Cable size.

[gerry.slater65@]

Hello all,
Is there a general "rule of thumb" for the size of cable needed for an electric shower or is the answer as always "it depends"?
In short can I use 6mm cable (already installed) to supply a 8.5Kw shower.
thanks in advance

Gerry

 

[acat]

Hi Gerry

The way to work it out is divide the demand by the voltage 8500w/230 =36.95A then look at the current carrying capacity of your cable 6mm radial 32A 10mm radial 42A.

I always recommned 10mm that way if the change the shower for a more powerful one it is still ok

Hope that helps

Chris

 

[flukey]

Hello all,
Is there a general "rule of thumb" for the size of cable needed for an electric shower or is the answer as always "it depends"?
In short can I use 6mm cable (already installed) to supply a 8.5Kw shower.
thanks in advance

Gerry

hi gerry,
depends on the length of run but 6mm is normally fine

 

[brs73]

my personal rule of thumb is to always install 10mm
be on the safe side
some one might replace a 8.5kw shower with a 10.5

 

[flukey]

as a rule i always install 10mm
be on the safe side

6mm clipped direct carries 47 amps. seems pretty safe to me

op asked if existing cable is ok, not personal preference for new installs

 

[Guest123]

In answer to your query 6mm wil be fine.

On a new install I only use 10mm now, theres no telling what type of shower the client will come up with sometimes.

 

[gerry.slater65@]

Thanks to you all,very helpful answers as normal!

Cheers Gerry

 

[scotsparky]

Fluckey whats the chances of Gerry clipping a 10mm T&E direct round his bathroom????? Slimm i think more than likely in the wall dont you agree?

 

[flukey]

Fluckey whats the chances of Gerry clipping a 10mm T&E direct round his bathroom????? Slimm i think more than likely in the wall dont you agree?

and wouldnt that be clipped direct then?? without knowing the site it is hard to comment but an 8.5kw shower on 6mm cable is fine for 99% of installs

just read your post again scot, reckon you should read the op again, who mentioned 10mm

 

[scotsparky]

No Flukey clipped direct isnt in a wall read the BRB If its in the wall is refrence method 100 - 103 if tis T&E ans as such ther is derating factors.

As for cable size its irrelevent i dont think Gerry would hav either size "clipped direct" and on show for everyone to see in his bathroom.

 

[flukey]

No Flukey clipped direct isnt in a wall read the BRB If its in the wall is refrence method 100 - 103 if tis T&E ans as such ther is derating factors.

As for cable size its irrelevent i dont think Gerry would hav either size "clipped direct" and on show for everyone to see in his bathroom.

oh dear scot. you need to read the BRB properly. the reference methods you quote are for stud walls and ceilings containing thermal insulation. move along a column
standard construction houses (brick/block) where cables are buried in walls and plastered over are reference method C clipped direct
not sure how you know what sort of walls are in the op as neither am i but i would say its standard construction as he hasnt mentioned insulation
suggest you ask the op first to confirm your suspicions or read up on the BRB, a good page to start would be 264

 

[rickdspark]

think you will find that "clipped direct" includes embedded in plaster etc....... 100-103 only covers hollow/stud/cavities and on plasterboard ceilings

 

[silva.foxx]

oh dear scot. you need to read the BRB properly. the reference methods you quote are for stud walls and ceilings containing thermal insulation. move along a column
standard construction houses (brick/block) where cables are buried in walls and plastered over are reference method C clipped direct
not sure how you know what sort of walls are in the op as neither am i but i would say its standard construction as he hasnt mentioned insulation
suggest you ask the op first to confirm your suspicions or read up on the BRB, a good page to start would be 264

think you will find that "clipped direct" includes embedded in plaster etc....... 100-103 only covers hollow/stud/cavities and on plasterboard ceilings

Agreed. It was stated 3 weeks ago!

 

[flukey]

think you will find that "clipped direct" includes embedded in plaster etc....... 100-103 only covers hollow/stud/cavities and on plasterboard ceilings

thought i had already explained that in depth