My garage has a small room attached with a sink. I'd like to fit a hand wash unit above the sink, so I can get hot water. The one I have is similar to this:but is 7.2 kW.
I consider myself competent to fit the water heater (I have an electrical engineering degree, I'm a member of the IEE and a chartered engineer). However, I'm not sure of the IEE regulations on this, in particular where a switch must be placed.
The house has a 3-phase supply, one of which goes to the garage. This is fused at 80A in the house, and goes to an 8-way consumer unit in the garage. Hence there is plenty of power in the garage for this.
I have fitted a 40 A RCBO, with a trip current of 30 mA. (The load current is 32 A @ 230 V, so I thought a 40 A breaker was probably optimal).
Obviously I need to run a cable from the consumer unit to hand wash unit. For this I have 6 mm^2 twin and earth.
But I have two questions:1) Is it normal (or advisable) to put a switch close to the hand wash unit, so it can be isolated without going to the consumer unit? Given the heater will be on its own RCBO I could switch it off at the consumer unit, without affecting anything else. It's only about 10 m away from the consumer unit, but there is a door between the consumer unit and the sink.
2) It if is usual to put a switch near the hand wash unit, where should it be - height, distance from sink etc. Should it be so high up, that it can't be reached from the floor without standing on something?
In some ways, I think it might be safer (and cheaper) to have no switch near the handwash unit at all, but I suspect there should be one.
Can anyone tell me what the latest IEE regulations say on this?