In message , Bill Smith writes
Any advice on what's required to provide an electrical supply to a
>greenhouse some 10 metres from a garage where a power supply is available?
First suggestion is to search uk.d-i-y on Google Groups for topics on electricity supply to garage/shed/greenhouse - it's a topic that has been covered quite a few times.
I've added uk.d-i-y to the newsgroup list as there are some knowledge people on there.
Some pertinent questions:
- What load are we talking - I assume heating + maybe propagator, light? so 3 - 3.5 kW? How far is the cable run from the garage supply point to the GH? This is important to size the cable correctly.
- Is the garage supplied from the house consumer unit ('fuse box') or is the supply in the garage the main house supply? If the former how far is the garage from the house and what sort of load would the garage supply have to feed? - this would need to be considered because it might be that the supply cable to the garage would need upgrading.
- How would intend running the cable to the GH - I assume underground?
Ok, general approach would be:
- Start the GH supply from spare way in the consumer unit in the garage. It would need a suitable sized MCB. If there is no CU in the garage, then it might be possible you could run it as a fused spur from the garage socket circuit.
- Run the supply to the GH in SWA (Steel Wire Armoured) cable, buried deep enough to avoid damage when digging the garden. There isn't specified depth - I put mine and the water pipe at about 450mm down.
- Terminate the SWA in the GH - best thing would be to terminate it in a small CU with say a couple of ways. Use a 16A MCB to supply sockets. MK Masterseal are good sockets for use in GH. The main switch for the CU should be an 30mA RCD to protect the whole GH installation.
- Earthing is important here. You can either earth the GH supply via the house earth, or it can be isolated from the house earth and earthed via an earth rod - the latter is what I did.