Electric shower woes

Joined
5 Mar 2014
Messages
28
Reaction score
0
Location
Nottinghamshire
Country
United Kingdom
Hello and what a great forum!!

A few years ago we undertook a complete renovation of our 2 up 2 down semi and also added an extension, doubling the footprint and the bedrooms and as per 'Grand designs' et al my wife announced she was pregnant just as we started the project!!
We hired local trademen and by and large were pleased with the results until it came to the electrician fitting the shower a few weeks after moving back in. we had acomplete rewire and provision for the shower was already in place from 1st fix, a cold water feed from below and real chunky cable from above (scuse my terminology :oops: )
The shower was fitted by the electricians underling (it was a Gainsborough 9.5 sc) and all seemed ok until i found a small piece of plastic in the bath (the shower is situated at one end of the bath)
On closer inspection i could see wire between the backplate of the shower unit and the tiles and so gave him a call and he came round and re-arranged things inside, tipped his hat and bade farewell.
Upon use the shower started to trip the rcd after about 5 mins use. He declined to answer any further contacts so we have been putting up with quick showers for a couple of years until it gave up the ghost last week!
I thought if i buy the same or equivalent shower it should be a straight swap so yesterday took delivery of a Gainsborough 9.5 se and was chuffed all the entry points and fixing points were the same. Turned off power, water and removed cover to expose the insides. 1st thing I noticed was a small plastic label instructing the amount of outer insulation to be removed from the power cable and this had been totally ignored, mit was stripped back about 200mm back into the wall. the tiles had been removed and a holed gouged out of the brickwork behind barely covered by the shower cover. to cut a long story short I have managed to fit the replacement correctly with the right amount of insulation stripped off but I can see down the back between the back plate and the tiles and it still trips the rcd after about 5 mins.
The shower is about a 12m cable run from the consumer unit and the cable is extremely thick and each of the live and neutreal has about 7 x1.5mm solid cores to it, the ground may be slighly less at 1mm x 7 cores. the only info on the fuse is Hager MTN 132 B32.
Any advice will be thankfully and gratefully recieved
cherrs
nat[/code]
 
Sponsored Links
The shower is about a 12m cable run from the consumer unit and the cable is extremely thick and each of the live and neutreal has about 7 x1.5mm solid cores to it, the ground may be slighly less at 1mm x 7 cores.[/code]

Probably 10mm² then. Anything smaller has a solid earth conductor.
 
Sponsored Links
OK. So your 9.5KW shower pulls a little over 40 amps.
That is why the 32amp MCB is tripping. It will tolerate 40 amps for a while, but not for too long, that's why a quick shower is OK but a long one leaves you in a soapy mess.

The simple solution is to have an electrician swop the 32A MCB for a 40amp one.
He may need to make a test or two first, but the 10mm cable is ample for the job.


Next patient please, nurse ;)
 
OK. So your 9.5KW shower pulls a little over 40 amps.
That is why the 32amp MCB is tripping. It will tolerate 40 amps for a while, but not for too long, that's why a quick shower is OK but a long one leaves you in a soapy mess.

The simple solution is to have an electrician swop the 32A MCB for a 40amp one.
He may need to make a test or two first, but the 10mm cable is ample for the job.


Next patient please, nurse ;)
Thank you so much and yes a soapy mess that cant see where he left the towel..hospital written all over it!!

Realistically how much would an electrician charge for replacing it?
 
Swapped the 32a for 40amp and the new shower has worked fine until today when the light on the pull chord for the shower went out and now it doesnt work again!! Any clues anyone?? :(
 
Chances are its burnt out in the switch, switch the power off and pull it forward to see if its burnt up, if so you'll have to cut the cables back to clean copper and replace the isolator
 
if the mcb has been uprated from 32a to 40a does the isolator have to be uprated too?
The isolator should be rated for at least 40A - but it probably always was. Changing the MCB will not have increased the current taken by the shower, although it may have increased the duration of showers (hence current flowing) before the MCB tripped - but I doubt that, in itself, will have damaged the isolator, even if it were rated less than 40A.

Kind Regards, John
 
thanks for the reply..its just that when i opened the isolator and tightened the screws up it worked (well the red light came back on) until i turned the shower on and the red light went out again!! :(
 
thanks for the reply..its just that when i opened the isolator and tightened the screws up it worked (well the red light came back on) until i turned the shower on and the red light went out again!! :(
It certainly sounds rather like poor connections - maybe the ends of the cables have become tarnished due to overheating (itself maybe due to screws previously not being tight enough). If that's the case, and if there is slack in the cable, you may have to cut it back until you find some clean shiny copper.

Kind Regards, John
 
Alternatively if you have no slack to pull through and cut back then consider asking your electrician friend to fit an accessible junction box in the loft, cut back the cable to this and then replace the cut back section with new cable and allow yourself a bit of slack.
Make sure all terminations are securely screwed down fully.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top