Hot Tub Breaker Tripped due to High Temperature Outside?

[hightechburrito]

I went outside today to test my water and noticed the breaker had tripped at the sub panel. My last test was 2 days before and I haven’t used it since then so I don’t have any way to know when it tripped exactly. Flipped it back on and it’s working fine.

The outside temperature has been really high in the last few days (over 110F the last two days), and the sub panel is on a south facing wall (so it sits in the full sun all day long). Due to the outside temperature it’s very unlikely that the heater was needed at all, so I don’t think that the hot tub really pulled too much current to cause the breaker to trip.

I’ve had the tub for over a year with no issues, and this is the first time it been this hot since I’ve had it. Anyone else ever have a breaker trip when it gets super hot outside?

 

[Mdragger88]

I have not personally, but sounds like you may have a weak breaker. Is it new like the tub? You definitely want to rule out any possible over current conditions etc. before just assuming & replacing the breaker though.

 

[wireform]

I wonder the fact it's so hot and the electrical grid is probably up there in usage they may be lowering the voltage a little and then the amperage goes up a little when that happens. Maybe the breaker is borderline line so it trips. I had this 2 weeks ago at my job with the hot weather and the grid slightly lowered voltage causing the amperage to go up and blew my cartridge fuses at one piece of equipment.

 

[hightechburrito]

I have not personally, but sounds like you may have a weak breaker. Is it new like the tub? You definitely want to rule out any possible over current conditions etc. before just assuming & replacing the breaker though.

The breaker is the same age as the tub (little over a year).

How would I rule out over current issues? Run the tub and see if it happens again? Only the low speed pump would have run in the last day or so (high speed pump only runs manually, and it’s hot enough that the heater shouldn’t have turned on).

 

[wireform]

You can amp out one of the wires for the magic number.

 

[hightechburrito]

I wonder the fact it's so hot and the electrical grid is probably up there in usage they may be lowering the voltage a little and then the amperage goes up a little when that happens. Maybe the breaker is borderline line so it trips. I had this 2 weeks ago at my job with the hot weather and the grid slightly lowered voltage causing the amperage to go up and blew my cartridge fuses at one piece of equipment.

Thanks.

Reading online elsewhere I see a lot of people saying this has happened to them, so it kinda makes sense.

I also see 140F tossed around as a minimum temperature where a breaker should trip. I can see the inside of the sub panel getting there in direct sun when it’s 115F outside.

If it doesn’t keep happening in “normal” ambient temperatures should I not worry about it?

 

[wireform]

You're confusing 2 separate things. The 140F temp is one way to cook it but what I explained is an electrical problem not related to the physical temp of the circuit breaker but rather it's rating. Circuit breakers are to be used up to 80% of its rating but possibly due to the hot temps and the amount of stress on the electrical grid they may have lowered the voltage which inturn raises the amperage. So now in this scenario you may be close to peak amperage of the circuit breaker causing it to trip.

 

[hightechburrito]

You're confusing 2 separate things. The 140F temp is one way to cook it but what I explained is an electrical problem not related to the physical temp of the circuit breaker but rather it's rating. Circuit breakers are to be used up to 80% of its rating but possibly due to the hot temps and the amount of stress on the electrical grid they may have lowered the voltage which inturn raises the amperage. So now in this scenario you may be close to peak amperage of the circuit breaker causing it to trip.

Do I do anything about it if this is what happened? Or just accept that it may trip when it’s 115F outside?

 

[hightechburrito]

Ambient temps are just a little cooler today (just under 110F), and the inside of the subpanel was over 140F when I measured with a non-contact IR thermometer. Makes sense to me that the breaker might trip at a lower than expected current (on top of the issue brought up my wireform).

Breaker hasn't tripped again, and I also reset it at 10am so it will run it's 2 hour filter cycle at 10am and 10pm. This avoids both the peak electricity cost and the peak temperature times of the day for it to be running.