Is modifying a generator neutral connection a code violation if the manufacturer doesn't recommend it?

[Hv&Lv]

Most of the cheap ones have instructions from the manufacturer on how to unbond them.
So I take that as manufacturer recommended practice.

 

[R777V]

We’re not talking about bonding the ground rod to a generator though. We’re talking about unbonding the neutral to the frame of the generator so that we can use it as a non-separately derived system.

I guess I’m not seeing the bigger picture, can you explain what the advantage is, obviously the manufacturers have found that it was essential to do it, if the manufacturer said it was optional and in fact had their own instructions that UL and the code found to be ok I’d be all for it. Like one of the earlier posts mentioned,
(I think Generac ?)had instructions on how to mod their Generators, wouldn’t it make sense for liabilities sake to go that route? I’m at a loss give me the advantages and disadvantages. Not trying to argue for or against, just looking to be schooled where I don’t have expertise. Thanks


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[romex jockey]

I guess I’m not seeing the bigger picture

manufacturers trump NEC is via 110.3(B) is what i'm reading here

~RJ~

 

[shortcircuit2]

1. Connecting a "bonded" generator to a home electrical system...which already has a bond at the service creates a 2nd neutral to ground connection. This creates multiple paths for current flow.

2. Breaking the bond at the generator for connection to the home electrical system corrects issue in 1.

3. Careful now that the bond is lifted at the generator...because if the owner uses the generator away on say a worksite or camping trip...the bond is essential for the ground fault current path. The GFCI on the genertor no longer protects the user.

I have a generator with a floating neutral and I plug in a cord cap with an internal neutral to ground jumper to "re-bond" the generator for away from home uses.

 

[R777V]

I think I can see the light, at least with my cheaters on!


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[infinity]

1. Connecting a "bonded" generator to a home electrical system...which already has a bond at the service creates a 2nd neutral to ground connection. This creates multiple paths for current flow.

2. Breaking the bond at the generator for connection to the home electrical system corrects issue in 1.

3. Careful now that the bond is lifted at the generator...because if the owner uses the generator away on say a worksite or camping trip...the bond is essential for the ground fault current path. The GFCI on the genertor no longer protects the user.

I have a generator with a floating neutral and I plug in a cord cap with an internal neutral to ground jumper to "re-bond" the generator for away from home uses.

Wouldn't it be nice if the manufacturers simply put a switch go from bonded to unbonded and vice versa? Or better yet an auxiliary switch built into the 30 amp or 50 amp receptacle that unbonds the neutral when the plug is inserted.

 

[shortcircuit2]

Wouldn't it be nice if the manufacturers simply put a switch go from bonded to unbonded and vice versa? Or better yet an auxiliary switch built into the 30 amp or 50 amp receptacle that unbonds the neutral when the plug is inserted.

Yes that would be great for us professional qualified persons who understand its operation. But for the average person it may be a hazard.

I actually evaluate my generator customer as to whether I feel it will be safe for a portable generator connection. Some customers really should just have a permanent standby system.

 

[infinity]

I actually evaluate my generator customer as to whether I feel it will be safe for a portable generator connection. Some customers really should just have a permanent standby system.

I think that given the major cost difference between the two most people who are looking at portable generator solutions won't pay for a permanent backup systems. I know because I am one of them.

 

[shortcircuit2]

This guy on YOUTUBE does a great job explaining a floating neutral generator and its purpose...

You will see his OPINION at 23 minute mark on using a bonded generator with a bonded home service and some test examples of current flow on the equipment grounding conductor.

I'm still scratching my head on LarryFine's post #6 in this thread. If the EGC is not used in the cord from a bonded generator to the inlet for the home electrical system...there is still a path for fault current back to the generator on the neutral in the cord and on the home side there is the bond at the service so the path is there for all grounded equipment served by the homes electrical system thru the service panel neutral to ground bond.

 

[Fred B]

I've now been seeing generators of same size and mfg listed (advertised) as portable worksite generator with GFCI and another listed as a portable backup generator. There was no specifics on what other than the GFCI was different, they only remarked on OSHA requirements for jobsite with GFCI. Could the assumption be made that the one advertised as portable back up is without bonded N-G?

 

[shortcircuit2]

I think that given the major cost difference between the two most people who are looking at portable generator solutions won't pay for a permanent backup systems. I know because I am one of them.

Tottally AGREE. I have a portable tooo. But we are both qualified.

But...to name a few...

1. Will the homeowner be physically able to move the portable generator?
2. Does the homeowner understand that gasoline will go bad and they need to condition the fuel?
3. Will the homeowner exercise the generator?
4. Does the homeowner understand how important it is to keep the generator outside away from the home?
5. Can the homeowner maintain the generator?
6. Does the homeowner understand they can only use selected loads?
7. Will the homeowner recognize saftey issues when the generator gets old?

I have refused a portable install if I feel the HO can't fully understand these issues. I have had people struggle with the twistlock cord. I have had people call me during a storm becuse they couldn't remember the steps to connect a portable or my portable won't start (bad fuel)...

 

[don_resqcapt19]

manufacturers trump NEC is via 110.3(B) is what i'm reading here

~RJ~

The manufacturer's trump the NEC only where they require something more than what the NEC does. They cannot delete or lessen an NEC requirement.

 

[d0nut]

I see your point, but I’d like to know worst case scenario “do not do it”

In that scenario, you wouldn't be able to use that generator for your application. You would either need a generator that you could remove the neutral-ground bond, or you would need a switching mechanism that switched the neutral when you switched between the utility and your generator.

 

[jaggedben]

The manufacturer's trump the NEC only where they require something more than what the NEC does. They cannot delete or lessen an NEC requirement.

I don't know about that. It can go both ways. An unlisted assembly of components that might be subject to various NEC requirements may no longer be subject to all those same requirements when the assembly is listed. I agree that 110.3(B) doesn't completely trump NEC requirements but it does in some cases.

 

[ceb58]

So you’re saying all portable generators aren’t required to be listed? Therefore you can do whatever you want to it?

I think it's a matter of where it is sold. Some states do not require equipment to be listed.

 

[JEFF MILLAR]

Be very careful you could void the Generator warranty.