I am installing a heating system underneath ceramic tile. The system will only pull about 5 amps and I want to get my juice from an existing source. The wirlpool is on a circuit of it's own 20/amp breaker and it is only pulling about 7-8 amps. So far so good, However the breaker is a gfci breaker at the box, The prostat controller that I am putting in has its own gfci built in. So if I tie into this, will this cause any problems like one tripping the other often and possibly causing the prostat controller to go bad and need to be replaced,( as I was told by some kid in the technical dept of the heat system that I am using that he thought that would be the case).

Thanks for any help!

It should be fine, any fault will remove hot and neutral.
If it somehow it was a problem, maybe you could put a regular breaker in the panel.

The answer to your question is yes. If you have two GFCI plugs on one circuit and one trips the other will also trip.

I hope this helps you out.

JP
Patco Lamp

My experience has shown me 1 or the other will trip. In some cases both will trip.
That is if there is a fault.

I totally agree with start too. It's based on component tolerences and how bad the fault is. The same is true with breakers in series. They each have a slightly different time trip curve incurred by manufacturing, so either or both might trip.

Thanks Guys, you were a big help. I am going to get my juice from another breaker, and not even mess with it. I had to know now because I can't change it once it's finished, the probe will be embedded in thinset.