Lay Z Spa Equipotential Bonding Question

[Hussain Ali]

Hi,

I bought a lay z spa, and contrary to what I was expecting, it's potentially not quite plug and play. According to the manual "it is recommended to arrange for a qualified electrician to connect the spa pump to an equipotential bonding terminal using a minimum 2.5mm² solid copper conductor"

I've been reading about equipotential bonding and, at the risk of massively oversimplifying, I understand that they're basically saying it's "recommended" to be connected to the common earth of the house, like at the consumer unit or supply.

My question is this, would it be sufficient to clamp some copper cable to some copper pipe that is already supplementary bonded or (this might be completely daft) connecting to an earth bonding plug like this (https://cpc.farnell.com/coba-europe/hr000009/hr-earth-bonding-plug-uk-yellow/dp/SA02447).

Ideally I'd like to avoid getting a spark in and some permanent modification just for something that's going to be in the garden only occasionally.

Appreciate any replies and all opinions!

 

[JohnW2]

... an earth bonding plug like this (https://cpc.farnell.com/coba-europe/hr000009/hr-earth-bonding-plug-uk-yellow/dp/SA02447).....

What an odd product!

Kind Regards, John

 

[Harry Bloomfield]

What an odd product!

Kind Regards, John

That item is a means to connect an anti static wrist strap for when working on static sensitive electronic components. It just provides a clip on earth stud.

Not even close to to being suitable for a spar bath. Is the bath a fixture or portable item?

 

[gman76]

That product is designed to be used in ESD protected areas to facilitate attaching wrist straps & bench mats etc. They usually have a 1M resistor in series & are completely unsuitable for any other purpose.

Edit: Too slow!

 

[Hussain Ali]

Thanks. So that rules that out. Maybe not using something like that, but would connection to the earth of a socket be an appropriate method at all?

It's an inflatable hot tub, basically a huge over-engineered paddling pool, with pump/heater attached. Like this: https://www.amazon.co.uk/Lay-Z-Spa-BW14294-Tropez-Floating-Inflatable/dp/B01M0QHM8J

 

[EFLImpudence]

I've been reading about equipotential bonding and, at the risk of massively oversimplifying, I understand that they're basically saying it's "recommended" to be connected to the common earth of the house, like at the consumer unit or supply.

Well, it's rather complicated.

My question is this, would it be sufficient to clamp some copper cable to some copper pipe that is already supplementary bonded

If bonding is required and possible, it would.

To what do you plan to connect it at the spa end?

Is this spa supplied by copper pipe or plastic?

 

[Hussain Ali]

When in use the spa isn't supplied. It's a fill once then remove hosepipe sort of thing.

The pump is electrically supplied via a 7m lead with standard 3 pin plug.

There is a terminal on the base of the pump to connect to for bonding.

 

[EFLImpudence]

Have you a link to the product instructions or the model number.

There is a terminal on the base of the pump to connect to for bonding.

What about the heater?


Presumably the pump is earthed.
I do not see what good bonding it (to the house earth) would do.

It more likely needs bonding to the ground. That is not possible without extensive work.

 

[Harry Bloomfield]

When in use the spa isn't supplied. It's a fill once then remove hosepipe sort of thing.

The pump is electrically supplied via a 7m lead with standard 3 pin plug.

There is a terminal on the base of the pump to connect to for bonding.

Mmm, tricky one..

I would suggest it would be wrong to use a solid 2.5mm wire, far too much risk of it snapping - it needs to be a flexible 2.5mm, but I'm stumped by where it needs to be connected or bonded to, so it would ensure it was connected, before before the unit is plugged into the mains socket - ANYONE?

It absolutely MUST always be protected by a circuit protected by an RCD - I cannot emphasize that enough - MUST BE!

The best way to ensure that is by installing a special socket for it, which incorporates an RCD and only allowing it to be used via that RCD socket.

 

[Hussain Ali]

It absolutely MUST always be protected by a circuit protected by an RCD - I cannot emphasize that enough - MUST BE!

Thanks Harry. I should have said, not a standard 3 pin plug, it has a 10mA RCD incorporated. The sockets are all on 30mA RCD as well.

I strongly suspect 99% of people don't bother about the bonding, but I'm that 1% who worry about it!

 

[Harry Bloomfield]

Thanks Harry. I should have said, not a standard 3 pin plug, it has a 10mA RCD incorporated. The sockets are all on 30mA RCD as well.

I strongly suspect 99% of people don't bother about the bonding, but I'm that 1% who worry about it!

I suspect it is just a matter of extra earth bonding, just in case the earth wire in the flex should fail or become disconnected.

 

[Hussain Ali]

Have you a link to the product instructions or the model number.



What about the heater?


Presumably the pump is earthed.
I do not see what good bonding it (to the house earth) would do.

It more likely needs bonding to the ground. That is not possible without extensive work.

Thanks EFLImpudence.

Product manual is here:
https://support.bestwayaftersales.c.../03/BW14294-Lay-Z-Spa_Saint_Tropez_Airjet.pdf

The pump and heater is one combined unit, sorry should have been more specific. It's earthed and has RCD incorporated into the plug.

 

[EFLImpudence]

That looks to be the only touchable metal on the pump -
and presumably it could be on grass/mud -
just seems pointless.
There is nothing to bond (join electrically) it to.

Perhaps you could contact the manufacturer and ask them what it is supposed to achieve.

 

[EFLImpudence]

I suppose if it were installed in a bathroom, then it could be used to bond the CPC(earth wire) to a metal pipe which might be required in such a situation.

Although that could be done at the socket into which it was plugged.

 

[Hussain Ali]

Sounds to me like it's really not necessary in this situation. I will contact the manufacturer to see what they say it's supposedly for.

If I was really concerned, I guess I could just put some flex on it and wire earth only in a plug and shove in the same double socket that I'm plugging in to for power supply. Probably won't bother though.