Did a service call on a hot tub that has an internal gfi and is also being fed with a 240 volt gfi protected circuit. The pump runs but as soon as you turn the thermostat on to energize the elements the internal gfi opens. Tried it several times first two, tub gfi opens, last few times it was the breaker. Told the owner to call the spa co. She told me that they came out and said the problem was in the line. Call the tech myself, and he said that there was no need for the gfi breaker since the tub had it's own protection. Fine. Then he said that the problem was the fact that a gfi was being fed by another gfi. Huh? Why would the downstream gfi trip? And why only when the elements were charged. Pump runs fine. He didnt answer he just said to replace the gfi breaker with a standard breaker. Am i missing something here?? It has been a long day, and this was the end of the day. Thanx John
Some different brands of gfi's do not work well together. I have had the same problem. I chose to replace the gfi at the spa with the same brand as was in the panel. Not the cheapest way to go but at least the panel gfi still protects the entire circuit.
Its been a while, but I remember having problems with GFCIs that are downstream from another GFCI on the same circuit. Since then I have always avoided the situation by installing a GFCI breaker for the whole ciruit or installing GFCI Recps only where required in the circuit and and never downstreaming to another GFCI recp.
There is no reason that GFCIs in series should cause any type of problems. The only problem is finding which one tripped to reset it. The one with the lowest actual trip setting will trip first. In some cases they both may trip, but they do not communicate or iterfer with each other. Don