Use existing 1950s metal conduit for rewire

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Hi,

My daughter has just purchased a 1950s ex council house. The wiring doesn't look like its been touched since the 1950s apart from someone adding a couple of extra surface mount sockets.

We plan on having a full re-wire done and new CU. I am going to do all the chasing and running in of cable and an electrician will fit the CU and final testing and certification.

I've chased in a few new socket locations but the light switches are staying in their current locations. The existing wiring is run in round metal conduit, so it may be possible to run the new cable through this conduit without the need for ripping it all out.

Is this a viable option?

Thanks for any advice
 
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Hi,

My daughter has just purchased a 1950s ex council house. The wiring doesn't look like its been touched since the 1950s apart from someone adding a couple of extra surface mount sockets.

We plan on having a full re-wire done and new CU. I am going to do all the chasing and running in of cable and an electrician will fit the CU and final testing and certification.

I've chased in a few new socket locations but the light switches are staying in their current locations. The existing wiring is run in round metal conduit, so it may be possible to run the new cable through this conduit without the need for ripping it all out.

Is this a viable option?

Thanks for any advice

If you can get new cables pulled in - absolutely. Conduit is conduit.
 
Hi,

My daughter has just purchased a 1950s ex council house. The wiring doesn't look like its been touched since the 1950s apart from someone adding a couple of extra surface mount sockets.

We plan on having a full re-wire done and new CU. I am going to do all the chasing and running in of cable and an electrician will fit the CU and final testing and certification.

I've chased in a few new socket locations but the light switches are staying in their current locations. The existing wiring is run in round metal conduit, so it may be possible to run the new cable through this conduit without the need for ripping it all out.

Is this a viable option?

Thanks for any advice

Just be aware that if you want to extend any conduit runs or make alterations, the thread sizes on the 50’s stuff will be imperial and any new stuff will be metric. You can buy adapters should you need to.
 
Hi

The conduit isn't continuous its just been used for the drops where it has been buried in the plaster, i haven't had chance yet to take an old socket off to to look if it connects to the backbox but from where is drops under the floorboards its looks like a metal tube with perhaps rubber at the top. are there any issues with it being metal. i.e. do i have to earth it somehow.
 
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Pulling new cable sinto old conduit works well, provided that care is taken to ensure there is no damage to the cable from sharp metal edges while pulling the cable into the conduit.

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Before you start, it's probably best to check with your electrician (who has to sign it off as being done properly) that (s)he's happy for you to do the parts that you want to do, e.g. the running in of the cable.
 
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The conduit isn't continuous its just been used for the drops where it has been buried in the plaster, i haven't had chance yet to take an old socket off to to look if it connects to the backbox but from where is drops under the floorboards its looks like a metal tube with perhaps rubber at the top. are there any issues with it being metal. i.e. do i have to earth it somehow.

It can and should be earthed by being connected to the back box - which you can probably also reuse if you use 4BA screws (keep the old ones) or retap the threaded lugs to M3.5. The back boxes probably have a 2BA tapping for an earth screw but the screw might have been omitted.

You will need to use twin and earth and modern T&E isn't as flexible as the old multistranded stuff.
 
Just be aware that if you want to extend any conduit runs or make alterations, the thread sizes on the 50’s stuff will be imperial and any new stuff will be metric. You can buy adapters should you need to.

It will be the old, thin grip conduit, rather than the threaded, it might even be oval. It could be reused, but I suspect you might need to find means to connect adequate earth to it..
 
Sometimes the old tube won't be connected to the back box - in the 50s there was a trend to use wooden back boxes.

Sometimes the tube would be connected to a metal back box, but were some back boxes which aren't compatible with modern fittings.

You say the conduit is not continuous, so, as said, T+E will have to be used.

As regards to earthing these bits of conduit, I would say there's no need to if it's buried in the wall and T+E is used - the theory being modern metal capping doesn't need to be earthed, so why should this?

Hopefully someone will correct me if I'm wrong.
 

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