Here is my situation.
Two years ago I tore out the flooring in our second-floor master bathroom and installed ceramic tile. Under the ceramic tile, I first replaced the sub-flooring, put in a floor heating element, covered it with self leveling concrete, then laid the tile on top of that. It is all controlled with a programmable unit where I set the desired temperature and time of day that I want the floor heated. It is a wonderful experience to have a heated floor during these frigid Wisconsin winters.
This is the third winter, and it all has worked just fine – until last week. Examining the instruction sheet, the control unit is detecting a ground fault and is shutting off the power to the heating element.
a) How could the system suddenly develop a ground fault? It is completely buried in concrete.
b) The control unit might be defective, but before I purchase an expensive (~$80) replacement control unit, I want to verify that there really is a ground fault. How would I do that? What piece of equipment would I need?
c) If there really is a ground fault, any ideas on what I might do to find it? I really, really, REALLY do not want to tear up the tile and concrete.
I know I could hire an electrician to come out and do this testing, but I’m pretty handy. Unless the equipment I need to verify the ground fault is expensive, I’d like to avoid paying an electrician to do something I can do myself.