Shower cable size

Hi

Yet another question on the subject of shower cable size. Could I run in a parrelled 6 mm cable (the original size cable is 6 mm) to allow me to install a new 10.5 mw shower

any factors to take in to consideration?
ie thermal insulation, grouped with other cables, length of run?

May as well pull in a 10mm (providing the current carrying capacity after de-ratings is sufficient and volt drop in spec.)
Uprating your shower circuit is notifiable under part p.

433.4, 433.4.1, 433.4.2, and 434.4 refer to conductors in parallel also 521.8.1 refers to their routing. 523.8 and Appendix 10 also refers to parallel conductors so the answer is quite complex.

Most say “This regulation does not preclude the use of ring final circuits with or without spur connections.” and you must realise the ring main is a special case.

The first question is “are they of equal length?”. Unless they are then the sums are complex.

Where the heat dissipation differs in one part of a route to another, the current-carrying capacity shall be determined so as to be appropriate for the part of the route having the most adverse conditions. (523.9) which further adds to the equation.

I have in the past used 2 x 120mm² cables instead of one 240mm² cable because of the space available and minimum radius permitted for the cable.

Your cable however is not that large and one wonders why you want to use conductors in parallel?

Appendix 10 has three pages of calculation and diagrams and instructions on just parallel conductors. And I am sure if there is a valid reason then people on here would help. But then you would need to prove those calculations to the LABC unless you are registered.

Are you sure you want to go down that path?

ericmark said:

Your cable however is not that large and one wonders why you want to use conductors in parallel?

Click to expand...

Because he already has a 6mm² and wants to add to it rather than replace it.

Dunno why - you could run a 10.5mw shower on bellwire. Can't imagine the water would get very hot though. Maybe it's a doll's house shower?

Good job it wasn't a capital M

RF Lighting said:

Good job it wasn't a capital M

Click to expand...

.

yea, that would probably turn it from a hot water shower to a hydrogen-plasma gun

Seriously, you do not need a 10.5 shower...for a few more pound you can get a brilliant 8.5 shower, a T80Z Triton..

You can get a Creda Aquawave 8.5 shower, I have one, and the performance is perfectly okay for me, even on a cold frosty December Morning! Try B&Q's - that could solve your problem, as an 8.5 shower draws 37amps, which is just within the limit of a short surface run 6mm cable on a B40 MCB - NOT a rewireable fuse.