new 10.5kw shower tripping out

A

alang666

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• 6 Jan 2007

• #1

help!!!

Just installed a 10.5kw shower via 10.5mm2 cable . Main consumer unit is 100A. Have put in a 80A RCD and it has a 40A MCB. Runs ok on cold water so circuit is good. Soon as you turn shower to heat the RCD trips out .

Now I have realised that for a 10.5KW you should put in a 45A MCB but can anyone tell me if this wil prevent the tripping ouit of the RCD or do I have a problem with the new shower?

Help appreciated

 

D

DESL

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• 6 Jan 2007

• #2

Just installed a 10.5kw shower via 10.5mm2 cable

Click to expand...

You did it yourself?

Now I have realised that for a 10.5KW you should put in a 45A MCB but can anyone tell me if this wil prevent the tripping ouit of the RCD

Click to expand...

MCB is for overload and short circuit protection and will work on a 10.5 Kw shower.

RCD is another matter the fact that it is tripping indicates there's a leakage of current to earth and is potentially dangerous - far more than running a 40A MCB at ~ 45A.

do I have a problem with the new shower?

Click to expand...

Possibly but probably not is this a replacement shower or a completely new installation?

This will help in finding out what the fault is.

 

B

breezer

• 6 Jan 2007

• #3

alang666 said:

Just installed a 10.5kw shower via 10.5mm2 cable .

Click to expand...

Now that is clever

if it is the rcd, these are designed to trip when there is a fault to earth, check you have not "nicked" and heater connections when fixing it to the wall

 

S

Steve

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• 6 Jan 2007

• #4

The solenoid that opens the water flow - how much 'lectric does this use? I ask because depending on the shower model, this should be the only thing running in cold mode, and if its below 30mA consumption, it wont trip the RCD if someone's used the wrong neutral busbar . . . .

. . . The heater, however, will trip the RCD it someone's used the wrong neutral busbar . . .

. . . Just a theory, only valid if the solenoid uses less than 30mA.

Breezer, the thing thats clever is the fact he's used 10.5mm² cable

 

B

breezer

• 6 Jan 2007

• #5

Crafty said:

Breezer, the thing thats clever is the fact he's used 10.5mm² cable

Click to expand...

funny, thought that is what i did imply

 

P

ppuch1

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• 6 Jan 2007

• #6

it must be 0.5 mm2 for every 0.5kw

Talking of showers... I changed one recently.
The customer thought he could smell burning, when I went and checked I couldn't smell anything at first and then when I turned the shower on it all became apparent. Quickly switched off and isolated then opened it up to see this ...
http://i122.photobucket.com/albums/o264/ppuch1/CameraPictures042.jpg

 

RF Lighting

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• 6 Jan 2007

• #7

We love pictures

I have seen one similar but it is fairly uncommon for a shower to end up in a condition as bad as that.

BTW if you surround the link to your picture with

rather than the tags the picture will be displayed stright on the forum :wink:

 

P

ppuch1

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• 6 Jan 2007

• #8

you mean like this...

Thanks for the tip.