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I have economy 7 and storage heaters, they were costing a fortune to run and I know they do but seemed excessive (£170 a month electric bill most of which was the economy 7 heating)

This week all the heaters went off, electrician checked the fuses etc all fine so he dismantled the fusebox itself (storage heaters on their own box) and he found the negative lead hanging out, burnt and the flex melted, burn mark suggest it had been arcing a bit as well.

This has been replaced and so has the trip unit but still doesnt work, he came back today and checked it all again no different so went further back and found the timed relay burnt out as well (awaiting EDF to replace this now)

My question is this, he said that the negative cable being loose would overload it and thats why its got so hot and burnt out. To my limited knowledge if this was happening it would be drawing much more current than usual to run the circuit and could this be the reason why my electricity bill has been so expensive?

Apologies for the essay but wanted to pre empt any questions if possible :D


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  • #2
The poor connection between the neutral cable and its terminal would certainly increase the overall resistance of the circuit. You also need to bear in mind that these type of fuses (cartridge probably) have a 'fusing factor' of probably 1.5-2 times the rated current so the circuit could have been drawing almost twice as much as expected without them blowing. The cable was in a mess because it was probably only rated up to the design current (the expected power consumption of the heaters) plus a bit extra.

I know from experience that storage heaters can be very expensive to run but you should be able to calculate how much they should be costing on a monthly/quarterly basis by referring to any manuals supplied with the heaters or by contacting your electricity company for some example figures. Anything approaching £150 per month sounds pretty excessive. Bear in mind that the average yearly bill for most people is about £800-£1,000 I think. This applies whether you only or mostly use electricity for everything or use half and half gas/electricity.

Hope that helps,



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  • #3
many thanks Neil that does help a lot, I know I have the manuals for the heaters somewhere so will dog them out.

I took manual readings last night and gave them to EDF so getting a revised bill through soon, tbh am dreading it, last one was £170 and this one am sure is going to be worse (one month) because the week I was without heating I had to run 2 electric oil filled rads just to keep the place at 12degs (single glazing and no loft lagging so it doesnt retain heat well)


How many and what size are your storage heaters?

As an example, if you had 4 x 2.5kw heaters and your off peak cost was 6p/unit, then it would cost around £126.00 per month + vat to run at this time of year when they are on for 7 hours per night.

Add to this all your other electrical usage + water heating and it can easily get up to £150.00
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