Locating exact break in heating wire under floor tiles

Hi All

I need a schematic for a gadget that can locate the EXACT point where a heating wire element is broken beneath floor tiles . I have built many detectors like FOX & HOUND tracers , SIGNAL GENERATORS & DETECTORS etc. All work ok if i probe VERY near the wire , but fail hopelessly once the wire is under a floor tile with cement , screet etc.

I am currently using an imported frequency generator & detector , but i cannot copy the circuit as the warranty seals are intact & my manager refuses to let me tamper with them

This unit works extremely well , can anyone please help in this regard ?

Any help will be appreciated

BTW : GREAT FORUM

Try a google on Time Domain reflectometer. You might find a DIY TDR. I did a quick search and found a few, can't say how well they would work.

A metal detector can yield a good path of the heating element but will not reveal the opening in the circuit.
If the fox&hound does not work, first make triple sure the end element connections/splices to the power source are truly powered by paralleling a plain light bulb, not measuring with a meter.

Come back with findings/progress/solution...

Miguel

Yes, TDR.

Or put high AC voltage (like from a neon sign transformer or an electronic air cleaner power supply) low current into the wire and detect the arcing with an AM radio.

Put mains on it and use a live wire detector to find the break.

If you can get it to arc,
then i think a small radio could pin it down quite closely.

Or maybe you could hear the arcing.

Best of luck with it, John

(and post a reply please)