Electrical insurance claim for broken underfloor heating 400v+ neutral loss?

[beaumoni]

I'd appreciate some advice on an insurance dispute: Last year the electricity board sent someone to replace our 3 phase meter. He mis-wired it and popped anything electronic, any lights that were on, and a fair number of white goods. He left it mis-wired for about 15 mins and it didn't trip any house fuses. We never worked out exactly what he did, as his boss turned up to re-wire it, and neither me or the insurance company know exactly what he did. It may have been neutral loss or some other other phase wiring cock up.

I'm now approaching the end of a large insurance claim and one thing the insurer is resisting is the cost of repair to an electric underfloor heating cable that no longer works (the whole floor would need digging up). It was fine before, but now pops the RCD. The cable is two wire only, 2600w and the loop resistance is as per spec but there is a current leak somewhere. It's nothing house side of the cable, and has to be under the tiled floor.

I'm trying to understand the conditions that could have caused the insulation to melt or other possible damage? Any thoughts that can help me go into bat against the insurer are much appreciated.

many thanks

 

[pc1966]

If the heating was on and the wiring was such that you had 400V instead of 230V on the heater (for example L2 and N were swapped over during the accident, with the heater is normally on L1-N) then it would be running at 3 times its rated thermal output (as power in a resistor is proportional to voltage squared) and probably would damage insulation some time before actually burning out the heating element. That could explain the RCD tripping on that circuit.

But it would require a bit more knowledge of the heating element and the type of insulation, etc, to know for sure if x3 heat would cause such damage.