I want to put in a new circuit (let's take Part P as read) to supply a new split Airconditioning unit in my bedroom, and sockets in the loft.
The Aircon has an indoor unit high on the wall of the room, and an outside unit on a stand on the ground outside. I presume because of the latter that the whole thing needs RCD protection. Its maximum input rating is just under 1 kW, but the instructions say to feed it from a 16A breaker, presumably to allow for motor-start surges.
This is what I'm thinking:
32A /30mA RCBO in main CU, feeding a 4mm² T&E cable that runs up to the loft. Cable length will be about 12m, and at its most insulated it will be in a metal conduit of 15mm internal diameter.
Small CU in the loft with:
16A MCB for the Aircon
16A MCB for the sockets
2.5mm² T&E single to a 13A socket high on the wall of the bedroom below, to plug in the Aircon unit (cable run about 2m, some of which will be in insulation).
2.5mm² T&E ring for three double 13A sockets in the loft.
The loft sockets will only be used for low power devices like aerial amplifiers most of the time, and the occasional electric drill or vaccuum cleaner, so the 16A limit on the sockets will be plenty.
The wiring between the inside/outside Aircon units is specified in the instructions as "1.6mm" which is about 2.01mm², so I'm going to use 2.5mm² Multi-flex: http://www.tlc-direct.co.uk/Products/MF2dot5slash3.html
Does this all sound OK?
The thing I'm a bit iffy about is the small CU having two MCBs but no incoming switch or RCD (I'm thinking of strapping them together on the incoming side with the 4mm²). Would this be seen as a Bad Thing?
Finally, is there a good way to mount a CU in a loft where there aren't any vertical surfaces, or can I just make it up as I go along?
Cheers,
Howard
The Aircon has an indoor unit high on the wall of the room, and an outside unit on a stand on the ground outside. I presume because of the latter that the whole thing needs RCD protection. Its maximum input rating is just under 1 kW, but the instructions say to feed it from a 16A breaker, presumably to allow for motor-start surges.
This is what I'm thinking:
32A /30mA RCBO in main CU, feeding a 4mm² T&E cable that runs up to the loft. Cable length will be about 12m, and at its most insulated it will be in a metal conduit of 15mm internal diameter.
Small CU in the loft with:
16A MCB for the Aircon
16A MCB for the sockets
2.5mm² T&E single to a 13A socket high on the wall of the bedroom below, to plug in the Aircon unit (cable run about 2m, some of which will be in insulation).
2.5mm² T&E ring for three double 13A sockets in the loft.
The loft sockets will only be used for low power devices like aerial amplifiers most of the time, and the occasional electric drill or vaccuum cleaner, so the 16A limit on the sockets will be plenty.
The wiring between the inside/outside Aircon units is specified in the instructions as "1.6mm" which is about 2.01mm², so I'm going to use 2.5mm² Multi-flex: http://www.tlc-direct.co.uk/Products/MF2dot5slash3.html
Does this all sound OK?
The thing I'm a bit iffy about is the small CU having two MCBs but no incoming switch or RCD (I'm thinking of strapping them together on the incoming side with the 4mm²). Would this be seen as a Bad Thing?
Finally, is there a good way to mount a CU in a loft where there aren't any vertical surfaces, or can I just make it up as I go along?
Cheers,
Howard