Shower upgrade

[Al-Glasgow]

I am hoping to go from what I think is 8.5kw(sticker on shower not legible) to a new 9.5kw electric shower.

Typical 3 bed semi, bathroom on first floor, kitchen on ground floor.

my shower supply runs from the bathroom inside gyproc cavity to pull cord isolator, then it crosses joists in the loft where it is clippped approx 400mm, then it runs from the loft through a space in the brickwork to the consumer unit inside kitchen cupboard.

I think the supply cable is 6mm squared, this has yet to be confirmed.

Hager 100a 0.003 a rcd

Hager 32 mcb

My main question is will i need upgrading of 6mm cable, mcb and rcd.

I understand many factors concerning cable routing are possible, hence why I've tried to give accurate info.

regards
Alan

ps. I happen to be a plumber working for a major electrical company, so I hope to get one of the sparks to do the work as a homer.

 

[ban-all-sheds]

My main question is will i need upgrading of 6mm cable, mcb and rcd.

Possibly, yes and no.

Go for a 10.5 - 10.8kW shower, and remove the uncertainty over the cable upgrade.

I happen to be a plumber working for a major electrical company, so I hope to get one of the sparks to do the work as a homer.

Get him to make those decisions then - he's the one whose name will be on the certificate...

 

[GaryMo]

For a start, your 32A MCB isn't rated correctly for your current shower (assuming it's 8.5kW @ 240v) so it'll need changing for your impending larger shower. RCD rating is fine, assuming it was a typo and you actually meant 0.03A (30mA).

Is there any thermal insulation in the loft or in the studded wall which covering the cable?

 

[Al-Glasgow]

Thank you for your information gents, much appreciated.

Can you tell me if simply checking say a plug socket would answer the question if I have 230 or 240vac supply ?.

GaryMo,
You are right in saying it does say 0,03a on the RCD.
Also concerning the insulation, yes there is loft insulation but the cable route is not in contact, the cable is tacked along the joist, then through a brickwork gap which is the outer skin of the building.

regards
Alan

 

[GaryMo]

Forget about the 230/240v comment, a 8.5kW shower consumes more than 32A at 230v or 240v so either way the 32A MCB fitted is undersized for the load.

 

[Al-Glasgow]

Forget about the 230/240v comment, a 8.5kW shower consumes more than 32A at 230v or 240v so either way the 32A MCB fitted is undersized for the load.

I see, thats bloomin barratt homes for you i guess.

GaryMo, Do you think my 6mm squared cable will be adequate, I guess the run is around 5 to 7 meters.

regards
Alan

 

[GaryMo]

You'll require a 45A MCB if available for your consumer unit, if not then a 50A.
6mm clipped direct with no other de-rating factors applied is rated at 47A.
If you manage to source a 45A MCB it will require an accurate assessment of installation conditions by your chosen electrician - too close to call from over here. If a 45A MCB isn't available you'll have to opt for a 50A MCB and an upgrade to 10mm cable.

 

[Al-Glasgow]

Ok GaryMo,
Many thanks for information, looks like I need the 50a with the 10mm cable.

kind regards
Alan

 

[GaryMo]

Ok GaryMo,
Many thanks for information, looks like I need the 50a with the 10mm cable.

kind regards
Alan

10mm cable would be my recommendation.