Plug & Play hot tub installation

[telectrix]

this bit concerns TNC-S:

Hot Tubs and TN-C-S Supplies The NICEIC Technical Helpline is often asked whether a hot tub installed outdoors may be supplied from a circuit taken from an installation forming part of a TN-C-S system, often referred to as a PME Supply. Neither the Electricity Safety, Quality and Continuity Regulations nor the guidance given in Engineering Recommendation G12/4 – Requirements for the Application of Protective Multiple Earthing to Low Voltage Networks published by the Energy Networks Association places any restrictions in respect of the connection of a hot tub to a PME supply. G12/4 does offer several alternatives in respect of the connection of a swimming pool to a PME supply and it is sometimes suggested, erroneously, that hot tubs should be treated in the same manner as a swimming pool. However, it is clear that hot tubs fall outside of the scope of Section 702 of BS 7671 (see Regulation 702.11). So, unless, as stated previously in this article, a hot tub outdoors is installed within the zones of a swimming pool, only the general rules of that standard are applicable.

 

[Cosy Sparky]

I hope you're prepared to back up such a bold blanket statement...

I can back it up because I am almost the only person who does things correctly, safely, and then applies all the belts and braces - my customers use me because I work on these principles and almost no-one else does.

 

[telectrix]

see my last post. your stance is repudiated by NICEIC. time for some reading methinks.

 

[DPG]

I can back it up because I am almost the only person who does things correctly, safely, and then applies all the belts and braces - my customers use me because I work on these principles and almost no-one else does.

I can back it up because I am almost the only person who does things correctly, safely, and then applies all the belts and braces - my customers use me because I work on these principles and almost no-one else does.

Bit of homework needed.

 

[telectrix]

not to mention that by TT earthing the bugger, you are then relying on the RCD for fault protection unless you can achieve a sub 1 ohm Ra.

 

[Cosy Sparky]

see my last post. your stance is repudiated by NICEIC. time for some reading methinks.

The NICEIC are made up of box ticking morons who are only interested in 5pm each day. They are of little or no use to real life and of no use to the enhancement of the human race.

 

[Cosy Sparky]

not to mention that by TT earthing the bugger, you are then relying on the RCD for fault protection unless you can achieve a sub 1 ohm Ra.

Sub 1 ohm is exactly what I manage to achieve with almost every TT installation - anyone who can't should not be installing TT installations.

 

[westward10]

The mower is 'mobile equipment' and as such should be supplied from a socket suitable for such ie has RCD protection. The hot tub is not mobile & is outside the equipotential zone of the supplying building, so therefore should be treated in exactly the same way as say a remote garage or any other detached building - ie should be provided with its own equipotential zone.

You seem to have very strong opinions but I must point out the term Earthed Equipotential Zone has not been used in BS7671 for a long time.

 

[telectrix]

Sub 1 ohm is exactly what I manage to achieve with almost every TT installation - anyone who can't should not be installing TT installations.

mind your head as you go out the door. close it behind you.

 

[nicebutdim]

Sub 1 ohm is exactly what I manage to achieve with almost every TT installation - anyone who can't should not be installing TT installations.

I'd be very interested to learn how you manage this with almost every TT installation?

 

[pc1966]

I'd be very interested to learn how you manage this with almost every TT installation?

Well this one time at band camp I drive the rod through a water main...

 

[loz2754]

Well now I'm convinced this a total windup on the part of @Cosy Sparky

 

[DPG]

Well now I'm convinced this a total windup on the part of @Cosy Sparky

I think you're right. And I fell for it. Doh.

 

[marcuswareham]

I can back it up because I am almost the only person who does things correctly, safely, and then applies all the belts and braces - my customers use me because I work on these principles and almost no-one else does.

They do if you are detached AND you are a proper electrician.

This is a bit strong and it is not that clear cut there are so many factors to take into account, you can't just say every single outbuilding needs to be TT (what if that outbuilding is a granny annexe constructed in exactly the same way as the house ? , if PME is ok for the house why not the granny annexe outbuilding). I have supplied PME earth to a garage and bonded extraneous conductive parts (I would have preferred to TT it myself but it was impossible to get enough separation distance between a TT rod and buried bonded PME metalwork, in effect rendering the whole point of making it TT pointless (and if anything making it slightly less safe by losing the low impedance earth). An opposite scenario is an insulated timber shed with an office inside it which could kept the PME earth but there are some extraneous conductive parts (water pipe, etc) imagine the run is about 150m and the SWA is already in the ground when you arrive, it would be a pain to get a 10mm in the ground to bond that pipe so TT could be a way to go (iv had a similar situation)

Some electricians might have experienced an unbelievably high number of RCDs failing & never a PEN fault so would avoid TT as much as possible, another electrician might not have come across a single failed RCD (unlikely) but experienced a lot of PEN faults so would avoid PME, everyone has there reasons for doing thing one way or another but they are still proper electricians striving to do things safely (for the most part!)

If this was my house and my hot tub, If possible I would probably make it TT and have a delayed 100ma RCD for fault protection and a 30ma RCD for additional protection, so there are 2 RCDs protecting it (if one should fail) and then I have not got the risks associated with PEN faults,
but that's just me, I don't like TN-C-S very much as an earthing arrangement as a few people on here would probably tell you.

 

[Midwest]

Unusual that a person has been a forum member for nearly a year, but has only started contributing in the last week, Cosy Spark?

 

[telectrix]

and it looks like he's gone back to sleep for another year,

 

[stevethesparks]

Sub 1 ohm is exactly what I manage to achieve with almost every TT installation - anyone who can't should not be installing TT installations.

I think you have contradicted yourself there, "almost every TT install"