I always wondered what method would keep the cables the coolest. For some reason i thought that burying the cables would make them hotter! They do run vertically from the consumer unit to the ceiling so no problem there.
Masonry makes a fairly decent heatsink pretty high specific heat capacity and fairly thermally conductive (imagine walking on a stone floor), the worst thing is air!, its no so bad when the air is free to move and the cable can be cooled via convection, but where its trapped, like in thermal insulation (rockwool fibre in itself isn't much of a thermal insulation, but the structure traps a lot of air), naturally youd expect thermal insulation to make the cables warm though
(the jacket on your cold feed cistern in the attic is to keep it cool though, not to stop it freezeing in winter
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Maybe my original idea of fitting a 30ma rcd is not a bad idea after all then? Im worried however that the old heaters may cause it to trip and they dont come cheap so it could be a waste of money!
I seriously wouldn't worry about it at the moment
I was thinking maybe i could fit a timer switch so that the shower would only operate during daytime hours when the storage heaters are off? I calculated that the storage heaters and shower alone would draw about 115 Amps which is pushing it since the main supply fuse is only 100A.
Aye, heating loads, and lighting and small power would use up most of the 100A, the saving grace is that the fuse will take 150A long enough to shower (... well long enough for a bloke to shower anyway, if you have teenage daughters in the house the fuse might actually blow!), and the heating loads will be on a separate CU to everything else so that there isn't an overloaded CU to worry about... that said, its not good design practice!
I reckon the cleverest arrangement would be one where the shower dropped out the heating on a bank of contactors for the duration of the shower
My house is all electric so i also have an electric cooker! Im not sure how the electricity company would respond to a blown fuse and whether i would end up with a hefty bill?
They'd probably replace it the first few times, but after that they'd recommend you either reduce your loading or have a tripple phase supply installed (they don't generally install single phase supplies in excess of 100A)
While on the subject of showers am i right in assuming that it is impossible to suffer electrocution while using a wireless shower especially as the pipe to the shower head would be plastic as is the existing pipework in the bathroom?
Those are the ones were the heater unit goes in the airing cupboard, hot water is piped to the bathroom, and control is done by a remote RF unit containing batteries... aye, I'd say they are a bit safer than the normal ones as the electric bit is outside the bathroom, but if your shower is RCD protected and your sup bonding is upto scratch then I don't see that a normal one is unsafe at all
I have a spare fuseway at my split load CU that i could use. It is protected by an 80A 30ma rcd.
Cool, what side is the cooker on out of interest?
Im certain that the longest cable run to the furthest heater is less than 25 metres although i do live in a 3 storey house. I (over)estimated that the longest possible cable length would be no more than 23 metres absolute maximum. I calculated this by measuring the longest possible route from CU to heater.
Sounds ok, the 25m thing was a very rough thing to err on the side of safety, volt drop bites around 28m and Zs at 38m