Oustide sockets and a new hot tub

[yellowvanman]

Was just arranging to install a 2g IP socket for a customer tomorrow and now he tells me its for a hot tub!

Apparently hot tub is supplied with a 13A plug! But still trying to get some details on that!

If this is correct do I just install the sockets and not consider what ever he wants to plug into them or should I do more investigations?

Supply is TNC-S (probably)

 

[trev]

Apparently hot tub is supplied with a 13A plug! But still trying to get some details on that!
Supply is TNC-S (probably)

I think I'd hold off on any decision until those 2 words were no longer there.

 

[VoltzElectrical]

Surely, if hot tub is a fixed appliance, that comes pre-wired on a 13 amp plug top, then just install suitably IP rated outdoor socket that meets the current and over current demands as well as meeting the requirements for extra protection then all is well?

 

[VoltzElectrical]

Also, what Tel said!

 

[trev]

Also, what Tel said!

Did he comment?

 

[Barry White]

Seen a blow up hot tub on a 13a socket it came pre fitted with 15 foot of flex and an rcd plug top they take ages to heat up and are available at argos

Buy Canadian Spa Company Grand Rapids Inflatable Spa at Argos.co.uk - Your Online Shop for Hot tubs and spas.

The one I saw was at a barbecue and run off an extension in a IP rated polythene bag

 

[Buckfast]

A few questions which require confirmation,
1)Is supply PME
2)Is Hot tub Class 2 or Class 1
3)Where is hot tub to be sited in relation to general earth mass of earth etc.
4)What are manufacturers recommendations.

Am installing wiring to one myself in very near future and trying to obtain information from suppliers impossible ?. The only information so far is 32A Supply and the house supply is PME. Will wire this as TT with DP 30mA rcd protection and a 25 mtr * 3mm * 25mm earth tape in same trench as sub main. Hot tub 20 metres down garden.

 

[sparksburnout]

Right I'm a bit confused here, not usually difficult. Are we to make a distinction between a proper hot tub that needs its own dedicated supply and is subject to special locations regs, and the blow up types that come with a 13A RCD plug fitted? In the absence of manufacturers detailed installation instructions are we supposed to assume that because it has a plug fitted and the user can presumably plug it into any existing outside socket that it is not subject to section 702? I can't see the difference myself, other than the blow up ones have no metallic parts so there is no possibility of any difference in earth potential or loss of neutral etc

 

[Pete999]

Was just arranging to install a 2g IP socket for a customer tomorrow and now he tells me its for a hot tub!

Apparently hot tub is supplied with a 13A plug! But still trying to get some details on that!

If this is correct do I just install the sockets and not consider what ever he wants to plug into them or should I do more investigations?

Supply is TNC-S (probably)

What Tel said, soooorry what Trev said lol

 

[Engineer54]

As Buckfast has found out himself, there is a bit more involved with an installation of a Hot Tub or Spa than just plugging into a suitable outlet.

 

[sparksburnout]

As Buckfast has found out himself, there is a bit more involved with an installation of a Hot Tub or Spa than just plugging into a suitable outlet.

exactly-so why do these inflatable ones come with a 13A plug on them?

 

[Engineer54]

exactly-so why do these inflatable ones come with a 13A plug on them?

Pass, never seen them to be honest!! Don't sound too clever though do they!! ...lol!!

EDIT... Just had a look at the link to the ARGOS site. Seems that the heater and air pump is contained in a separate module. All looks very cheap and nasty, as you would expect for just 500 notes when the real thing is more like 5000 Quid!! lol Looked at another unit that they are calling plug and play with a 13A plug top, ....all i can say, is that with a 2 KW heater (to heat up almost 900 litres of water lol!!) and a 4 HP air blower motor they won't be able to run both at the same time, which for an almost 5K Spa isn't really acceptable...


I'd want to see some manufacturers written assurances that other UK safety wiring/installation methods are not applicable to these so called plug and play hot tubs/spa's....

 

[sparksburnout]

Pass, never seen them to be honest!! Don't sound too clever though do they!! ...lol!!

No that's what I thought! I got asked to look at one and decided not to bother. It came with an RCD type 13A plug and upon further investigation had no earth, so obviously class 2, but it just seemed like a bit of a pile of ---- to me. No idea where it came from as customer had bought it off Ebay.........

 

[Spoon]

760 Liters of water. 2kW heater. Only takes 8.85 hours to warm the water from 10 deg C to 30 deg C....

 

[sparksburnout]

I'm not saying they are OK, cos they look rubbish to me, but the time taken to warm them up is not really an issue cos you have to keep them on all the time apparently. BUT the issue still remains, are we to treat ANY of these things as a special location, or are they (the blow up ones) class 2 and somehow exempt?

 

[yellowvanman]

Ok, just to keep everyone informed:

House supply is PME and hot tub supply needs to be 32A.

Spoke to suppliers and they say use 6mm 3core 32A/30mA protection, they didn't know anything about earthing systems.

Spoke to Elecsa technical support and they say treat it as a swimming pool (Section 702) and recommend to TT the supply from the Isolator.

Trouble I have now is that this is on a terraced house, hot tub is being placed directly beside the back door. Door is in the middle of the house and on the other side of the door is an external oil fired boiler which is obviously fed from the house and PME earthed/bonded.

Technical support reckon that if the boiler is out of reach of anyone in the hot tub that would be OK - different earthing systems. Just got to find a place for the isolator in zone 2, or it looks like I'm allowed to position an isolator 1.25m from zone 0 if zone 2 is not practicable (702.53)

 

[VoltzElectrical]

Did he comment?

Sorry, meant you Trev, you legend, I love you xxxxx:santa_cheesy:

 

[sparksburnout]

If its so close to the house is there really likely to be a significant PD between the 2 earthing systems??? As an off the wall late at nights comment what about putting a rod down next to the tub and connecting it to the MET?? Are Elecsa only worried about differing earth potentials?

 

[Buckfast]

This thread can open a large can of worms ?. PME used for external supplies can cause problems if the neutral supply conductor becomes open circuit as all cpc conductors could rise to mains potential and supplied equipment is outside equipotential bonding zone. Some argue this is very unlikely to happen, but i would disagree with this and locality and supply arrangements need to be looked at. IE are supply cables from overhead network etc. Will DNO accept PME supplied to hot tub. Would connect this as TT and try to make sure boiler is at least 2 metres from hot tub (Extended arms reach). Potential difference between 2 earthing systems depends on locality of last DNO earth spike. Could be 20 feet away or could be 1/4 of a mile away?. If you do decide to tie PME down with earth spike make sure earth rod installation has very low impedance to be able to withstand fault currents. (Not a path i would take for hot tub installation).

 

[Engineer54]

Some argue this is very unlikely to happen, but i would disagree with this and locality and supply arrangements need to be looked at. IE are supply cables from overhead network etc.

Rare enough that the vast majority of electricians will never see this happen throughout their working life!! If the PME supply is from an overhead DNO supply, then this will be a ''TRUE'' PME installation with N-E connections at every third post. The more N-E connections there are on a PME distribution supply cable the less effect a broken neutral will have.

But i will agree with you that in most cases where hot tubs and the like are sitting on bare ground, concrete or other potentially conductive material, i too would TT the installation, but not with one of those worthless short thin twigs you lot in the UK call an earth rod!! lol!!