Lost neutral question

[OK Sparky 93]

I was watching one of Mikes videos, where I believe he was saying that if you drove an isolated ground rod and connected a wire to a breaker and connected to or attempted to connect to that ground rod, that the breaker would not trip.

I may not recall that correctly, but if I am, then if in correctly installed system, you had two abnormal occurrences, of a ground fault and a lost neutral, then would the breaker of that faulted circuit trip?

 

[ptonsparky]

I was watching one of Mikes videos, where I believe he was saying that if you drove an isolated ground rod and connected a wire to a breaker and connected to or attempted to connect to that ground rod, that the breaker would not trip.

I may not recall that correctly, but if I am, then if in correctly installed system, you had two abnormal occurrences, of a ground fault and a lost neutral, then would the breaker of that faulted circuit trip?

No.

 

[ptonsparky]

Bonding to a neighborhood metallic water piping system would allow it to trip.

 

[OK Sparky 93]

Bonding to a neighborhood metallic water piping system would allow it to trip.

Is this because of more contact to the earth?

 

[ptonsparky]

Is this because of more contact to the earth?

No, the neighbors neutral will be bonded to it. Current will flow along the pipes back to the transformer. This occurs even without a fault or open neutral at one of the services and is normal.

 

[retirede]

I was watching one of Mikes videos, where I believe he was saying that if you drove an isolated ground rod and connected a wire to a breaker and connected to or attempted to connect to that ground rod, that the breaker would not trip.

I may not recall that correctly, but if I am, then if in correctly installed system, you had two abnormal occurrences, of a ground fault and a lost neutral, then would the breaker of that faulted circuit trip?

It would depend on the relative position in the circuit of the fault vs where the break in the neutral is.

 

[OK Sparky 93]

Lost utility neutral

 

[jaggedben]

Bonding to a neighborhood metallic water piping system would allow it to trip.

Probably. But not if what you said in post #5 happens not to be true.

 

[jaggedben]

Lost utility neutral

With a lost utility neutral, a ground rod at the service becomes a lot like the isolated, enegized ground rod in Mike's example. On a split-phase 120/240V service, essentially both hot legs are connected to the rod through the loads (if plugged in or turned on) and the service equipment neutral bar. If only loads on L1 are turned on, then it's quite the same, and the rod may develop a step potential just like in Mike's example. If loads on L1 and L2 are on, then the step potential will depend on the relative resistances of the loads. Just another reason that a lost neutral is a really bad situation.

 

[retirede]

Lost utility neutral

If you have a ground fault on one branch circuit in conjunction with an open utility neutral, the breaker may trip, depending on what loads are energized on the opposite leg. Loads on the opposite leg are likely to be damaged, as well.

But the presence (or lack) of a ground rod doesn’t have any effect on the scenario.

 

[Seven-Delta-FortyOne]

It is a common misunderstanding that a ground rod has something (or anything) to do with clearing a ground fault. It does not.

Current returns on all available paths, inversely proportionally to resistance, back to the source. The grounded conductor is what clears ground faults.

I actually overheard a guy in the electrical department of the local supply house telling a customer that “electricity is trying to get back to ground”.

 

[Willie B]

It is a common misunderstanding that a ground rod has something (or anything) to do with clearing a ground fault. It does not.

Current returns on all available paths, inversely proportionally to resistance, back to the source. The grounded conductor is what clears ground faults.

I actually overheard a guy in the electrical department of the local supply house telling a customer that “electricity is trying to get back to ground”.

Not a surprise. Selling electrical supplies does not get the training an electrician gets.
I've been told by a licensed electrician who has taught in State of Vermont night school, now he works the electrical department in Home Depot. He told me there is no such thing as schedule 80 PVC conduit. Saw him selling ALSER2 cable to people for direct burial.

 

[Fred B]

He told me there is no such thing as schedule 80 PVC conduit.

Maybe not at the HD where he worked. Generally can't find it there.

 

[kwired]

Maybe not at the HD where he worked. Generally can't find it there.

Can't speak much about HD. Menards is more common around here, they never have schedule 80 in the pipe rack inside the store but usually do have it in the outside yard.