Generac auto transfer panel

[goldstar]

I had a service call yesterday where a tree came down and pulled the service conductors off the side of a house. The phase conductors never came apart but the neutral was completely severed. The transfer panel didn't transfer and start the generator. The HO claimed that everything in his house was operative and everything with digital displays was working fine and nothing got toasted. Usually when the reference to the pole transformer neutral is lost excessive voltages to a residence cause a lot of damage. Obviously the neutral somehow got back-fed and allowed the HO to think that things were normal.

Anyway, if anyone else has had this experience with Generac would you please share your thoughts ? Did the transfer switch see the neutral from the ground rods and/or the water main ground ? The main utility pole with the transformer is about 150' away from the house with a 2nd pole with a support hook is half-way on the HO's property.

 

[infinity]

If the water piping system is shared among houses then it's probable that the neutral current just found a path back through the piping and through the neighbors neutral to the POCO transformer and the system operated normally.

 

[Fred B]

I had a service call yesterday where a tree came down and pulled the service conductors off the side of a house. The phase conductors never came apart but the neutral was completely severed. The transfer panel didn't transfer and start the generator. The HO claimed that everything in his house was operative and everything with digital displays was working fine and nothing got toasted. Usually when the reference to the pole transformer neutral is lost excessive voltages to a residence cause a lot of damage. Obviously the neutral somehow got back-fed and allowed the HO to think that things were normal.

Anyway, if anyone else has had this experience with Generac would you please share your thoughts ? Did the transfer switch see the neutral from the ground rods and/or the water main ground ? The main utility pole with the transformer is about 150' away from the house with a 2nd pole with a support hook is half-way on the HO's property.

Dont think this had anything to do with generac, unless ground neutral bonding wasn't properly done, then only minimally in this instance.
I've seen significant load imbalance on single phase caused by dropped or damaged neutral where most items continued to function until a large unbalanced load came on. Neutral is only carrying the unbalanced loads so it could happen. And any unbalance might have been able to be obsorbed by the ground cable if the ground resistance was lower than other time (very wet soil), proximity transformer, etc.
This is one way you get "stray" voltage on your ground wire. My bet would be the neighbors where getting some odd behavior on their systems. I would say the only good thing to be seen from this is this panel had some very good load balance. Also likely would have seen voltage to ground variances depending on loads coming on and off.

 

[hillbilly1]

Generac only senses the hots, not the neutral to hot voltage, but that being said, like others have said, the GEC was probably low enough resistance for the neutral current to flow back on it.