Waterproof switch beside hot tub Ask questions and find answers to many subjects relating to electrics and electrical work

[t_r_davies]

We have a permanent hot tub with a pergola over it for some protection from the elements, and we would like to install some 12V LED lights around the edge of the pergola for evenings over the winter.

Is it permitted to install an IP66 fused spur on the wall directly beside the tub, into which an IP68 LED driver would be hardwired (through a suitable cable gland) to power the lights?

From my reading of the outdoor zone 0/1/2 rules it appears that this is allowed but looking for some extra input on here if anyone can help please. My usual sparky is in hospital and the other local guy is too busy to come and have a look at the moment.

[ericmark]

The main problem is the equal potential zone. In the house earth bonding means everything is one zone, Outside the earth on the house supply may not be the same voltage as true earth, So there are methods used to ensure all exposed metal work is the same voltage.

The best method is to rely on earth rods with what is called a TT earthing system, in the main we never switch the earth, but with EV charging units we can switch to earth to get around the problems with loss of PEN, this ensures no more than 70 volt between earths, But a hot tube can't have 70 volt that is far too high, so either no earth, or TT system is used.

But we have no idea how your hot tube is wired, so we simply can't answer the question.

[t_r_davies]

The main problem is the equal potential zone. In the house earth bonding means everything is one zone, Outside the earth on the house supply may not be the same voltage as true earth, So there are methods used to ensure all exposed metal work is the same voltage.

The best method is to rely on earth rods with what is called a TT earthing system, in the main we never switch the earth, but with EV charging units we can switch to earth to get around the problems with loss of PEN, this ensures no more than 70 volt between earths, But a hot tube can't have 70 volt that is far too high, so either no earth, or TT system is used.

But we have no idea how your hot tube is wired, so we simply can't answer the question.

Thanks for the quick response @ericmark, much appreciated. The house is on a TN-C-S PME supply (three-phase as it happens but that's not relevant here) and the hot tub is on a dedicated 40A circuit, there's no earth mat or split TT system with local earth installed as the spark said that wasn't needed.

[ericmark]

If the tub is double insulated then yes, no earth required, but it means you can't use anything near the tub which is not also double insulated.