mira sport 9kw shower problems

can someone help me out please my daughter has a mira sport 9 kw shower and yesterday the rcb or mcb whatever you call it cut out, but not only did it cut out, it blew the company fuse and edf energy had to come and put in a new fuse, everything now ok in house, but not with the shower, you set the rcb under the stairs, it is on it own seperate one, and test it seems ok, but the minute you pull the double pole switch chord in the bathroom the rcb cuts out, the shower looks as if it has not been installed long and looks brand new, as my daughter has only had the house since august, i took of the front of the shower and used the wifes ''hair dryer '' thinking that perphas there had been a bit of water ingress into the appliance all nice and dry and looks perfect inside, tried resetting the rcb but every time you pull the double pole chord switch it trips out the rcb any ideas dave

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thanks for all your help and suggestions, it was in fact something my daughter had inherited the problem was in the double pole chord switch in the bathroom, whoever had wired it up in the house earlier (prior to her moving in ) had not tightened up the terminals, thereby the longer you had a shower the more the resistant built up, thereby melting the sheathing on the cable, and tripping the rcd (thank god ) all now well will fit new pull chord and ensure terminals all nice and tight

sounds like a biggy to take the main fuse out,are you sure the cable hasnt been damaged from pullcord to shower somewhere?

unclefewst said:

can someone help me out please my daughter has a mira sport 9 kw shower and yesterday the rcb or mcb whatever you call it cut out, but not only did it cut out, it blew the company fuse and edf energy had to come and put in a new fuse, everything now ok in house, but not with the shower, you set the rcb under the stairs, it is on it own seperate one, and test it seems ok, but the minute you pull the double pole switch chord in the bathroom the rcb cuts out, the shower looks as if it has not been installed long and looks brand new, as my daughter has only had the house since august, i took of the front of the shower and used the wifes ''hair dryer '' thinking that perphas there had been a bit of water ingress into the appliance all nice and dry and looks perfect inside, tried resetting the rcb but every time you pull the double pole chord switch it trips out the rcb any ideas dave

Click to expand...

OK, lets try to clarify a few of the acronyms.

RCD - Residual Current Device - compares the current flowing through the phase and neutral and cuts the power if an imbalance is detected. This has a test button on it and usually protects a number of MCB's (shower, socket circuits etc.) and usually has a 30mA rating.

MCB - Minature Circuit Breaker - short circuit and overload protection. Each circuit is protected by one of these with different ratings (lights - B6, sockets - B32, shower B40)

So now you know what is what, can you tell us what was blowing/tripping? If it is the MCB that trips then you have a short somewhere in the cable after the pull-switch, get someone in to check it out for you and switch off the MCB until remedial action is taken. If the fault managed to blow the main fuse you have some serious issues. I wouldn't be surprised if the cables and pull-switch were damaged during the short.

Davy