Hot tub install help please

[markymark2406]

Just picked up a hot tub which has a 3kw heater the hot tub will be outside, what I want to do is to take a separate supply from the house distribution board this is a Crabtree starbreaker split load with one side covered by a 63amp 30ma RCCB and there is a spare way for the MCB. The earth arrangement is PME and has been done recently
The idea is to take a length of SWA down the outside wall under a piece of decking and into the garage to a small DB which will then have a light circuit and a supply to the hot tub I guess the cable run is no more that 20metres from internal to garage DB
What I would like to know is what size MCB at the internal DB, what size SWA and should there be a local isolation to the hot tub ?

Thank you

 

[Taylortwocities]

Marky

All that is needed is to apply the standard cable calculations procedures and all of your questions will be answered!

What you are planning is the installation of a new circuit. This is notifiable work.

As you may know, there are two options

1. Use a registered electrician - he/she will know exactly how to calculate the necessary cable size(s)

2. You do it yourself, having first raised a BUILDING NOTICE with your LABC. They will insect your work a various stages. They will expect you to have a suitable level of competence to design, install, and test the installation.
From your basic question, with respect, i would suggest that you do not have the competence to even design this.
I would worry about my family jumping into your electrically-connected hot tub unless you know a whole lot more.

My advice: use option 1.

 

[markymark2406]

i am very confident thank you, it's just info to back up my knowledge what I don't expect is a ramble.
The work I do WILL be inspected and tested and the hot tub won't be commissioned until that has been done

 

[AndyPRK]

Isn't PME a concern with hot tubs?

Do a search for hot tub to find out more!

 

[Adam_151]

Isn't PME a concern with hot tubs?

It can be. I'd expect the designer to consider the risk. In the situation described in the OP. I do not think I would export the PME if it was me.

 

[markymark2406]

Would you put in a TT ?

 

[AndyPRK]

So you would put an earth rod near the hot tub.


It easy to electrocute people with PME and hot tubs. I would get an experienced installer to do it.

 

[flameport]

i am very confident thank you, it's just info to back up my knowledge what I don't expect is a ramble.
The work I do WILL be inspected and tested and the hot tub won't be commissioned until that has been done

Confidence and actually knowing what you are doing are very different things.

If this really will be inspected and tested, you need to discuss with that person exactly what you will be installing before anything else, otherwise there is a very good chance they will arrive, have a quick look and then tell you most/all of it is wrong.

 

[RF Lighting]

So you would put an earth rod near the hot tub.


It easy to electrocute people with PME and hot tubs. I would get an experienced installer to do it.

It's easy to electrocute people with TT and hot tubs due to the voltage gradient in the ground, and bare wet feet etc.

 

[ban-all-sheds]

Just picked up a hot tub which has a 3kw heater the hot tub will be outside

Before you spend any money on providing a supply for it (and BTW - you really do need to use an electrician) I strongly advise doing the calculations for its performance and decide if there is any chance it will ever work well enough for you to want to bother spending any more than you already have.

 

[deadshort]

i am very confident thank you, it's just info to back up my knowledge what I don't expect is a ramble.
The work I do WILL be inspected and tested and the hot tub won't be commissioned until that has been done

removed

DS

 

[securespark]

what I don't expect is a ramble.

TBH, if you post something here, people will pass comment on it. If you don't like those comments, tough!

 

[EFLImpudence]

As you have to notify the Local Authority before you start the work and tell them what you intend to do - and pay them a hefty fee,
it would save you money to instead employ a registered electrician to advise you what he wants doing so that he can then do all the paper work.

You said it WILL be inspected and tested and the hot tub won't be commissioned until that has been done so you can't be shy about talking to electricians - so do it now.

Outside power is not a DIY job.

 

[deadshort]

Gents, sorry my fault, is a 2015 post. Which i was reading and became iritated at the "ramble" comment and replied !

DS

 

[EFLImpudence]

Me too. Bugger.