Shower circuit help

[Barrington1990]

Hey guys , went to a job last night to quote for a new shower install ... After removing the old shower front , I discovered 2 X 2.5mm t&e instead of 1 6mm .. the current shower is 8.5kw and ran into a 40a MCB on RCD side of a split board .. no signs of perished cables or burning anywhere ... Just wandering if ok to go ahead and replace or offer a new circuit in 10mm .. ? .. ps .. don't throw the book at me please haha ..

 

[telectrix]

basically you have 2 x 2.5mm cables in parallel. if installed ref.method C, that gives you a Iz of approx 50A, so with a 8.5kW load (36A) Iz>In>Ib. unconventional, bit can't see a problem, asuming that the load is equally shared between the 2 cables. tin hat ready.

edit: what rating shower is being proposed?

 

[Barrington1990]

basically you have 2 x 2.5mm cables in parallel. if installed ref.method C, that gives you a Iz of approx 50A, so with a 8.5kW load (36A) Iz>In>Ib. unconventional, bit can't see a problem, asuming that the load is equally shared between the 2 cables. tin hat ready.

edit: what rating shower is being proposed?

Shower is 8.5kw .. Triton exite plus ..

Thanks ? I just wanted a second opinion as I've never seen it done like that before ..

 

[westward10]

The cables need to be approximately the same length and you need to verify the cpcs in parallel are satisfactory with regard to carrying the fault current.

 

[telectrix]

and check if cables are buriedin itchy-poo in attic. that would derate the ccc by upto 50%.

 

[littlespark]

You think they utilised an rfc to supply the shower? Why not run 6mm at the time.

id check there’s no sockets on the circuit as well.

is there an isolator before the shower?

very very strange.

 

[DPG]

You'll have to be very sure that the two cables are the same length/route.

 

[Rockingit]

You'll have to be very sure that the two cables are the same length/route.

Simple R1R2 on each, should be the same

 

[Mike Johnson]

I would also crimp them together to prevent future separation in the CU and clearly label them.

 

[Wilko]

If there is an option, I would likely run a new correctly sized cable. This install has questionable ccc due to installation method and cable lengths. And to me it smells like a short cut when it was originally installed. Just my personal view but other than our beloved RFC, any ccc that required 25mm or less should be realised in a single conductor (voltage drop considered separately ).

 

[telectrix]

i had a full roll of 2.5mm on the van. nearest 6.0mm cable was 40 miles away, and the pub was opening in half an hour. no contest. ???. ( and i did give the customer the readings on a beermat).