Cable for pool heater

[bskipper6]

Hi can anyone give me some info on the cable i would need for my swimming pool? i moved into the house with a pool and needed some electrical work done and the sparky wouldnt connect the pool house because it was connected using twin cable with an earth pole out side, the cable was underground but was not amoured. i have ripped out the old consumer unit and will replace with new.
the house has a new cu with a 100amp main fuse, i got some amoured cable from work one length is 10mm 3 core and another is 16mm 5 core (20mm outside diameter and only using is as 3 core) and was wondering if either would be good enough to run pool heater which is 9kw a pump which 500w and a hot tub which has a 1.5kw heater so about 11kw in total. so i guess its around 46amp? the run on the cable would come from cu in house, through the loft and outside underground length around 35m. i was thinking of using a 63amp mcb from house and in the pool house a 63amp incomer with a 50amp mcb for pool heater and 30amp for hotub which runs off a 13amp socket. i only want some insight into whether cable is man enough and some other advice from qualified sparkies, Im quite competent to run cable out and fit cu in pool house and wire up then get sparky in to check it all then connect to main house. any comments welcome good or bad. many thanks. Ian

 

[dan86]

Hi Ian
Do you own any body armour?

 

[bskipper6]

no why lol

 

[dan86]

by this time tomorrow, once you've read the replies, you're gonna wish you did

 

[Marvo]

Welcome to the forum Bskipper.

I'm understanding from your post that you're not a qualified electrician. There's lots of important considerations with this type of work. Earthing and bonding are critical, it sounds like your poolhouse installation has its own earth rod and the installation will probably require RCD protection as well.


Pools and spa baths are very dangerous installations as electric shocks received in these locations carry a much higher fatality rate. Get a professional electrician and discuss with him the best design and how you can save by doing some of the cable installation yourself but do this before starting the install.

 

[bskipper6]

thought as much but i got to know lol one sparky told me 25mm cable so thats why im asking. as some of the 10mm cable you can buy is rated at 70 odd amps.which is plenty i know length comes into it too though.

 

[ruston]

Take heed of above , as you you may fit stuff that has to be pulled out after a sparky has checked it , this is classed as a special location and has it's own section in the wiring regulations. It's not that you may not be competent , it's just that you may not know. The regs on this are to numerous to be talked through on here.

 

[Marvo]

Cable sizing is straight forward although there's several factors to take into consideration such as load, length and method of installation but the earthing method is equally important and there's many factors that determine the best way to go about this so there's no substitute for a full inspection of the existing installation before coming up with a design.

 

[johnboy6083]

It isn't just how many amps a cable can carry. The able has to be derated for its installation conditions, it's length also determines its size, as does the earth loop impedance of the existing installation.