Mastertemp400 breaker tripping while heater is OFF

[James L.]

Thanks for your replies.
The wire nut connection of the wires from the breaker and the main power wires in the heater looked dirty and corroded (black,red,green; 16 awg). I cut off the corroded ends and used water proof Dryconn wire nut connectors to splice them together. These are the only wires anywhere in the whole system that looked compromised. All other terminals, connections, wires, grounds, looked fine. Heater breaker has not tripped since everything dried out. This is the first time this has happened since pool was built in 2019, so I'm thinking possibly that could have been enough time for those corroded connections to start leaking current.
BTW, the 16 gauge black,red,green wires that came factory wired inside the heater look silver, like aluminum wires. Those are tinned copper wires, not aluminum, right?

 

[James L.]

I also just tested for current leakage at the heater. Results: no leakage.
I also routed wires in heater so that they are not in moisture prone areas inside the cabinet.

 

[JamesW]

I also just tested for current leakage at the heater. Results: no leakage.

Can you describe the test procedure?

 

[James L.]

I read a few sites from electrical businesses. They had several ways from simple to more comprehensive (leakage clamp meter). With multimeter set to continuity and circuit de-energized, touch suspected wire(s) with red probe and black to known ground. If get continuity, have leakage. So simple yes/no, not how much.
Also, multimeter set at 2M ohm. Black to known ground, red to suspected wire. Got OL.
Also, set mm to 600v ac; black on known ground, red on suspected wire. Got zero.
Best I could do w/o a leakage current clamp meter. And I’m sure there are lots of different ways to shoot holes through these simple methods.
Bottom line is I’ll see if heater breaker trips again and then call an electrician, or buy a leakage current clamp meter . As of right now, no tripping.
All that being said, I am open to any suggestions you guys may have. Thanks.

 

[wireform]

Not sure if you answered which circuit breaker is the heater as the top two are the recommended ones used for pool pumps and the like but the third last one is different and may be more sensitive in the setup.

 

[James L.]

Each pump, heater, has its own conduit from the control box to that device. Each breaker’s wires go down only that one specific conduit to each device. The breaker that tripped has wires that only go down the conduit that goes to the heater.

 

[James L.]

And I am out of town so I can’t see the panel presently, so I cannot say with confidence how many breakers from the top it is. It is not the bottom double pole breaker.