Have a head scratcher.
Building an electric brew kettle using a 5500 watt hot water heating element.

Built a subpanel and control box that plugs into my dryer outlet. Using a 50 amp gfci spa panel for some don't electrocute myself protection. With a potentiometer controlled solid state relay to control the power into the element.



anyway
fired it up 2 nights ago and ran some water up to a boil everything worked perfectly.

Fast forward to today and I plugged it in and it tripped the breaker immediately. Not the breaker in the main panel but just my gfci. Ohmed out everything have no continuity where it shouldn't be all connections right and tight

I then disconnected all wiring on the outlet side of the breaker and it still trips. Measured 2 hot legs at the wall plug and getting 124.6 and 126.1 volts. Same volt reading on both the ground and neutral.


Is that voltage difference enough to trip the breaker? Any other ideas as to what could be causing the issue?