can i upgrade 9kw electric shower to 10.8kw ( album pics inc

hi guys, my mira sport electric shower has decided to pack up...it is a 9kw shower originally put in approx. 1998 ( when house was built) it has now decided to call it a day...but before I buy another I need to find out if possible if I can increase upto a 10.8kw electric shower (or have to stay with 9kw...I do not want to have to change wiring etc..so I have uploaded some photos of current wiring & fuse box set up and hope it is possible from these for someone to advise if it will be fine to go from 9kw to 10.8kw...the photos are at the following album address under... "shower wiring"..... http://www.diynot.com/network/worcesterman47/albums/

many many thanks in advance [youtube][/youtube]

 

10.8kW Shower is going to require a 50A MCB and possibly 10mm twin and earth cable, your existing cable although not totally sure looks to be 6mm and not really suitable for a 50A device.

On the device pictured 32A mcb shower, you should not be putting anything over 7.6kW on it and I would expect your existing shower at 9kW to trip this device out, so I would now recommend that the MCB is looked at and is confirmed as functioning within it parameters! A 40A MCB is the correct rating for your existing shower.

 

hi, thanks for the reply...my friends son is a qualified electrician and he will be doing the work..i just did not want to buy another shower then find out after that it was not a kind of straight forward job and that it was going to be a problem to fit etc ...although in the 5yrs we have been here using the shower it has never tripped out but I will take on board what you have said and get my friends son to view the set up first then advise me as to the best option, many thanks for your advice

 

It is possible for 6.00mm cable to be protected by a 45A breaker, but 45A breakers are somewhat of rarity for most consumer units, then you would also
have to factor in any de-ratings of the cable which would be assessed by the method it is routed and whether it is contained within trunking/conduit and if run within thermal insulation at any point.
As this will brig down the safe current carrying capacity of the cable.
As it stands for a shower at 10.8kW I would suggest that 10mm cable would be needed.
For your existing cable if I am correct with believing this to be 6.00mm, the a 40A MCB could allow for a shower of around 9.5kW to be fitted.

 

The shower is a fixed load and so cannot overload. Therefore all the protective device needs to afford is fault protection and not overload protection.

 

It should still be designed correctly though and adequate protection for cable be in place. The fact that the existing shower required something like 38A,
a 32A breaker would not be suitable for the load requirements, it could be argued that the breaker may not be activated providing the shower was not used continuously for long periods of time but that does not make it right.

 

I am sure Risteard is referring to:

45A load - 47A cable - 50A mcb (Zs ok, of course, for fault protection).

 

so then in a nutshell its not safe or practicle to just swap shower from 9kw to 10.8kw without changing the cable and safety features then ..many thanks guys

 

Fixed load or not I would recommend that a cable that is only capable of carrying a current of 47A was not protected by a 50A MCB, (which is more than likely the only sized breaker that is suitable for load that can fit your board).

Therefore unless you updated your cable you will be restricted to a 40A device (de-rating factors permitting), which would then mean you could only have a maximum load of about 9.6kW.

 

Thank you again. ..the cable thing is now sorted in my mind..I just needed explaining clearly if I had to change or not (and thanks to you I ynderstand now)..so I will stick with 9kw new shower..then get my friends son to replace/upgrade what is needed in fuse box...much appreciated help/advice once again

 

Surely a more relevant question would be, why are you changing the shower? If you think you are going to get a great improvement in rate of flow I think you will be disappointed - a "power shower" will NOT be the result.

 

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