Hi I am installing a new to me spa. I grounded the circuit at the main panel and installed the tub subpanel with gfi. I wanted to test my work before I hooked up the tub, and no dice. Even without any load, without even wires hooked up, it wouldn't stay on. So I thought, okay, there's a fault in my panel somewhere. So I isolated the ground and neutral, giving the subpanel its own local ground and taking it off the main panel ground/neutral. The ground is a normal 8ft ground rod fully driven. No dice. Still trips. What to do? It can't be the new gfi--can it? And if the subpanel ground bar is only hooked to ground and nothing else...how could there be a fault?

Tia, Dumbfounded...

I think I may have discovered the prob. Was a new ground rod and now that we've got some rain it seems to be staying on and tests okay. Could this be it?

It could be. Grounding rods are supposed to be drove deep and about 10 feet from a house and shelter. They need moisture to work properly.