First - I am aware that the work I am describing below is Part P notifiable. I haven't yet decided how to deal with that - for now, I'm just exploring the issues. I would appreciate advice on the following.
I want to provide an electricity supply for a shed I am intending to erect at the bottom of my garden. I have an external 13A socket fed from 30 mA RCD protected ring circuit with 32A MCB at the CU. I want to avoid new cable run from the CU so wish to take a feed from the external socket, if viable. In the new shed, I anticipate installing one or two lights, a power supply for garden tools and maybe a feed for a water pump for a fountain.
The external socket is on an external wall of the house and fed from an internal 13A switched fused spur. When the patio was laid, I had a SWA cable laid below the patio with one end terminating adjacent to the socket and the other end coiled with enough length to reach the shed location. Distance from the power socket to the shed will be max. 20-25 metres. As the socket is fused at 13A, I should be able to load the cable with ~3kW, which will be ample for my purposes. I believe I need 2.5mm cable size. However, I am not sure whether the SWA cable is large enough - it may be only 1.5mm. If not, would it be acceptable practice (short of taking up and relaying patio) to take existing cable to a waterproof JB which I can mount on patio wall (~2 metres) and then take correct cable size from there to the shed?
And once I have the supply to the shed, should I install another CU to distribute as described above?
Any other comments or advice?
I want to provide an electricity supply for a shed I am intending to erect at the bottom of my garden. I have an external 13A socket fed from 30 mA RCD protected ring circuit with 32A MCB at the CU. I want to avoid new cable run from the CU so wish to take a feed from the external socket, if viable. In the new shed, I anticipate installing one or two lights, a power supply for garden tools and maybe a feed for a water pump for a fountain.
The external socket is on an external wall of the house and fed from an internal 13A switched fused spur. When the patio was laid, I had a SWA cable laid below the patio with one end terminating adjacent to the socket and the other end coiled with enough length to reach the shed location. Distance from the power socket to the shed will be max. 20-25 metres. As the socket is fused at 13A, I should be able to load the cable with ~3kW, which will be ample for my purposes. I believe I need 2.5mm cable size. However, I am not sure whether the SWA cable is large enough - it may be only 1.5mm. If not, would it be acceptable practice (short of taking up and relaying patio) to take existing cable to a waterproof JB which I can mount on patio wall (~2 metres) and then take correct cable size from there to the shed?
And once I have the supply to the shed, should I install another CU to distribute as described above?
Any other comments or advice?