Replaced shower, and isolation switch. Rcd trips

[Softus]

What does "a bit dodgy" mean, exactly? Was the switch faulty or not?

Yes it was.

OK. What was the fault?

Overnight have decided to replace the suspect cable with a new run.

So you're about to make a third change without diagnosing the original fault.

Is there any reason why i should't simply run the cable through a dry bathroom to the shower from the isolation switch as a temp measure to see if its the shower at fault?

Yes - you haven't diagnosed the fault yet.

...with the view that if the tripping continues must be the new shower, so replace that...

Your logic is flawed.

So i didn't explicitly say the old shower was faulty, my mistake, i assumed the most people would realise someone swapping one item for an identical one, does so for a reason.

Of course people thought it was for a reason. It's just the reason is still a mystery. However, you replaced the switch without having a reason to.

I didn't introduce a fault, i simply removed some others, and made an existing one worse.

You don't yet know whether you removed a cause of tripping and introduced a new, and different, cause of tripping. Until you know what the fault is it's very foolish to claim to know what the problem isn't.

So my logic says, new shower, new switch chances that they faulty is much less likely than then chance the existing cable is faulty.

That's not logic, it's wishful thinking.

I assume that as i had to grapple with the cable to move it about a bit to fit the new shower (same model but moved the location of inputs ) , that any existing insulation problem (a live/neutral to-earth ) in the cable which was causing the old intermittent problem was made worse due to the movement of cable and now have a permanent something to-earth problem within the cable.

Don't assume anything.

 

[iforgot]

I was proved right. the old existing cable is faulty. With a new bit of cable between the isolation switch and shower, everything was fine.

Now just need to get the old cable out of the cavity and feed the new one in...

Any tips or suggestions on doing that to make it a bit easier..??? Its really tight, where its been feed down from the loft, into the cavity. The hole its going down through, is only just larger than the cable, and anything i use to connect the cables together to pull one through using the other to take the strain of the weight is going to be bigger than the hole.

 

[Softus]

I was proved right. the old existing cable is faulty.

So you had a faulty cable, then a faulty shower, then a faulty switch.

BTW you never revealed what the fault was with the switch.

 

[iforgot]

yes shower had simply worn out, one of the heating elements didnt work, isolation switch had heat damage around one of the poles, and when i tested it, even when off was allowing some current across.

Cables still in the wall, going to be a right pig to get it out, and get new cable in place.

So have swapped like for like, shower, isolation switch, and soon cable. As i haven't changed the nature of the circuit or load, is it notifiable work??? I assumed not but cant say i know for sure!

 

[Softus]

As i haven't changed the nature of the circuit or load, is it notifiable work?

No.

I assumed not but cant say i know for sure!

You're doing that assuming thing again.

 

[iforgot]

Well it seams the old cable is in very small space, not enough space to pass a second cable down in!

The cable has been secured to the wall behind the small cavity, so its time to-
*remove the tiles
*cut the pasterboard out
*remove cable
*insert new cable
*put paster back
*re-tile
*refit shower

 

[ban-all-sheds]

Good job you needed a new shower anyway....

 

[iforgot]

oh god yes, if this had been an "upgrade" situation rather than a breakdown,i would be very unhappy right now, at the amount of work required !

 

[ban-all-sheds]

Think how unhappy you'd have been if the shower had been fine, but you'd junked it and bought a new one on the assumption that it was the cause of the original tripping...