old mem consumer unit, help plezzzzzz

[m25maintenance]

guys im replacing an electric shower like for like, the old shower was 9.5 kw, but was only on a 32 a mem type 1 321 qeb mcb, i told cliant it should be protected by a 40 amp breaker, trouble is the board is oldish and i dont know what breaker to fit,,,, also no rcd protection on boaed, are there any mem rcbo that will fit that board,tanx

 

[ezzzekiel]

cant be as bad as the 9.5 ive just looked at recently fitted in new extension 2.5mm supply

 

[DoBBY]

is uk nominal voltage 230 now? -used to be 240 onetime

Yeh 230v now, european standards.

 

[DoBBY]

cant be as bad as the 9.5 ive just looked at recently fitted in new extension 2.5mm supply

Are you serious?

 

[DurhamSparky]

230v EU!! as said above... however my property enjoys a nice helping of 244V !! i would measure the supply to see what you actually get! some times you can be suprised..! i once saw a reading of 252v that dropped off in the day to 241....!! hmm interesting

 

[m25maintenance]

i think i will call confused.com

 

[davelerave]

ya if it's up over 240v you can add a kilowatt to the load- best check supply voltage as it could affect mcb/cabling

as you said they're marked on the box 8.5/9.5 for 230/240 that's why i assumed you were mostly still on 240v in the uk


DSO here is allowed 10% tolerance (23volt either side of 230v) -but that would be extreme

 

[D80]

From memory its -6% and +10% thats allowed in the UK.

 

[wattsup]

I've had a 10.5kw shower wired in 10mm, for 10 years...on a 32a rcd breaker...never tripped yet..its only on a 32a cos at the time i had one spare...never got round to changing to 40a, no need to now

 

[davelerave]

hmm 10.5kw is a big shower-you sure it's that big

it should trip over time anyhow -according to the characteristic curve of the mcb

i've been miscalculating slightly anyhow-9.5 at 240v =<40amp and 10.5 at 240v =<44amp

i was a bit confused as the uk nominal voltage is now 230 but appararently it can be 240(and also above or below with tolerances)

 

[pushrod]

guys im replacing an electric shower like for like, the old shower was 9.5 kw, but was only on a 32 a mem type 1 321 qeb mcb, i told cliant it should be protected by a 40 amp breaker, trouble is the board is oldish and i dont know what breaker to fit,,,, also no rcd protection on boaed, are there any mem rcbo that will fit that board,tanx

Have you considered checking if there is any significant earth leakage and if not, protecting the whole board with a separate rcd in the tails.

 

[m25maintenance]

Have you considered checking if there is any significant earth leakage and if not, protecting the whole board with a separate rcd in the tails.

cost is issue

 

[pushrod]

cost is issue

As always unfortunately - just thought the client might stretch a bit more for the added advantage of all circuits being rcd protected

 

[davelerave]

you might just get away with the 6sq on that-it's borderline around the 9kw


down to the install method and length of run really
10sq is usually a safer bet anyway

 

[devlin maguire]

MCH 140R30 £57 new from dunstons

 

[m25maintenance]

tanx 4 all the info lads.