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.

Here are some pictures 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.

Here are some pictures 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

 

[Master Mech]

Well for starters 1mm t&e should have been used, also why 2 cables down could of used 1mm 3 core and earth.

The drop that has the three core with the twin & earth cable feeds two switches. A 2 gang switch & 1 gang switch.

When the house was built they decided to use one drop for both rooms.

The only insulation the CPC's have is the electrical tape that is holding all the wires together.

 

[Pretty Mouth]

It seems to me that the problems with this install are a result of the spark trying to keep the OP happy, by avoiding damage to the decor. Had he been able to cut in chases and new boxes, there would have been no need for the junctions in the building voids, or for stripping the sheath from the T+E.

 

[7029 dave]

The drop that has the three core with the twin & earth cable feeds two switches. A 2 gang switch & 1 gang switch.

When the house was built they decided to use one drop for both rooms.

The only insulation the CPC's have is the electrical tape that is holding all the wires together.

The drop that has the three core with the twin & earth cable feeds two switches. A 2 gang switch & 1 gang switch.

When the house was built they decided to use one drop for both rooms.

The only insulation the CPC's have is the electrical tape that is holding all the wires together.

Okay understand that, 1.5mm cable was a bad choice, 1mm cable's might have gone down together with a bit of lubricate such as fairy liquid thats what I have used, failing that chase out the other switch drop, or surface mini trunking.

 

[Dustydazzler]

It seems to me that the problems with this install are a result of the spark trying to keep the OP happy, by avoiding damage to the decor. Had he been able to cut in chases and new boxes, there would have been no need for the junctions in the building voids, or for stripping the sheath from the T+E.

quentic switches would have been the best option

 

[westward10]

6181Y.

 

[7029 dave]

quentic switches would have been the best option

Forgot about them, see new products old sweats like me forget.

 

[Pretty Mouth]

quentic switches would have been the best option

I think the OP had metal accessories in mind. Do quinetic do modules to fit? Would be a good workaround if so

 

[Vortigern]

I would recommend quinetic in that situation but the cost can be offputting.

 

[Vortigern]

6181Y.

don't think you could have got all those down there though, same situation as a three core and earth with two core and earth.

 

[westward10]

don't think you could have got all those down there though, same situation as a three core and earth with two core and earth.

They would fly down?

 

[Master Mech]

Okay understand that, 1.5mm cable was a bad choice, 1mm cable's might have gone down together with a bit of lubricate such as fairy liquid thats what I have used, failing that chase out the other switch drop, or surface mini trunking.

Apologies if I am getting the wrong end of the stick but when you say 1.5mm cable was a bad choice you are saying that 1.5mm2 cable was used?

I can 100% confirm that all the cables used were 1.0mm2 both the three core & the twin & earth.

What seems to have happened back in the 50's when the conduit was installed they had the fantastic idea to flatten/crush the conduit a little that was plastered into the wall so it is more oval than round.

I can only guess but it seems they did this to avoid having to chase the walls out as much.

Even when using 1.0mm2 cable there was no way a three core with twin & earth way going to fit down that conduit with the sheath. He did try with fairy liquid as he asked me for my help to try & pull them through with him.

 

[Intoelectrics]

Personally I would have done things differently, my main concern would be at the entry to the split metal conduit. But I'm not going to jump on the electrician who did this work when we only have one side of the story.
No offense to the OP but we are not privy to what you agreed, cost, limitations, timeframes... It only appears to me that the electrician was trying to save you the headache of redecorating. Maybe there were alternative solutions to overcome this, difficult to say without actually surveying the job ourselves.

To the OP,
have you invited the electrician back to comment/fix any of the things you have pointed out to us?

 

[Intoelectrics]

Even when using 1.0mm2 cable there was no way a three core with twin & earth way going to fit down that conduit with the sheath. He did try with fairy liquid as he asked me for my help to try & pull them through with him.

So at this point did the electrician not suggest an alternative? Since you were witness to the fact that the cables could not be pulled down the conduit, you knew that there was a problem?

 

[Master Mech]

Personally I would have done things differently, my main concern would be at the entry to the split metal conduit. But I'm not going to jump on the electrician who did this work when we only have one side of the story.
No offense to the OP but we are not privy to what you agreed, cost, limitations, timeframes... It only appears to me that the electrician was trying to save you the headache of redecorating. Maybe there were alternative solutions to overcome this, difficult to say without actually surveying the job ourselves.

To the OP,
have you invited the electrician back to comment/fix any of the things you have pointed out to us?

I have him coming back to change the 32 amp MCB on the radial he fitted for a 20 amp MCB.

Like I said in another post when I brought up the above issue he was not a happy chappy so I would imagine it will be the same for the issues discussed in this thread.

I will talk to him about the issues people have brought to my attention in this thread which was the whole point of me creating this thread.

I am an automotive tech & when I looked over the work I saw a few things I was not happy with but this is not my industry so I have not clue if this work was acceptable or not so thought I would ask here to get advice from the people that do before approaching him.

 

[telectrix]

my first thought would ave been to install just 4.0mm single earth cables assuming that the existing twin cable was OK for continued use.

 

[Master Mech]

So at this point did the electrician not suggest an alternative? Since you were witness to the fact that the cables could not be pulled down the conduit, you knew that there was a problem?

Well he had a good think up in the loft & he came up with the solution we have now, the stripped cables.

I thought this was not "correct" so to speak but as I have said this is not my field so I had no way of knowing if this was acceptable or not so I was not in the position to make the call if there was a problem or not at the time.

Hence the creation of this thread, I am not trying to throw the guy under the bus I just wanted other peoples opinions on the work to see if my concerns had any merit.

 

[7029 dave]

Apologies if I am getting the wrong end of the stick but when you say 1.5mm cable was a bad choice you are saying that 1.5mm2 cable was used?

I can 100% confirm that all the cables used were 1.0mm2 both the three core & the twin & earth.

What seems to have happened back in the 50's when the conduit was installed they had the fantastic idea to flatten/crush the conduit a little that was plastered into the wall so it is more oval than round.

I can only guess but it seems they did this to avoid having to chase the walls out as much.

Even when using 1.0mm2 cable there was no way a three core with twin & earth way going to fit down that conduit with the sheath. He did try with fairy liquid as he asked me for my help to try & pull them through with him.

OK looking at the pictures the conductors/insulation do look bigger than 1mm2, but you was there not me.

 

[Master Mech]

OK looking at the pictures the conductors/insulation do look bigger than 1mm2, but you was there not me.

When I get home later I will have a close look at the cables emerging from the conduit but I am very confident they are 1.0mm2

I will let you know.

 

[Midwest]

If I recall, there were/are rubber bushes available for this situation in a rewire. Not that this helps with the amount of t&e down the split conduit.

Could the switch drop t&e cables be replaced with a suitable multi core flexible cable?

 

[Pete999]

It looks a bit rushed / rough and there are undoubtedly bits that could and should have been done differently.

However I'd be struggling to justify paying someone else to rip it out and re-do it. I think that is a reasonable threshold for the difference between a bit rough and downright dangerous.

"A bit rough" is the understatement of the year

 

[7029 dave]

If you look how the cables are positioned before entry of the conduit, no way will go down, they need to be flat both overlapped and run in to the contour of the flat end of the conduit with a little lubricate 1mm2 will fly down, I have got 2x1mm2 down no problem.

 

[HappyHippyDad]

I think it's very easy for us to criticise another's work when only one side of the picture is shown. I'm not saying the work is great but without hearing the electricians point of view it's difficult to form a reliable viewpoint.

 

[westward10]

Of course it is easy to criticise but the use of that two gang box with the end broken open to install the cables leaves you open to it. Regardless of any restrictions put in place by the client you have to sometimes draw a line and say, this isn't going to work we need to review the situation.

 

[Mike Johnson]

Received this in reply:

Good morning Mike,



Further to your ‘forum’ discussion, the insulation of both H6242Y & 6491X PVC singles are both stated in their relevant standards as insulation grade ‘TI1’ to BS EN 50363-3 and are dimensionally similar, however, both are manufactured to different British Standards (BS 6004:2012 & BS EN 50525-2-31:2011) and are therefore subjected to a differing schedule of tests.

Please note also, that the cores within a H6242Y ‘Twin + Earth cable would NOT have the relevant markings on them therefore making them non-compliant with the BS EN 50252-2-31 standard.

For information, I have attached our data sheets for the two cable groups mentioned.

I hope this helps to clarify.

So it would seem they are the same, but don't have the relevant markings on them or subject to the relevant test to be used as single core.

 

[Vortigern]

Thats not very conclusive though. You would have to have and read the relevant standards to be sure.

 

[James]

Thats not very conclusive though. You would have to have and read the relevant standards to be sure.

I think it is enough info, the two cables are similar in size but made to different standards and tested to different standards.

The same could be said for most cables of the same conductor size.
That’s why we have different standards for different cables suitable for use in different environments.

 

[Pete999]

Thats not very conclusive though. You would have to have and read the relevant standards to be sure.

Agree was the wiring situation explained fully to them? you have to realise a lot of the guys at the manufacturers, although well intentions were prevalent, they have very little practical experience, and are quoting from the company's profile and with respect to them they are desk jockeys and may have little or no practical experience, thanks for the update anyway.

 

[littlespark]

Late to the party.

Personally, i dont think stripped T&E and pushing the cores down conduit is compliant, and the reply from the cable manufacturers implies it is wrong by saying the inner cores are not tested the same as singles.

Did i read the house was built in 50's? In that case the conduit may be 3/4 inch rather than 20mm... the internal diameter of which is marginally smaller and could make all the difference to what could be pulled through.

There is also a capacity table somewhere that states how many singles can be pulled through a conduit, which is less than the number of singles that can physically fit.


I dont know if they're still available, but there used to be "push on" adaptors that gripped the metal conduit and had a 20mm thread and bush. These could have been used to attach boxes at the top of the conduits.

 

[Vortigern]

It is easy to say it is non compliant but no one is coming up with what they would say in say an EICR. What is the non compliance? I am not saying it is good or acceptable practice or compliant just thinking it through properly. I have a ricked back so stuck at home and taking it out on here.

 

[Pretty Mouth]

It is easy to say it is non compliant but no one is coming up with what they would say in say an EICR. What is the non compliance? I am not saying it is good or acceptable practice or compliant just thinking it through properly. I have a ricked back so stuck at home and taking it out on here.

I suppose the non maintenance free boxes under the floor boards would get a C3, though far from a big deal. The patress could be a C1 if the hole is big enough to get a finger in, otherwise no code. 1950s, I assume that conduit was the clamp together stuff so likely isn't earthed. C3 if the conduit is not accessible to touch, C2 if it is.