Open Neutral and failed transfer switch
we purchased a 201203 cyclone 3110 last Fall.This summer while at the beach, we came back to find our electric off and bedroom tv, central vac, and microwave fried. Before telling the campground what ...
Forum Discussion
CA Traveler wrote:
So why didn't the PI HW50 protect you? The answer is simple: The problem occurred after the HW50.
I agree. The HW50 should trip if there is an open neutral leading up to it. Since it didn't, the problem would seem to be after the HW50. I suspect a loose or broken neutral line running into the main breaker panel, or a poor connection on the breaker box neutral bar.
It sounds like the tech is using a volt meter to check for voltage changes while examining the neutral connections. He probably has most/all loads turned off to prevent damage to appliances during testing. Keep in mind that while an open neutral can cause wide voltage swings up or down on the individual power legs, it will only do that if one leg is more heavily loaded than the other. The voltage swing is directly proportional to the difference in loads. So if he has most/all loads turned off, it may not be a valid test. Perhaps a better test is to disconnect all power sources, and use a multimeter to measure neutral conductor resistance while manipulating wires and connections?
I'm glad to hear that the OP put the HW50 after the transfer switch. That always made more sense to me than putting it before. Since the unit can only protect against problems that happen before the unit (on the input side) it would seem to give the most protection after the transfer switch. If you put it before the transfer switch, the unit will give you no protection against a transfer switch problem (like a burned neutral contact) nor will it give any protection against a generator fault (like a blown out voltage regulator.) The typical reaction is that it should be before the transfer switch to protect the switch, but there really isn't much in the transfer switch that can be damaged by wiring problems, while there is plenty inside the switch to cause wiring problems. It doesn't make sense to me to spend hundreds of dollars to protect a device that costs much less, when that device can actually cause more problems than it receives.
