6mm or 10mm??

[punkyb]

Following on from a recent posting of mine, electrician is coming out to replace the isolator with a new 45a shower protection unit with RCD, I raised the question over whether the 6mm t&e cable would be sufficient for the new 9.5kw shower to which he said it would be, now he being a expert who am I to question, but I have seen plenty of posts stating that 10mm should be used,

I have measured the run out and would say (allowing for additional to put a new pull cord switch in) that cable length would be 13m-14m, first 4m pinned to inside of garage wall, then goes through external wall of the house, into bathroom floor pinned to joists, then up inside of stud wall to new cord switch, back down wall again across floor then up inside of other stud wall into back of new shower, are there any issues with the heat disipation of this route with the smaller cable or with the cable itself??

Many thanks,

 

[trey]

I had 6mm on a 10m run to a 9.5kw shower. It also had a join (at a 30A junction box) and ran in insulated stud wall for 2m. It never caught fire, but you could feel the cable get warm. It obviously never worried the previous owner, but after first RCD protecting it I eventually had the whole thing replaced.

 

[ricicle]

6mm is fine for that distance and load as long as it is not in contact with thermal insulation anywhere along it's route or in trunking or grouped with other cables for any significant distance.

 

[punkyb]

trey, ricicle many thanks for your replies, that has put my mind at rest, it will be not be in contact with any thermal insulation, just pinned to joists/studs so looks ok, thats handy had a bit of a shock when I looked at the price of 10mm cable!

 

[trey]

How much was it (the 10mm cable). I just bought 14m of 10mm and 12 of 16mm for £60. Copper seems to be coming down a bit.

 

[DESL]

World Banking crisis has reduced the demand for raw materials so cable prices have dropped but not as much as copper on the world markets.

 

[punkyb]

Trey this is what I found, yours looks like a good deal http://www.wickes.co.uk/Cut/Twin-and-Earth-Cable/invt/156235

 

[Vicario]

It's a bit worrying that the link also suggests 'you might also need a smoke alarm'!

 

[hairyben]

It's a bit worrying that the link also suggests 'you might also need a smoke alarm'!

I thought

Product Description

*6242YH and BS 6004 BASEC approved
*For extra safety please check ratings of appliance prior to connecting flex/cable.
*Suitable for 2 way lighting circuits

was more impressive!

50 amp lighting circuit?!!?

I'd like to see you get it in a plateswitch with a 16mm backbox lol.

 

[Click-Sure]

Yeah, I hate walking into the handle on my lightswitches....

 

[GaryMo]

6242Y for 2-way lighting circuits? Why not - just use plastic switches and brown sleeving on the CPC!

[/joke]