Hot tub wiring

[iceno9]

So i'm about to start a new project to build a decking that will be used to hold a hot tub in the future. My question is, what do i need to keep in mind when doing the job?

I assume the cable whilst needing to be rated for the current must be armoured?
How deep does the cable need to be in soil/garden?
How deep does the cable need to be if under concrete paving flags?
What if i use PVC tubing, does this change anything as its protecting the wire?
Should the PVC tubing have drain holes drilled on the under side?
I assume an isolation switch is necessary for the hot tub and this needs to be minimum 2 meters away from the tub?
I assume it will need its own circuit from the consumer unit OR fuse box?
I guess an RCD will be required at the consumer unit/fuse box?
Is IP54 ok for anything outside (i.e. the isolation switch)
If the isolation switch is mounted under the decking (i.e. you have to remove a hatch to get to it) is this ok? Can it then be less than 2 meters from the tub?
Any other recommendations?

Regards
Matt

 

[ban-all-sheds]

So i'm about to start a new project to build a decking that will be used to hold a hot tub in the future. My question is, what do i need to keep in mind when doing the job?

That you'll need to apply for Building Regulations approval before you start.

And that getting it wrong could kill people, so you need to make absolutely sure that you get it right and test it properly so that you know it's right.

Regarding everything else, this should cover most of it:

• 
  
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm (all subsections)
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcb2
  
  
• http://www.tlc-direct.co.uk/Book/7.13.3.htm
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:swa-gland
  
  
• http://electrical.theiet.org/wiring-matters/16/elect-inst-outdoors.cfm?type=pdf
  
  
• //www.diynot.com/wiki/electrics:part-p
  

Since complying with BS 7671 will be by far and away the easiest way to comply with Part P, I strongly suggest that you get a copy of the Wiring Regulations and study the requirements for outdoor pools etc.

 

[iceno9]

Thanks for the reply - i will have a read (I have an electronics degree - so its not rocket science to me, but then im not normally doing wiring regs).

Regarding the building regulations aproval....what is this for, whats the background behind this?

Thanks

 

[ban-all-sheds]

See the last link in the list above....

 

[flameport]

Regarding the building regulations aproval....what is this for, whats the background behind this?

The law requires that certain works are notified to building control, primarily to ensure they comply with applicable regulations.
It's not an optional item, unless you want to break the law.
Installing a hot tub is notifiable.

As for the rest:
There are no specific depths for the cable, it all depends on exactly where and hot it will be installed. However 450mm depth would be typical for a domestic garden.
PVC tubing changes nothing, and would not protect anything. A spade will easily chop through it.

The tub will require it's own circuit and suitable RCD. The isolating switch(es) must be accessible. Concealing it under a panel does not meet that criteria.
IP54 might be suitable. Or maybe not. Depends on the environment it is installed in.

There are also plenty of other issues to consider, such as the earthing arrangement for the circuit supplying the tub and any other equipment such as lighting etc.

Ultimately, this is not something you should be attempting yourself.

 

[bernardgreen]

So i'm about to start a new project to build a decking that will be used to hold a hot tub in the future. My question is, what do i need to keep in mind when doing the job?

You need to follow the advice already given. Employ a reliable electrician to install the electrics when you get the tub, the supplier should be able to recommend an electrician with the necessary experience.

You could install ducting under the decking into which SWA ( steel wire armoured ) cable can be pulled in by the electrician.

You also need to consider how you will fill and empty the tub. water supply pipe and drain pipes ?