Big question: when the element was laid, did you keep any records (such as photos/drawings) showing exactly where it runs ? And did you keep the accurate resistance from then ?
From the description, it sounds rather like it's the same as the (smaller area) one we put down in my mate's bungalow. The wire is a 2 core resistance wire, with the remote end having the cores joined together - so 120V "lost" along the live core down to the far end, and then the other 120V "lost" on the way back up the neutral core. If there's a short between L&N part way along then the resistance will be low, and it'll take more current. There will be little or no heat produced by the section between the short and the far end.
If you had accurate readings from when it was fitted, and took an accurate reading now, you could work out roughly where the fault is. A thermal camera would pin it down.
I know the kit we used talked about checking and re-checking the resistance during installation and tiling. On their website I found the repair instructions which were basically to splice in a few inches of new cable using a repair kit with a short bit of cable and some crimps.
How to run the heating without blowing the fuse ? Well that depends on what kit you have available to you. In part it depends on what the current resistance is, and what it should be. If the resistance is still high enough, then running the element from a 110V site transformer could do the trick - no thermostat etc, just use a plug with a short length of flex and some terminals so you can just "plug in" the element to the transformer.
If the element is too short for that, then other options might be needed. For example, some creative wiring so you can run (say) a fan heater in series with it might do the job.
However you do it, you will need a way of seeing where the heat stops dead - and a thermal camera is going to be by far the most accurate and easy way to do that. Dampening the floor and seeing how it dries out as suggested above might just work - you'll be looking for when there's a dry line following the element, and before it spreads out to a larger dry area.
From the description, it sounds rather like it's the same as the (smaller area) one we put down in my mate's bungalow. The wire is a 2 core resistance wire, with the remote end having the cores joined together - so 120V "lost" along the live core down to the far end, and then the other 120V "lost" on the way back up the neutral core. If there's a short between L&N part way along then the resistance will be low, and it'll take more current. There will be little or no heat produced by the section between the short and the far end.
If you had accurate readings from when it was fitted, and took an accurate reading now, you could work out roughly where the fault is. A thermal camera would pin it down.
I know the kit we used talked about checking and re-checking the resistance during installation and tiling. On their website I found the repair instructions which were basically to splice in a few inches of new cable using a repair kit with a short bit of cable and some crimps.
How to run the heating without blowing the fuse ? Well that depends on what kit you have available to you. In part it depends on what the current resistance is, and what it should be. If the resistance is still high enough, then running the element from a 110V site transformer could do the trick - no thermostat etc, just use a plug with a short length of flex and some terminals so you can just "plug in" the element to the transformer.
If the element is too short for that, then other options might be needed. For example, some creative wiring so you can run (say) a fan heater in series with it might do the job.
However you do it, you will need a way of seeing where the heat stops dead - and a thermal camera is going to be by far the most accurate and easy way to do that. Dampening the floor and seeing how it dries out as suggested above might just work - you'll be looking for when there's a dry line following the element, and before it spreads out to a larger dry area.
