No grid grounding/bonding

[timselectric]

Moreover if you put the N/G bond downstream of the GFCI isn't the GFCI going to always see that as a ground fault and trip. I was actually thinking ironically he wouldn't be creating an unsafe condition because the GFCI would be tripping all the time

Actually, it would see a ground fault as nothing abnormal. Because it would rejoin the neutral before going through the GFCI.

 

[smr.ruby]

Actually, it would see a ground fault as nothing abnormal. Because it would rejoin the neutral before going through the GFCI.

Okay... I agree it is generally a bad idea and shouldn't be done but I just had to test this. I just connected neutral to ground downstream of a GFCI in my house and it tripped. I actually thought it would take some load to make it trip - it didn't or at least I didn't have to cause new load. If GFCI works by tripping when there is unmatched current between hot and neutral wouldn't adding ground as a path to take some of the current off of the neutral cause it to trip?

I'll admit the first time I tried it didn't trip and then I put a GFCI tester on that particular circuit and it appears I have a bad GFI, the tester won't trip it either - so I tested two others and they both tripped in the N/G connect scenario.

 

[hwy17]

There should only be one connection between earth and your grounding system

And then Article 680 comes along and builds a massive ufer appendage on the system.

 

[timselectric]

Okay... I agree it is generally a bad idea and shouldn't be done but I just had to test this. I just connected neutral to ground downstream of a GFCI in my house and it tripped. I actually thought it would take some load to make it trip - it didn't or at least I didn't have to cause new load. If GFCI works by tripping when there is unmatched current between hot and neutral wouldn't adding ground as a path to take some of the current off of the neutral cause it to trip?

I'll admit the first time I tried it didn't trip and then I put a GFCI tester on that particular circuit and it appears I have a bad GFI, the tester won't trip it either - so I tested two others and they both tripped in the N/G connect scenario.

The test was flawed. Because you have two N/G bonds.
One upstream and one downstream.

 

[timselectric]

And then Article 680 comes along and builds a massive ufer appendage on the system.

It's still one point of connection. (The main ground bar)
All earth connections (rod/plate, ufer, water, gas) should come together at one connection with the grounding system.

 

[smr.ruby]

The test was flawed. Because you have two N/G bonds.
One upstream and one downstream.

Fair, I presume you are right but that leaves something I don't understand then about why the upstream one matters at all... darn it... more mystery oh well.

 

[timselectric]

Fair, I presume you are right but that leaves something I don't understand then about why the upstream one matters at all... darn it... more mystery oh well.

The double bond you created. Gave a parallel path for neutral current around the GFCI. This is why it trips emidiatly.
With no bond upstream and a bond downstream. All neutral and fault current will travel through the GFCI neutral. And appear as normal (balanced) to the GFCI.

 

[timselectric]

If you want to test it correctly. Remove upstream grounding from the GFCI. And bond downstream.

 

[smr.ruby]

If you want to test it correctly. Remove upstream grounding from the GFCI. And bond downstream.

I think I have my head around what you are saying. I was testing at my house though and probably don't want to remove the panel bond for fun. But I could give it a go on my offgrid solar system next time I'm there

 

[timselectric]

I think I have my head around what you are saying. I was testing at my house though and probably don't want to remove the panel bond for fun. But I could give it a go on my offgrid solar system next time I'm there

No need to remove the panel bond.
Just remove the upstream ground from the GFCI location. And test it downstream.

 

[Steve_S]

Poor Nan, she asked for one thing and this pummeling over ground Fault & other stuff MURDERED THE THREAD....

If you guys want to argue about GFI, CGFI, GCFI and the variants & related applications START A THREAD ON IT !

 

[theoldwizard1]

Ultimately it depends on what inverter/generator you're talking about. Personally I think its easiest to set up the G/N bond in the panel.

You want ONE BOND for the entire system ! Best place to do it is in the main panel.