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Old 04-09-2009, 11:02 AM
Algernon Algernon is offline
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Electrical -- how do I confirm / find a ground fault?

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.
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Old 04-09-2009, 11:22 AM
Gbro Gbro is offline
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The use of a "Megger" may be required to troubleshoot your problem. At the cost of one of these, calling an Electrician would be logical
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Old 04-09-2009, 01:28 PM
Algernon Algernon is offline
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Quote:
Originally Posted by Gbro View Post
The use of a "Megger" may be required to troubleshoot your problem. At the cost of one of these, calling an Electrician would be logical
Holy crap! Well, I'm definitely not investing in a Megger.
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Old 04-09-2009, 02:57 PM
MrFloppy MrFloppy is offline
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You can buy a 'Megger' for a lot less. Megger is a brand name. What you need is an insulation tester.

Here's one on eBay for $20. It's a hand crank too. A REAL Megger: http://tinyurl.com/cyceb7

Unlike a multimeter which only puts a few millivolts down a wire, a Megger typically puts 250, 500 or 1000V down a wire. If there is a leak to ground, it will show up.
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