UK Rewire using old conduits

[Welsh_sparky_21]

Rewiring a house in a few weeks, the lighting circuit is wired in old conduits. Interested to know if you would re use the conduits or just do new chases for the cables

 

[mattg4321]

Re use the switch drops only. Assume it’s slip conduit?

 

[SparkyChick]

If they are the usual old thin metal ones in the wall, you may struggle to reuse, but if you can do.

I've just completed first fix on a rewire, chose not to and chased... switch heights were quite varied so standardised and also wouldn't have been able to get all the cables down them (I usually do loop in/out at the switch when I rewire).

 

[Welsh_sparky_21]

If they are the usual old thin metal ones in the wall, you may struggle to reuse, but if you can do.

I've just completed first fix on a rewire, chose not to and chased... switch heights were quite varied so standardised and also wouldn't have been able to get all the cables down them (I usually do loop in/out at the switch when I rewire).

That’s the way I normally wire but was thinking this time maybe loop in at light of re using the old conduits

 

[Welsh_sparky_21]

Re use the switch drops only. Assume it’s slip conduit?

Yeah I was thinking of doing that and possibly looping the feeds round the lights, then just the one cable dropping down

 

[telectrix]

that's how i would do it. a good sellingpoint regarding the customer not having as much redecoration as otherwise. and keep the switches at a sensible height, not accessible to 2 year old carpet rats or dwarfs.

 

[Dustydazzler]

You can really only get a couple cables down an old split tube but as others rightly say if you want to avoid mashing up the walls you can 3 plate at the lights and just pop a switch wire down the tube.
Done loads of rewires like this

 

[7029 dave]

You can really only get a couple cables down an old split tube but as others rightly say if you want to avoid mashing up the walls you can 3 plate at the lights and just pop a switch wire down the tube.
Done loads of rewires like this

Or if there is somewhere to house an enclosure which is assessable, do connections in them, Nick Bundy uses them enclosures for his wireless switching, only 1pair at light and switch is the advantage .

 

[Welsh_sparky_21]

You can really only get a couple cables down an old split tube but as others rightly say if you want to avoid mashing up the walls you can 3 plate at the lights and just pop a switch wire down the tube.
Done loads of rewires like this

So would you just cut the conduit above the ceiling and just drop the cable down? Or would you leave it as it is, if it’s connected into a joint box etc

 

[7029 dave]

So would you just cut the conduit above the ceiling and just drop the cable down? Or would you leave it as it is, if it’s connected into a joint box etc

Its a good chance it will be slip tube, threaded conduit was not very practical under floor/ wooden joists etc, thats not say it wont be have seen it too, just be quite a few running couplers about where they had no room to get a turn on.

 

[Welsh_sparky_21]

that's how i would do it. a good sellingpoint regarding the customer not having as much redecoration as otherwise. and keep the switches at a sensible height, not accessible to 2 year old carpet rats or dwarfs.

If doing it this way, does the conduits require to be earthed if you are using T+E cable?

 

[telectrix]

If doing it this way, does the conduits require to be earthed if you are using T+E cable?

No need. similar to the use of metal capping.

 

[telectrix]

No need. similar to the use of metal capping.

 

[cliffed]

No need. similar to the use of metal capping.

Agree but with all the regs we have this still requires no earthing, if not in the designated zone then it does.
Everything else metal is earthed, but not this & potentially could become Live

 

[DPG]

Agree but with all the regs we have this still requires no earthing, if not in the designated zone then it does.
Everything else metal is earthed, but not this & potentially could become Live

If it's a conduit drop to the switch then it will be in a prescribed zone.

 

[Dustydazzler]

Also you are running insulated and sheathed cable in the tube so 'double insulated' for want of a better phrase

If you were pulling singles through the old tube then I would want to see it bonded

 

[ImpededLoop]

If it's a conduit drop to the switch then it will be in a prescribed zone.

And the cables are insulated and sheathed (twin and earth), not singles.

As mentioned previously, there will be a fitting on the conduit at the top of the switch drop (a tee or an elbow) that you can remove with a screwdriver. There used to be rubber bushes available to go over the end of the slip tube, but not sure if these are still being sold.

I'd wire it using a central junction box either under the hallway floor with maintenance free connections or somewhere accessible.

 

[Dustydazzler]

And the cables are insulated and sheathed (twin and earth), not singles.

As mentioned previously, there will be a fitting on the conduit at the top of the switch drop (a tee or an elbow) that you can remove with a screwdriver. There used to be rubber bushes available to go over the end of the slip tube, but not sure if these are still being sold.

I'd wire it using a central junction box either under the hallway floor with maintenance free connections or somewhere accessible.

When we did rewires using the old tube we used to put a big JB in the airing cupboard / loft / broom cupboard

1 cable at the switch , 1 cable at the light was quite nice when it came to 2nd fix