Hi. I would appreciate some help troubleshooting this GFCI problem.
In the main inside box there is a 50A two pole GFCI feeding an exterior SPA and nothing else. The control system is a brand new unit from Spadepot. The element is also brand new, 5.5kW @ 220V. Except for the element each part of the system can be configured for 110 or 220. I'm using a 110V motor, blower, and ozonator. This is 4 wires - L1, L2, Neutral and ground. Only the heating element runs on 220. After 10-20 minutes of operation the GFCI trips. Disconnecting the heating element stops the tripping. Reconfiguring the tub to run on 110 also stops the tripping.
The element measures about 12 ohms terminal to terminal. I mounted the element in the tube and know it is centered (not touching the tube). If the element was shorted I would expect a trip due to over current but it should only be using less than 20A. It is a good idea to use a current probe to prove it isn't a breaker trip, instead of a GFI trip. I will do that, but I think it is not over current.