Neutral wire broken 120v circuit

[KVA]

A neutral wire that is broken on a 120v circuit that is arching won't trip a standard breaker but it will with an AFCI correct? It's a series arc fault not a N to G fault.

 

[don_resqcapt19]

A neutral wire that is broken on a 120v circuit that is arching won't trip a standard breaker but it will with an AFCI correct? It's a series arc fault not a N to G fault.

It is very unlikely to trip a standard breaker as the current will be limited by the load and the impedance of the arc to a value that would be below the rating of the breaker.

The intent is that an AFCI would clear that fault.

 

[K8MHZ]

It is very unlikely to trip a standard breaker as the current will be limited by the load and the impedance of the arc to a value that would be below the rating of the breaker.

The intent is that an AFCI would clear that fault.

Intention is one thing, proof is another.

I wouldn't bet my life that an AFCI would trip during a series arc in the neutral conductor. I am pretty sure that the 'proof' that Eaton shows using their big arc making machine is not on the neutral.

 

[GoldDigger]

It is very unlikely to trip a standard breaker as the current will be limited by the load and the impedance of the arc to a value that would be below the rating of the breaker.

The intent is that an AFCI would clear that fault.

But the series arc detection of an AFCI will not even be active unless the arc current, which will be lower than the load current, is above the current threshold (~7A??)

 

[don_resqcapt19]

Intention is one thing, proof is another.

I wouldn't bet my life that an AFCI would trip during a series arc in the neutral conductor. I am pretty sure that the 'proof' that Eaton shows using their big arc making machine is not on the neutral.

I said "intent" because I have not been convinced that a self sustaining arc can even exist at dwelling unit voltages.

 

[don_resqcapt19]

But the series arc detection of an AFCI will not even be active unless the arc current, which will be lower than the load current, is above the current threshold (~7A??)

I think it is 5 amps for series arc detection and 75 amps for parallel arc detection.

 

[K8MHZ]

I said "intent" because I have not been convinced that a self sustaining arc can even exist at dwelling unit voltages.

You aren't the only one.

 

[JFletcher]

A neutral wire that is broken on a 120v circuit that is arching won't trip a standard breaker but it will with an AFCI correct? It's a series arc fault not a N to G fault.

I doubt it. Ive seen afci video of a 1500W heater made to arc (by touching/lifting ungrounded conductor from the receptacle it was plugged into) and the breaker never tripped.

 

[K8MHZ]

I doubt it. Ive seen afci video of a 1500W heater made to arc (by touching/lifting ungrounded conductor from the receptacle it was plugged into) and the breaker never tripped.

I have actually done that. Granted, it was years ago before Michigan ditched the requirement for them, but I did the same experiment on the first AFCI breaker I ever saw. I could arc and spark all day through the portable heater as a load and the AFCI wouldn't trip.