[villagetinker]

Is this an above ground or in ground SPA? The circuit breaker is a GFCI type, and will trip for any ground fault from the circuit breaker panel to the spa. There should be a disconnect box near the spa (I am assuming this is a 240 volt connection). If this got wet, it could be the cause of the problem. If this is an in ground spa, can you see if there is water sitting in the pit around the spa? If so, any small nick in any of the wiring could be causing the fault. If all of the side panels were not properly in place, some rain water may have gotten inside the unit. Mine has a solid base pan (with I assume drain holes, but I have never seen them), and if water were sitting in the pan, this could cause a fault with the wiring.
Now as mentioned above, you will need to have a suitably licensed technician work on this, I am a retired profession electrical engineer, and I doubt I would try this on my own spa. If you are interested, you can send me a PM, and I can tell you a few items to try which may locate the area where the problem is and may shorten your repair time. None of these require any electrical work.