Charles wrote:
"cold ribs" wrote in message
news:IOKpj.19889$Ou1.14388@trnddc07...
Hi,

I have a spa outside my home. It was installed by a certified
electrician, etc. It used to trip the breaker on occasion (60amp, 2
pole), like if we left the high power jets on for 20 minutes or so. No
big deal.

We just had the main CPU of the spa replaced and now it trips daily,
regardless of jet usage. The guy who put in the new CPU said the
electrician who installed the spa initially used 8ga wire instead of 6ga,
which he should have used.

Would this be the main reason for the tripping that used to occur on
occasion? And, if so, why would it trip more frequently now?

The guy who put in the CPU is finger-pointing to get off the hook!

A smaller gage wire could actually reduce tripping since it adds resistance
and thus reduces current flow.

There is more to your problem than can be easily established by the
information you provided.

Duty cycles are perhaps the issue here. Circuit breakers can tolerate an
overload for a period of time depending on the degree of the overload. A
20% overload is going to take a long time to trip the breaker compared to a
60% overload. The magnetic trip is very fast, but the thermal trip is slow
and is a function of the degree of overload.



I had the spa off for several days out of frustration - left the breaker
off. Turned it back on, and it was fine for nearly 2 days. Now, it
trips daily. It'll stay when you turn it back on (doesn't immediately
switch back off) on but then trip at some point during the day.

Does this sound like the "thermal trip" you described?