as a "floating neutral"(separating the neutral from the ground), and will a ground rod at the generator be required to tie the grounding conductor too? I read on the site of the generator in question that this is the procedure. I just wanted to make sure they were right before I installed wiring ect.
Thanks for your input.
 
You have two choices a separately derived system (SDS) or a non-SDS. With the non-SDS the neutral is not bonded in the generator and no ground rod or any other connection to an electrode is required for the generator because the GES of the house is still connected. For a portable generator with a factory bonded neutral you would need to remove the bond and use a 4-wire cord to the inlet. Also a sign is required at the inlet stating what kind of system you have and a sign is required at the panel stating that there is an alternate power source.
 
Also I'm a little confused with the neutral in the 4 wire Cord hook up. If the neutral in the generator is disconnected, then the neutral wire in the cord is doing nothing for the house. I understand that the neutral and ground are bonded at the main panel and that the "ground wire" will be serving as the "neutral", but why is "4 wire" needed? Probably a dumb question here, maybe I'm a little "dumb". Or confused would be a better word:)
 
I'm assuming that this is a 120/240 volt generator so the receptacle that you're plugging the cord into on the generator will typically be a 30 amps, L14-30R, 4 wire receptacle. That will provide H-H-N-EGC in the cord from the receptacle. The connection to the GES at the house will still be connected whether you're under generator power or utility power so no grounding electrode (you mentioned rod) is required at the generator.
 
sparkync said:
Ok, thanks a lot. Yes it is a L14-30R, 4 wire receptacle.
Click to expand...
IMO this is the best setup to use a portable generator for this purpose. Disconnect the bonding jumper from ground to neutral and use the house GES for the electrodes.
 
Last edited:
sparkync said:
If the neutral in the generator is disconnected, then the neutral wire in the cord is doing nothing for the house.
Click to expand...

Actually, you do not disconnect the neutral conductor in the generator. You just disconnect the neutral-ground bond in the generator.
 
Just a word to the wise, make sure you take a close look at the specs of the portable generator you buy. Some are supplied with ALL receptacles being ground fault protected. That includes the L14-30R. As soon as you plug the cord in and turn on the breaker on the generator, the GFI on the generator will trip and knock out the power output.
 
goldstar said:
Just a word to the wise, make sure you take a close look at the specs of the portable generator you buy. Some are supplied with ALL receptacles being ground fault protected. That includes the L14-30R. As soon as you plug the cord in and turn on the breaker on the generator, the GFI on the generator will trip and knock out the power output.
Click to expand...
While you're disconnecting the bonded neutral you'll have to disconnect that too. :)
 
infinity said:
While you're disconnecting the bonded neutral you'll have to disconnect that too. :)
Click to expand...
The last one I came across had one of these where the power wiring was running through the CT on the GFCI:

LEVITON 240 VOLT HIGH CURRENT GFCI | The Spa Works

Leviton 240 Volt High Current GFCI, Panel Mount. P/N 8895E THIS ITEM HAS BEEN DISCONTINUED WITH NO REPLACEMENT
www.thespaworks.com

You actually have to disconnect the 30A power wiring from the receptacle, remove the wiring from the loop of the CT and re-connect it to the receptacle. :cool:

Questions :
  1. Are you voiding any warranties ?
  2. Are you committing any NEC crimes ?
  3. Do you care ? :)
 
goldstar said:
The last one I came across had one of these where the power wiring was running through the CT on the GFCI:

LEVITON 240 VOLT HIGH CURRENT GFCI | The Spa Works

Leviton 240 Volt High Current GFCI, Panel Mount. P/N 8895E THIS ITEM HAS BEEN DISCONTINUED WITH NO REPLACEMENT
www.thespaworks.com

You actually have to disconnect the 30A power wiring from the receptacle, remove the wiring from the loop of the CT and re-connect it to the receptacle. :cool:

Questions :
  1. Are you voiding any warranties ?
  2. Are you committing any NEC crimes ?
  3. Do you care ? :)
Click to expand...
1) yes but you have no choice
2) probably not unless you're quoting something in Article 110
3) if you want it to work correctly, not really :sneaky:
 
Status
Not open for further replies.
Top