GFCI Trips when set temperature is achieved

[palmettospecialties]

I have a 110 v, spa, one two speed pump, no blower or ozone generator. Everything works great until the water reaches the set temperature, at which time gfci trips. Any advice would be greatly appreciated.

[DaveMc]

You know since this is an electrical question I would suggest this site--- http://www.diychatroom.com/f18/  ---as electricians will answer your questions---and sometimes they will debate among themselves the answer--but like this site it is a a very good resource.

[Isaac-1]

Is this a GFCI outlet that trips, a GFCI breaker, or is it the GFCI on the cord?  In any case there are two possibilities, one it is doing its job, or it has went bad and is now overly sensitive.  In my general experience dealing with GFCI equipment it could be either one.

[wingizzmo]

Also brings to mind something that has happened to me before If the cord on the spa has a GFCI built into it and your plugging into a outside outlet or breaker that is also a GFCI that could be an issue .

[palmettospecialties]

There are 2 GFCIs, one on tub, one in breaker box. The one in the breaker box tripped several times initially. I connected hot tub to a non GFCI protected outlet, and the GFCI on the tub tripped, indicating to me that there is a problem and that the GFCIs are working correctly.

[Dr. Spa™ Ret.]

It's possible that your heater element is failing. It could have a microscopic hole in it, that expands (enlarges) as it heats up. When it gets hot enough and has enlarged far enough, it allows enough water to get in to cause a short, tripping the GFCI.

[palmettospecialties]

I am replacing heating element, will let you know if that does it. Thank You!

[DaveMc]

Looks like Dr Spa nails it again--also 3 responses here--- http://www.diychatroom.com/f18/gfci-trips-207503/

[clover]

Before replacing the heater, let's test it to see if it is really the problem.  This is easily accomplished by simply disconnecting the heater wires and see if the GFCI reacts differently. 

If it still trips, disconnect each electrical motor, or accessory one at a time to see if the GFCI holds.  IF and When, the GFCI holds, reconnect each individual item that you disconnected to verify the single item as being the culprit.

If you have an ohm's meter, measure resistance to ground of each electrical component.  There should be no resistance to ground from any of the power connections.

[DaveMc]

Clover
Great---clear and concise advice--to confirm the actual culprit--if he does that he will be positive he has found the fault---otherwise replacing items is a matter of trial and error.
Dr Spas answer was quite logical---may be he has ran in to that in the past.
David