Outdoor Electrics

17 Jul 2018
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United Kingdom
Just looking for views on an existing outdoor electrics setup and whether any remedial action would be recommended.

Waterproof outdoor socket currently fitted which is spurred off an internal socket in the house. The outdoor socket is running off the downstairs mains circuit. I don't believe there is any issues with this.

Ourdoor shed however is powered, off this outdoor socket, which I think is meant to be a no-no but not entirely sure of the risks around this? It would appear it's been trouble free for a number of years... The shed consists of an LED light and a couple of sockets, one running a fridge freezer permanently.

I don't believe the power from the outdoor socket to the shed is armoured either, but it is ran in conduit under the patio

Is it fine to leave things as is or should some remedial work be undertaken, if so what?
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Is the circuit protected by RCD ?
How is the shed wiring connected to the outside socket ?
So everything is attached to the downstairs RCD in the internal CU

Connected simply by 2.5mm twin and earth
So everything is attached to the downstairs RCD in the internal CU

Connected simply by 2.5mm twin and earth
So the outdoor socket is a spur from the house socket ,which is a ring final socket, and then other sockets,and a light , are spurred from the spur.
Only one spur is allowed from your house socket ,so what you have does not comply with regs ,and the cable could possibly be overloaded before the overcurrent protective device intervenes.
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Thanks Terry.

The outdoor socket used to run the Hot Tub, a Lay Z Spa, but that hasn’t been running since the shed had power.

Would it be a problem in its current setup if I were to start using the Hot Tub again?
Besides the fact that what you have contravenes the regs , your potential issue is you may overload the 2.5mm² cable. You could negate that by fitting a 13 amp fused connection unit in the house that feeds the outside spur etc. That would of course limit the total current to 13amps .
Thanks again Terry. I think I’m following.

The problem I see by doing this though is if I were to run the hot tub it draws 13amps so given the shed electrics are connected into the outdoor socket, which would then be on a 13amp fused connection in the house wouldn’t this just keep tripping? Apologies if I’ve misunderstood.

If I’m right would there be an option to remove the spurred feed for the outdoor socket and shed, and instead have an electrician connect the outdoor socket, and by proxy the shed, into the houses CU?
You could certainly explore the possibility of engaging an electrician to upgrade the supply to everything outside. You are correct in so much as a 13 amp fuse would protect the existing set up from overloading the cable . If your hot tub alone draws 13 Amps ,then you couldn't run much else as well at the same time.
Thanks Terry. Devils advocate here but without the 13amp fused connection being installed in the house in retrospect whats likely going to happen in the current setup if I set the hot tub and run off the outdoor socket?

Should it be the case that the RCD for the downstairs circuit trips? Or is something more dangerous the likely outcome?
Overheating the cable ,with more current running through it than it can safely carry is the risk. RCD ' s do not react to excessive current. Mcbs do. If a cable is carrying more current than its designed to it could go on fire. Your spur cable is only protected by the house socket circuits MCB which is likely to be 32 amp ,but your spur cable can't carry that level of current.
Regs aside, your spur cable can carry 27 amps, i.e. 13 amps for the hot tub leaving 14 amps for your fridge/freezer and LED which won't take anything like that. Personally I would not worry.
Thanks Winston and is that true even in the case where the shed power is spurred off a spurred socket already?
Appreciate the opinions. It does appear different perspectives though.

So what do I do? Lol

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