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.
I don't know the exect temperature rise you should be getting , but it is probably normal. Fuses and breakers work on temperature rise. They introduce a small resistance in the circuit and heat up as more current is drawn. When they reach a predetermined temperature, the fuse element will melt or the breaker will trip. Even the wires going to the hot tub heater will get hot. The temperature rise will be of a safe value if the wiring is sized correctly and the insulation of the wire is rated for it.
If you look at a fuse or breaker chart, you will see that they do not trip at exectally what they are rated for . That is your 30 amp breaker may trip in two days if you draw 30.5 amps and one hour if you draw 32 amps and in 30 seconds if you draw 34 amps and maybe 5 seconds if you draw 50 amps. You have to look at the chart to see exectally how long it will take to trip depending on the current. Also the temperture around the breaker will have a small effect on the time. If it is very hot, (say a breaker box in the sun) they could trip at 25 amps instead of 30.
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
Could be normal, I f it was bothering me I would check my hot tub manual to find out the reccomended size of the breaker. Mine was wired wrong with a 30A breaker when it should have been a 50A and it would get fairly warm but it did not trip.
Jimmie
It should not be that warm, maybe the HT has a short,
Check amp draw with a clamp on meter
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