I'm about to have a Hot Tub installed in the garden. Before it arrives, I have to ensure that I have a supply available routed from a 32 Amp breaker on the consumer unit through a 30mA RCD and with 4 metre tail (SWA cable) at the instalation point.
I have experience of wiring lighting, ring mains and the like, having installed my consumer unit and most of my house wiring (after which it was certificated), so I consider myself reasonably "competent" with general matters electrical. However, I have never installed an RCD protected circuit or used SWA cable, so I could do with some hints. I've tried getting an electician to do the work but given up - it's a small job and they want to charge the earth and do it when it's convenient to them!
My current consumer unit has a spare 30A breaker but is obsolete so I can't obtain an integral RCD and will need to install a separate unit. The distance from the consumer unit to the end of a 4 metre tail of SWA will be about 20 metres. The Hot Tub Company only provides limited information on the power load, i.e. the instructions in the second sentence of the first paragraph above. However, it will have a 3 kW heater and four pumps so it probably uses a good part of the 32 Amp load required at start up.
My current thoughts are that I should run 10 metres of 6mm Twin and Earth from the breaker in the consumer unit to the nearest "indoor" location to the proposed location for the Hot Tub, install the RCD at that point and run
6mm three core SWA from the outlet of the RCD (for 10 metres) to the Hot Tub.I did actually get a quotation from an electrician (unfortunately, he wouldn't give me a date) which listed what he was going to do and he included an "earth stake" . I can't see why this would be necessary since the mains power supply at the consumer unit includes an earth.
If anyone has the knowledge / experience to confirm or otherwise my proposal and advise me of anything special that I need to know about using SWA, SWA glands and the connection of SWA to RCDs, etc. I'd be grateful.
Jerry