Hot tub wiring

[Rob_the_rich]

Hi Lee, couple more Qs

Are you intending to re-connect the tumble dryer to the new supply? might want to add it in your calcs.  Does the area around the tumble dryer have any extraneous conductive parts which might need bonding?

Are you sure 702 is not relevant? Who did you check it with? I think it relevant.

Looking at the instructions http://www.lay-z-spa.co.uk/shopimages/articles/extra/54112_54113_54123_54129_54148.pdf (is this right? which one is it?) there is a 10mA RCD in the equipment, so either that one, the one in the external socket or the one in the CU could trip. If the CU one trips, would this cause a nuisance? I am thinking fridge/freezers on the kitchen circuit, bearing in mind it could trip when no one is in.

Steptoe has made a good point about exporting PME, you might need to provide your own local earth.

As for being slated for being a short course electrician, you are just going to have to live with that I think. Only thing you can do is carry on learning, every day is a school day.

 

[Lee0316]

Hi Lee, couple more Qs

Are you intending to re-connect the tumble dryer to the new supply? might want to add it in your calcs.  Does the area around the tumble dryer have any extraneous conductive parts which might need bonding?

Are you sure 702 is not relevant? Who did you check it with? I think it relevant.

Looking at the instructions http://www.lay-z-spa.co.uk/shopimages/articles/extra/54112_54113_54123_54129_54148.pdf (is this right? which one is it?) there is a 10mA RCD in the equipment, so either that one, the one in the external socket or the one in the CU could trip. If the CU one trips, would this cause a nuisance? I am thinking fridge/freezers on the kitchen circuit, bearing in mind it could trip when no one is in.

Steptoe has made a good point about exporting PME, you might need to provide your own local earth.

As for being slated for being a short course electrician, you are just going to have to live with that I think. Only thing you can do is carry on learning, every day is a school day.

Thanks Rob, some very good advice there. So to start, I understand all too well that everyday is a school day, that's why I am seeking advice. It's a learning curve.

There is no PME. The spa will be located outside, it will not be in a room, it will be covered by type of wendy house made of fabric. The info you gave said "the spa must be supplied through an isolating transformer or RCD not exceeding 30mA" It will be plugged into an IP rated socket containing an RCD. I will install a DP switch at the feed also.

Let me know what you think

 

[Rob_the_rich]

I think you might want to provide us with more information. As requested. Also, how do you know there is no PME?

701 refers to locations

702 refers to areas around swimming pools and basins

703 refers to rooms containing saunas

702 does not specify whether inside or outside.

Wet people will be in contact with Earth, and may also come into contact with the earth from the CU.

 

[roys]

So just to play devils advocate and just wondering, how do the hire companies that hire out these 2 or 3 kW hot tubs get round the whole earth exporting question. Guess ignorance is bliss !!

In the spring time I know my sister hired one for a week and when I asked her how it was powered she said the guy from the hire company just plugged in an extension to the house. Guessing it was about a 15 meter run, think my sis said it takes 12 hours to heat up but I could be well wrong there. 

Sounds like a similar hot tub to the OP's but one difference is one is temporary and one is permanent, although the hazard would remain the same no matter how long it was plugged in, just the risk would be less.

 

[Rob_the_rich]

I suppose it depends on who is in the dock IF something goes fatally wrong.

As long as Lee follows BS7671 and the Manufacturer's instructions he should be ok, legally.

I note that 702.11 says that "swimming pools within the scope of an equipment standard are outside the scope of these regulations". Apart from it not being clear as to which regulations (702 or bs7671), it only mentions swimming pools, not basins. But I suppose you could argue that lazyspas are subject to their own product standard and therefore not within scope.

The work also comes under Part P in Wales, so needs to be notified.

 

[Sharpend]

So just to play devils advocate and just wondering, how do the hire companies that hire out these 2 or 3 kW hot tubs get round the whole earth exporting question. Guess ignorance is bliss !!

In the spring time I know my sister hired one for a week and when I asked her how it was powered she said the guy from the hire company just plugged in an extension to the house. Guessing it was about a 15 meter run, think my sis said it takes 12 hours to heat up but I could be well wrong there. 

Sounds like a similar hot tub to the OP's but one difference is one is temporary and one is permanent, although the hazard would remain the same no matter how long it was plugged in, just the risk would be less.

Doesn't the fact that it has a plug on it, make it a portable appliance therefore not a permanent fixing, thus temporary? 

 

[roys]

Doesn't the fact that it has a plug on it, make it a portable appliance therefore not a permanent fixing, thus temporary? 

Yes I agree, but remember the OP is saying that his hot tub is on a 13A plug as well, I know he is talking about running a permanent supply to it, but in theory, strangely then it would be better on an extension,

And so we saying that it is OK to export earth if it is temporary, yet the hazard still remains the same if we are on a PME system, albeit risk  (probability of hazard biting us) is less.

As I say just playing devils advocate and thinking out loud.

 

[Rob_the_rich]

the MIs in the product I linked to specifically say not to use an extension lead.

702 (if relevant) does not differentiate between permanent or temporary.

There is a tumble dryer too somewhere, hopefully not in the zones.

MIs also state national wiring rules must be followed and a qualified electrician should be consulted with any questions. And here we are.

 

[steptoe]

Another point,

A landlord I know once told me that his insurance states any item over 15kg does not require PA Testing as it is not deemed to be portable, 

:C

 

[Blue Duck]

Does that mean if I filled a toaster with water it wouldn't require testing??

Back to the paddling pool...

Is it class II ?

 

[Rob_the_rich]

Does that mean if I filled a toaster with water it wouldn't require testing??

it would not require testing after being plugged in, it would be toast

 

[binky]

oh lordy, almost anything on an extension lead is basically legal, however, I wouldn't want to mix water electric and people on that basis

 

[Lee0316]

Lots of good info from you all and I appreciate it.

There is no PME in the area as I have checked with the supplier. As for the spa (not using the words hot tub as it's getting off topic) surely as has been said, this is a plug in device and yes it's going in the garden but this device has been designed for the purpose it is intended for. It could be placed next to the house and just plugged in via an open window straight into any ring or radial for that matter. There wouldn't be an issue exporting an earth then!?

As I said earlier as this is only 2kW it has the same influence as a 2kW oven which the regs say can be plugged into the kitchen ring. So it's not the issue of plugging it in it's the fact that it contains water. Again I refer to it being made to be outside and be filled with water so I'd presume (yes I know) that it should be at least IPX6 (don't know what the ingress of solids would be)

The spa will be housed in a fabric tent with no metallic structures within 3m. Should I extend zone 1 since we live in the UK and it's always p****** it down??

The RCD protected socket outlet which is IP rated for outdoors will be located as per specs for spa. Reading between the lines then, I should install an earth rod and connect it to the spa (even though the manufacturers don't call for such protection).

Ok then, bring on the insults about how I know nothing about being an "electrician" :signthankspin:

 

[steptoe]

I could he wrong, as usual,

But, unless things have changed , it was meant to become a requirement for all TNCS systems 

to be PME

 

[Tony S]

I can check in the “network design guide” for you. But I don’t recall seeing that.

Many new services are PME off old TN-S cables which are now TN-C-S. I did a drawing a while back showing all the various bodge jobs in our LV distribution system, I’ll try and find it.

I blame Miss Sweden for the poor state of the UK LV distribution system  :facepalm:

 

[Andy™]

As I said earlier as this is only 2kW it has the same influence as a 2kW oven which the regs say can be plugged into the kitchen ring.

it does not specifically state it can / cant be plugged in, but there is a note in the annex saying that it should be on its own circuit

 

[Doc Hudson]

Lots of good info from you all and I appreciate it.

There is no PME in the area as I have checked with the supplier. As for the spa (not using the words hot tub as it's getting off topic) surely as has been said, this is a plug in device and yes it's going in the garden but this device has been designed for the purpose it is intended for. It could be placed next to the house and just plugged in via an open window straight into any ring or radial for that matter. There wouldn't be an issue exporting an earth then!?

As I said earlier as this is only 2kW it has the same influence as a 2kW oven which the regs say can be plugged into the kitchen ring. So it's not the issue of plugging it in it's the fact that it contains water. Again I refer to it being made to be outside and be filled with water so I'd presume (yes I know) that it should be at least IPX6 (don't know what the ingress of solids would be)

The spa will be housed in a fabric tent with no metallic structures within 3m. Should I extend zone 1 since we live in the UK and it's always p****** it down??

The RCD protected socket outlet which is IP rated for outdoors will be located as per specs for spa. Reading between the lines then, I should install an earth rod and connect it to the spa (even though the manufacturers don't call for such protection).

Ok then, bring on the insults about how I know nothing about being an "electrician" :signthankspin:

I would suspect the running load characteristics of a 2K oven and a 2K spar heater are actually quite different. i.e. the duration for which either is pulling the full 2k load from the circuit.  Reg 433.1.204 does state you must take account of the distribution of the load around the ring as does appendix 15, which also comments on not supplying immersion heaters or similar loads of a ring circuit.  I personally would tend to think of you spar poll heater being more akin to an immersion heater than an oven. Remember ovens are normally adjusting their temperature so as not to burn your cakes or roast beef. Providing you have done a full assessment of the ring you are connecting onto and its loading then your back is covered. But if something does start overheating and some serious cable replacement is needed at a later date due to the spa running while other existing loads are also running I would make sure you have suitable defence.  While a temporary hired spa may be just plugged in, this may only be for a day or weekend etc. A permanent personally owned spar could be a very different loading issue.

Doc H. 

 

[DavidMartin]

I'm assuming no one has noticed that a Lazy Spa is Class 2

http://www.lay-z-spa.co.uk/product/4/bw54112-2013-lay-z-spa-vegas-hot-tub

 

[leesparkykent]

I'm assuming no one has noticed that a Lazy Spa is Class 2

http://www.lay-z-spa.co.uk/product/4/bw54112-2013-lay-z-spa-vegas-hot-tub

yes I had but gave up on the thread ages ago :Salute

 

[Blue Duck]

I'm assuming no one has noticed that a Lazy Spa is Class 2

http://www.lay-z-spa.co.uk/product/4/bw54112-2013-lay-z-spa-vegas-hot-tub

I was wondering if you'd need an earth rod for your lawnmower if It wasn't class 2 ???