My Shower is causing my RCCB to trip...please help!

[thedude1]

canduit

You got me thinking now. What you say is perfectly sensible, here's why..

Im in a flat but its the top flat with only one other below me, so I have the roof space attic and my own front door etc. I use the loft a lot for storage etc and have put boards down so I can walk around.

Now on 3rd January I was hit by 100+mph winds that removed a good part of the tiles from my back roof. So I was up and down the loft a lot during the repairs checking for leaks etc. Up and down like a brides nighty I was! Its reasonable to guess I have worn through a cable sandwiched between loft baords and joists. That might explain the inconsistency in the fault.

I will go up later and root around and see what I can see.

Now question...if the problem is the cable how do I know that it should be between consumer uint and shower switch as opposed to shower switch and shower? Am I missing something obvious here??

I think I will hold off on the multimeter for now...

Cheers

 

[thedude1]

when I said shabby I just meant the switch was bit dusty, but the cables comming through the roof looked good as new, bright and shiny copper. If it is the cable in must be in the run under the loft boards. Ta

 

[canduit]

Now question...if the problem is the cable how do I know that it should be between consumer uint and shower switch as opposed to shower switch and shower? Am I missing something obvious here??

Cheers

Because you disconnected the cable from the switch to shower and there was still a problem before? I would suggest turn off all power, get yer headtorch on and have a root around in the loft looking for a the shower cable, and inspect every inch of it.

 

[riveralt]

Cables should not be run in such a position that they can be damaged or 'crushed' since this will invariably cause problems with the insulation.
So that is the first thing you must sort out.
Then it is a question of conducting a dead test for continuity between the various legs of the circuit - with neither the consumer unit, shower or pull switch connected to the circuit.
From the Consumer unit to the pull switch.
From the pull switch to the shower.
For both legs on a 6mm2 T&E cable you should expect very low ohm readings across L&N and slightly higher readings between L&E and N&E.
If these readings are low then the next stage is to conduct an dead insulation resistance test @500v dc across LN LE NE for each leg- you should get an extremely high Mega ohn reading.
If the reading is low below- 2Mohm then it will fail the insulation test but in reality for single circuits like this you almost always get extremely high readings otherwise you have a problem with the cable and it will need replacing.
However meters that have insulation resistance testers included are very expensive.
This might the time to call in an electrician who you trust to sort out the issues you are having.

 

[thedude1]

Dudes

Fortunately the cable that runs from consumer unit to shower switch is sound. It isn't ran between the loft boards / joists at all, it is actualy run along nearer the eaves and and then dog legs between two joist runs under the insulation and underneath the joists so no pressure on this cable. Still dont solve my problem though.
Its a pig to see the cable run between shower switch and shower though and I would have to do major moving of things but I think we were only concerned about the run between consumer unit and switch anyway. The run between switch and shower is no more than 2m anyway.

riveralt, if we for a moment just say that it is a problem at the consumer unit end, and the shower and shower switch and cables are fine,.....what are the possibilities?
Cheers

 

[riveralt]

riveralt, if we for a moment just say that it is a problem at the consumer unit end, and the shower and shower switch and cables are fine,.....what are the possibilities?
Cheers

The only way to identify where the problem might be is to conduct a systematic test on the cables - which should identify if or on which leg of the circuit you have the problem.
If the cable continuity is sound and meets the insulation resistance test criteria then you can start looking at the shower, switch and consumer unit MCB and/or RCD.

MCB's at consumer units rarely go wrong - but sometimes the live cable can become loose and cause damage resulting in a short circuit.
Note if you are going to test the tightness of the cables (L/N/E) at the MCB - make sure you have fully isolated the consumer unit before you do so.
Turning the consumer unit off at the main switch will still mean there are live cables inside the unit - so take great care.

 

[thedude1]

riveralt

Dude, I appreciate and admire your mastery of the technicalities man, but I don't have the means to test all this. I'm gonna have to take your advice and a get a 'proper' person in on this.

My Brother knows an electrician, maybe I can 'trust' that dude to sort my issue. I'm not as wealthy as I once was and so I don't pay £££ to fix a simple issue, but this is peeing me off, and the wife is burning my ear.

riveralt, how much for a taxi up to Bonnie Scotland? I pay the £ you fix the problem?

Ha ha only joking

Cheers dude