EICR Coding for (yet another) Hot Tub installation.

[rytech]

Apologies in advance for yet another Hot Tub TNC-S related thread but I'm just after a few opinions after deliberating for some time on an EICR coding.

EICR at a domestic property was found to have a Hot Tub installed on an outdoor patio which is slate flagstone construction, the hot tub is fed from a split load CU in the property in T&E where it meets an SWA in a roof void then continues outside to a DP rotary isolator adjacent to the hot tub. Supply to the property is TNC-S and hot tub circuit is taken from 30mA side of the split load CU. Due to me being well aware of possible issues caused by potential between the TNC-S provided earth and true earth alongside the possible (albeit rare) scenario of the suppliers PEN conductor being lost I have been deliberating wether this should be classified as code 2 or as code 3 because under normal operation there is no potential danger.

Any opinions appreciated as well as if classified C2 should the fix comprise of a supplementary earth rod at the rotary isolator, or to split at this point replacing the isolator with an RCD loosing the TNC-S earth here and converting to TT.

 

[telectrix]

you'd then have 2 RCDs in series. better if you can ditch the front end RCD and just feed from a non-RCD way. then TT the tub end.

 

[rytech]

Ok thanks for the reply, I take your point re having 2 RCD's inline. My main issue at the minute is correctly coding this observation. I spoke to the ELECSA tech line and they advised C2 but I'm not sure, with a good look through the BGB I can only find a note in the swimming pools and basins bit stating that if a PME is used to supply the pool or basin then a grid or rod should be used in addition with a resistance of 20ohms or less to connect to the protective equipotential bonding, my interpretation of this is that a rod will be required only if there are exposed conductive parts and or an extraneous conductive part which on a hot tub there will be neither of these unless the water in the tub will be classed as an extraneous conductive part due to the heating element being submersed and earthed.

 

[telectrix]

go with elecsa on this one. can't be too careful with special locations. better be too harsh than too lenient.

 

[D Skelton]

C2 all day long fella

 

[rytech]

Thanks for the opinions, I think I will go with a C2 just to be over cautious as there seems too be a lack of clarity on the issue. There's so many posts regarding wiring hot tubs with not much closure on the subject, it seems to vary depending on how the regulations are interpreted, hopefully one of the IET guides similar to the "supply to outbuildings" one will be published soon providing a definitive answer.

Thanks chaps