RCD and bonding for pools/saunas

[Rockingit]

Out on site and somehow all the books have walked out the van! Could someone do me a favour and look in the BGB and tell me if bonding is exempted if RCD is in place, and whether the RCD needs to be 2p or not? Not even sure what there may be to bond yet! Cheers muchly. R.

 

[Richard Burns]

Swimming pools have no exemption from the supplementary bonding requirements. Protective measures of SELV or RCD or Separation(1 item). Should have an earth mat connected to supplementary bonding if PME supply.
Saunas have no exemption from the supplementary bonding requirements and all circuits in the location must be RCD protected.

RCD is as specified in 415.1.1 so no mention of double pole.

 

[FrankUK]

702.411.3.3 Additional protection: Supplementary equipotential bonding

All extraneous-conductive parts in Zones 0,1 & 2 shall be connected by supplementary protective bonding conductors to the protective bonding conductors of exposed-conductive-parts of equipment situated in these zones, in accordance with Reg 415.2

702.410.3.4 - Protective measures against electric shock ( Zones 0 & 1 )

ii) automatic disconnection of supply using an RCD having characteristics specified in 415.1.1

415.1.1 ...... not exceeding 30mA, operating time not exceeding 40ms at residual current 5In

 

[Rockingit]

Thanks chaps! Now have the major headache of trying to sort some bonding!!! May have to make do with a connection back to the DB earth (25/4 SWA) instead as the METs about 100m of serious building work away.

 

[Guitarist]

Yeah, it's a great job we have, just sticking a few wires in...

 

[Engineer54]

Thanks chaps! Now have the major headache of trying to sort some bonding!!! May have to make do with a connection back to the DB earth (25/4 SWA) instead as the METs about 100m of serious building work away.

If the supply at source is PME, the 25mm 4 core SWA installation is will not be sufficient as a bonding conductor!! You have a choice, run a separate bonding conductor back to the MET or install a TT system for the whole swimming pool installation. If TN-S your in luck, depending on the Zs values on a 100m of feeder/supply cable!! lol!!

What's the betting no-one provided a connection to the pools re-bar, or to link out from the re-bar to any metallic steps supports, or d/board supports?? lol!! That in it's own, would have given you more than a half decent Ra!!

 

[Rockingit]

If the supply at source is PME, the 25mm 4 core SWA installation is will not be sufficient as a bonding conductor!! You have a choice, run a separate bonding conductor back to the MET or install a TT system for the whole swimming pool installation. If TN-S your in luck, depending on the Zs values on a 100m of feeder/supply cable!! lol!!

What's the betting no-one provided a connection to the pools re-bar, or to link out from the re-bar to any metallic steps supports, or d/board supports?? lol!! That in it's own, would have given you more than a half decent Ra!!

It's not a pool, it's a 'pro' hot tub being installed at a holiday lets place so there is no re-bar etc etc. Once I'd had a good look around I actually decided that there probably won't be anything needing bonding in the building it's being installed in, and I'm guessing that the unit being installed is all class II and they'll use plastic pipe throughout. Which is just as well, really, as to put (as E54 correctly guessed) PME grade bonding in to that location correctly would just be a nightmare.

My plan is just to check in on Tuesday when the installers for it are there and look it over.

 

[Engineer54]

You may not be out of the woods yet!! lol!! Has the floor slab reinforcement been earthed/bonded, only ask because as the back of my mind somethings telling me that on PME supplied areas, where bare feet are going to be the norm (swimming pools/saunas/spar's etc) such buildings need a bonded floor grid!! I may be wrong Rockingit, so give it a quick check in the books ... lol!!

 

[Rockingit]

You may not be out of the woods yet!! lol!! Has the floor slab reinforcement been earthed/bonded, only ask because as the back of my mind somethings telling me that on PME supplied areas, where bare feet are going to be the norm (swimming pools/saunas/spar's etc) such buildings need a bonded floor grid!! I may be wrong Rockingit, so give it a quick check in the books ... lol!!

415.2.1 - Supplementary bonding shall include.....where practicable, the main metallic reinforced reinforcement of constructional reinforced concrete.

But nothing specific in section 702 that I can see. And thankfully I don't have the above situation to deal with! This is the floor of an old converted cider barn.

 

[Engineer54]

All i can remember off the top of my head, is that PME earthing can't be used in buildings used for housing livestock unless there is an embedded earthed floor grid. I believe there is/was something similar for indoor pool/spa installations or where wet bare feet is to be expected. As i say, i could be wrong here and confusing my self with something else. lol!!

 

[Rockingit]

Nothing in 17th that I can find that suggests that those same conditions for cows in parlours extends to swimming pools etc. Mind you - I've no knowledge of how ugly some of the users may be, so who knows?!