I'm in the process of refitting my bathroom, and want to double check that I've sorted the right cable size for the electric shower.
The shower unit is a 9.8 kW Mira Escape, which is a higher wattage than the old shower. The existing wiring is 6mm twin and earth fed from a 40A Type B MCB in the 30 mA RCD protected half of a split load consumer unit. It is clipped to the wall downstairs before running through the floor space in the bathroom, up a stud wall cavity and into the loft where it is connected to a double pole isolating switch, then runs down the stud wall cavity to the electric shower. Looking at table 4D2A of the IEE Wiring Regs, it seems that a 6mm T&E cable, clipped direct and/or in a non-insulated wall, 30 degree ambient temperature and not bunched with other cables, is rated for 46A. The Mira instructions recommend a 45A MCB for protection, and the showers current rating is just under 41A.
It seems close, so I just want to double check by asking the experts on here if I've overlooked anything which could alter my cable ratings and mean I need to run a new 10mm T&E supply.
Also, on the same subject, is it acceptable to replace the pull cord double pole isolator in the bathroom with a wall mount double pole isolator located next to the consumer unit (it's out of sight under the stairs then!). I've read that the double pol switch has to be a pull cord in the bathroom, or can be a wall mounted one in an adjacent room. Where I want to fit the switch wouldn't be an adjacent room, but I don't see why that would matter?
Thanks in advance,
Steve
The shower unit is a 9.8 kW Mira Escape, which is a higher wattage than the old shower. The existing wiring is 6mm twin and earth fed from a 40A Type B MCB in the 30 mA RCD protected half of a split load consumer unit. It is clipped to the wall downstairs before running through the floor space in the bathroom, up a stud wall cavity and into the loft where it is connected to a double pole isolating switch, then runs down the stud wall cavity to the electric shower. Looking at table 4D2A of the IEE Wiring Regs, it seems that a 6mm T&E cable, clipped direct and/or in a non-insulated wall, 30 degree ambient temperature and not bunched with other cables, is rated for 46A. The Mira instructions recommend a 45A MCB for protection, and the showers current rating is just under 41A.
It seems close, so I just want to double check by asking the experts on here if I've overlooked anything which could alter my cable ratings and mean I need to run a new 10mm T&E supply.
Also, on the same subject, is it acceptable to replace the pull cord double pole isolator in the bathroom with a wall mount double pole isolator located next to the consumer unit (it's out of sight under the stairs then!). I've read that the double pol switch has to be a pull cord in the bathroom, or can be a wall mounted one in an adjacent room. Where I want to fit the switch wouldn't be an adjacent room, but I don't see why that would matter?
Thanks in advance,
Steve