Advice On Rewire Of Lighting Circuit

[Master Mech]

I have just had some work carried our to rewire a lighting circuit in my house due to it having no earthing.

The lighting circuit is the original lighting circuit that was installed when the house was built in the 50's which was ran in steel conduit.

We now want to fit metal accessories but obviously require earthing for this to be safe so a rewire of this circuit is required & to be honest has been way overdue for replacement anyway.

Like most people I did not fancy chasing all the walls out to install new cables so asked the electrician if the steel conduit already plastered into the walls could be used saving the need to chase the walls out & redecoration.

He said that would not be an issue after looking over the installation as there would be enough room for the new cabling to be fed down the old conduit which was great news.

When he came to install the new cabling here found that he could not install the twin & earth cabling with the sheath attached as there was not enough room inside the conduit.

His solution was to strip the sheath from the twin & earth cabling and then wrap all the individual wires together in electrical insulation tape.

Removing the sheath created the room required to be able to feed the cables down the existing conduit.

Where the conduit ends in the loft space he left the sheath on the cables & the ran them to a junction box.

I have attached pictures to this post of the junction box in the loft space & the tops of where the conduit for the switch drops end.

The same lighting circuit also covers not only the upstairs bedrooms but the landing, hallway & dining room lighting so cables needed to be ran under the landing floor boards & junction boxes installed.

I have attached pictures to this post of the junction boxes under the landing floorboards.

So my question is are there any issues with how this work has been carried out?

I am probably making a mountain out of a mole hill but I would really appreciate your input.

Many thanks

Adam

 

[terryplumb]

Your pics are not showing Adam.

 

[Master Mech]

Your pics are not showing Adam.

Sorry, I have added them to the post now. Can you see them?

 

[terryplumb]

Sorry, I have added them to the post now. Can you see them?

Yes ,but I can't see clearly through my tears !!

 

[Master Mech]

Yes ,but I can't see clearly through my tears !!

Oh god its that bad

What are the key things that are wrong?

 

[terryplumb]

It's not particularly dangerous ,just hard on the eyes. I assume some junction boxes are going to be under floorboards ,and if so would be deemed not accessable. So they must be in maintenance free junction boxes to be compliant. It appears to me that some are not, although the electrician has made efforts to try to comply with the spirit of the regulations by adding cable ties to provide strain relief.
Although so many junction boxes are generally frowned upon ,there is no regulation that forbids them.
Taken into account your reluctance to have walls chased out ,and preferance for the conduit to be used ,the installer has probably had to work his way around this.

 

[AndyPRK]

It looks fine to me.

Maintenance free junctions under floor boards.

 

[RF Lighting]

Taped up singles inside unearthed steel conduit is certainly not compliant with the regulations, nor are those joints flapping about in free air.


As the lighting has been rewired using the junction box method I’m unsure why the wiring couldn’t have been run in properly.

 

[endecotp]

I have just had some work carried our to rewire a lighting circuit in my house due to it having no earthing.

The lighting circuit is the original lighting circuit that was installed when the house was built in the 50's which was ran in steel conduit.

But in that case, the steel conduit IS the earth for the circuit.

Was the conduit tested and found inadequate in some way?

 

[Master Mech]

It's not particularly dangerous ,just hard on the eyes. I assume some junction boxes are going to be under floorboards ,and if so would be deemed not accessable. So they must be in maintenance free junction boxes to be compliant. It appears to me that some are not, although the electrician has made efforts to try to comply with the spirit of the regulations by adding cable ties to provide strain relief.
Although so many junction boxes are generally frowned upon ,there is no regulation that forbids them.
Taken into account your reluctance to have walls chased out ,and preferance for the conduit to be used ,the installer has probably had to work his way around this.

Thanks for your reply, so the junction boxes are none compliant as they are not maintenance free?

I agree, I did push for the existing conduit to be used but if this was not possible then I did say other options were on the table but he did not give me any other options.

Taped up singles inside unearthed steel conduit is certainly not compliant with the regulations, nor are those joints flapping about in free air.

As the lighting has been rewired using the junction box method I’m unsure why the wiring couldn’t have been run in properly.

Thank you for the information, other than converting to a wireless system like Quinetic to get round the conduit issue & not chase the walls out would the use of conduit cable have been an option to keep the work compliant?

I presume the junction boxes should be secured to the joists?

I presume when you say "I’m unsure why the wiring couldn’t have been run in properly" that the cables would be ran sheathed in the conduit?

But in that case, the steel conduit IS the earth for the circuit.

Was the conduit tested and found inadequate in some way?

The conduit was not earthed in any way, apparently from what I have been told in the 50's is was very common place that lighting circuits had no earthing.

Also metal accessories in domestic installations were virtually non existent unlike today so shock risk at the switches was low.

The conduit did not connect to the back boxes in the wall so there was also no way to connect an earth to the light switch without running an additional wire for earthing.

This is what the electrician told me anyway.

 

[AndyPRK]

Did the conduit end at the top of the wall above the switch before rewire ?

or did it used to go over to the light ? and therefore its been cut off ?

 

[Master Mech]

Did the conduit end at the top of the wall above the switch before rewire ?

or did it used to go over to the light ? and therefore its been cut off ?

It had conduit all the way to the light, the conduit was removed/cut off

 

[davelx]

AFAIK, that old split tube conduit was never intended to act as a CPC and was never connected back to the MET. In addition, the joints were not of a type where continuity could be ensured.

 

[sparkwright]

I suspect where he has attempted to get two twin and earth cables down one tube, he could have in fact used a 3 core and earth cable, and altered his wiring at the junction box accordingly.

He shouldn't have done what he did, the conduit should be earthed if it has single insulated wires in it, and the use of tape round the top of the conduit is utter rubbish.

Show us what's inside the switch where he has tried to get the two twin and earths down, and we may be able to think of something better.

 

[Master Mech]

I suspect where he has attempted to get two twin and earth cables down one tube, he could have in fact used a 3 core and earth cable, and altered his wiring at the junction box accordingly.

He shouldn't have done what he did, the conduit should be earthed if it has single insulated wires in it, and the use of tape round the top of the conduit is utter rubbish.

Show us what's inside the switch where he has tried to get the two twin and earths down, and we may be able to think of something better.

Here is a picture of behind one of the light switches that is fed by the cable drop that has the three core with a twin & earth cable fed down it.

You can see the three core cable going through the rear of the back box to the two gang light switch on the other side of the wall.

The light switch on the other side of the wall is a 2 gang switch.