Sealing off old shower supply

[footprints]

Hi, I have a redundant electric shower, switched from outside the room.
The cable is in the wall above the bath and tiled over, I figured to remove the unit cut off the exposed tails fold back to the sides of the cable and tape up, wrap in plastic and cement / tile over. (should I use a junction box too)
Then remove the switch cover put the live wires into chock strip and cut the load wires back so they cannot touch the strip and tape as in the wall. Then fit a blanking plate.
Does this sound OK as I cannot remove the wiring from the wall and under bathroom floor without a lot of damage / aggro!
The breaker for the shower can be switched off but of course there is always the risk it gets turned on in error.
I plan to get the lounge rewired before I decorate it next and I can get the sparks to pull the connection from the box while he is here, but you know how long it can take to get around to jobs like that!
Thanks for your help.

I now await the wrath of an electrician!

 

[kai]

One important job to do - Shut off the main switch first - Take the Shower feed Phase Core out of its Breaker, and place it into the earth bar in the CU. This is vital for full safety.

 

[sparkwright]

One important job to do - Shut off the main switch first - Take the Shower feed Phase Core out of its Breaker, and place it into the earth bar in the CU. This is vital for full safety.

Where has all this connecting unused cores to earth bars come from?

I can see the benefit for temporary work. And please don't think I'm saying your wrong. I suppose it's a good idea particularly if only one of the conductors (phase) is to be removed.

As for permanent work I've never seen it ANYWHERE. And if I did come across it, I'd probably spend half a day investigating it, only to remove it from earth and to put a connector block on it.

This 'practice' is often recommended here for any unused wiring. I don't want it misleadingly connected to an otherwise decent electrical installation. Why not just put blocks on each end of the cable?

I do quite like the idea in some ways though, the more I think about it.

 

[Taylortwocities]

Take the Shower feed Phase Core out of its Breaker, and place it into the earth bar in the CU.

And certainly you must disconnect the line AND ALSO the neutral conductors at the supply (i.e. consumer unit) end of the circuit. A stray neutral that touches earth will cause the RCD (that should be on that shower circuit) to trip together with anything else also protected by that RCD.

 

[Adam_151]

I've spent time in the past tracing low global insulation resistances on DBs to find its something that has been partially disconnected and earthed. The case that I remember was a cabinet containing gear for some long removed discharge floods. The gear had been disconnected by taking the live to the gear out of the incomming connector block... I don't think It has actually been connected to earth, but was instead resting against the earthed cabinet... however the result would have been the same.... it tested down as the old control gear was between N and E. Fixing it was easy... however as this was on quite a large board, with poor marking up and the cabinets existance was not known (above a suspended ceiling). It took a bit of time to locate the source of the low reading

 

[EFLImpudence]

I would say if you want to connect a disused cable to earth it is better to connect all the conductors to the earth terminal and at the other end connect all conductors together.

 

[sparkwright]

What if you're short of earth terminals though?

Wouldn't want to start moving earth wires about so they are out of sequence.

Are there any rules about connecting disused wires to earth blocks?

 

[EFLImpudence]

You could use a single wire from a connector block if short of terminals. It will be more obvious if all the conductors of the disused cable are together.

As usual, the regulations rarely tell you what to actually do but what to achieve - safety.

 

[footprints]

Thanks guys but I'm more confused than ever now.
As said I will eventually get the sparks to cut it dead when I call him in to sort the lounge, but for now is my plan OK?
And before starting work will it be OK to lick my fingers and use them to test it's off!

 

[ban-all-sheds]

Where has all this connecting unused cores to earth bars come from?

NICEIC, IIRC.

 

[eveares]

Where has all this connecting unused cores to earth bars come from?

I guess the idea is to tie any unused connectors inside the distribution board to the earth bar so they are at the same potential as mains earth; then should any of the unused conductors become live for what ever reason, the MCB's, RCD's, etc... will operate providing the impedance through earth is low enough.

 

[PrenticeBoyofDerry]

I would connect all conductors at each end to a suitable sized connector, then pig tail an earth lead to the earth busbar and ID the set of cables as redundant shower.

 

[bernardgreen]

And before starting work will it be OK to lick my fingers and use them to test it's off!

Yes, but this technique is not advised to test it's ON