The Streets wrote:
I have a 30amp 240 volt circuit breaker for the heater in a hot tub.

With the circuit breaker off, the case temperature is 83 deg F (the
ambient temperature) measured with an IR temperature sensor.

I turn on the breaker and the hot tub. After about 10 minutes,
the case temperature is 99 deg F.

Does this sound normal?

The breaker doesn't trip, but I don't have a reading on actual
current flow.




Don't know about the exact temp but a CB can be warm to the touch.
Make sure all the connections are tight and that you have the proper
size wire. Minimum size for 30A breaker is #10.
You might want to check the name plate labels on the heater to verify
that the breaker/wiring is sized properly.
Kevin