Hot tub lighting

Hi All
Ive been trawling the forums to try and make a judgement on which regs to follow.
Ive a client with a Wood fired Hot Tub, it has a blower and lights fitted. The manufacturer states the appliances is Class 2.
The hot tub has a internally mounted rccb 30ma, flex and European style plug which will be jointed to a swa cable under the tub.
Reading guidance from the Niceic and the IET I find a difference in opinion so I thought I’d ask you.
Niceic takes the view that Hot tubs are not covered under BS7671 so general wiring REG’s apply. However if fitted next to a swimming pool section 702 applies.
IET takes the view: How could an electrical designer claim as a defence that the risks of electric shock for a hot tub installed outdoors is any less than that of a swimming pool, fountain or paddling pool, as defined in the scope of Section 702?”
So assume section 702 applies.

The hot tub has been placed on a slabbed patio area with two steps up to another patio area. There are ground mounted floor lights within 2 meters of the tub on the steps above the tub level.These floor lights are fed from a selv constant current driver with a max output voltage of 70V DC.

So if section 702 applies these lights would not be suitable looking at 702.55.4
So would you advise applying section 702 or general BS7671 regs?
My problem now is that each light is around £350ea and the ground works have been completed, so to change the lights/wiring would be very costly.
Also the earthing arrangement for the installation is TN-S. Which is ok for the class 2 hot tub?
Any advice appreciated.
Parents
  • I'm thinking of connecting the earth core of the SWA via a separate earth bar in the plant room to this steel work as an earth electrode. I could keep the armour connected to the TN-S system and isolate it via a plastic gland at the shed and use the TT connected 10mm core as the earth. The above reg doesn't specify where the electrode or earth mat is located.

    If I'm reading this right, the SWA would basically be on the TN system, but the 3rd core would be the earthing conductor for the TT'd shed? And the 3rd core would only be separated from the live conductors of the TN system by basic insulation.... so a fault (say impact damage to the buried SWA) could connect TN L to TT PE ... make the TT system live but not necessarily trigger ADS.

       - Andy.

Reply
  • I'm thinking of connecting the earth core of the SWA via a separate earth bar in the plant room to this steel work as an earth electrode. I could keep the armour connected to the TN-S system and isolate it via a plastic gland at the shed and use the TT connected 10mm core as the earth. The above reg doesn't specify where the electrode or earth mat is located.

    If I'm reading this right, the SWA would basically be on the TN system, but the 3rd core would be the earthing conductor for the TT'd shed? And the 3rd core would only be separated from the live conductors of the TN system by basic insulation.... so a fault (say impact damage to the buried SWA) could connect TN L to TT PE ... make the TT system live but not necessarily trigger ADS.

       - Andy.

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