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

 

[Micktw68]

Thats pretty poor. Unsheathed inner cores of the T&E cabling is likely to be damaged on the sharp edges of the conduit, the containment and joint boxes is terrible .
a better solution if you wanted to avoid chasing/redecoration would have been the use of Quinetic wireless switches.

 

[Pete999]

Thats pretty poor. Unsheathed inner cores of the T&E cabling is likely to be damaged on the sharp edges of the conduit, the containment and joint boxes is terrible .
a better solution if you wanted to avoid chasing/redecoration would have been the use of Quinetic wireless switches.

Very poor workmanship striping all the mech protection off of the twin cable is very poor the inner cores of the twin, and earth are not designed to be used this way, not a very knowledgeable Electrician, nor is it compliant with the Regulations ( BS7671) PS Did you receive any certification from this so called Electrician? an EIC,

 

[James]

It’s not a good job, there are ways that it could have been done better.

I suspect that the original wiring was 1mm and they have used 1.5mm because it was what they had in the van.


Stripping back twin and earth to feed down conduit is not an installation method I would be happy to use.

 

[Dustydazzler]

On a fall rewire i would have expected the metal split tube ideally be removed and a new back box + plastic conduit be installed for the new cables.
As for all the random junction boxes , it’s not a bad job but again on a full rewire I would have preferred to have the connections at the switch.

 

[Mike Johnson]

Very poor workmanship striping all the mech protection off of the twin cable is very poor the inner cores of the twin, and earth are not designed to be used this way, not a very knowledgeable Electrician, nor is it compliant with the Regulations ( BS7671) PS Did you receive any certification from this so called Electrician? an EIC,

Genuine question, are the inner cores of T&E different to single cores?
Can you also point out which Regulation it contravenes?

Must admit I wonder if using single cores of 1mm would have solved the problem if indeed they did use 1.5mm, difficult to see.

I would also like to see the EIC especially the CPC resistance/insulation values.

 

[Wilko]

It’s good that Wago connectors have been used, but none of those junction boxes are suitable to be placed in the building fabric. For reference Regulation 526.3 applies. If I’ve understood correctly how these junction boxes are to be placed (in walls and under floors) then for me this work is non compliant. As well as messy.

 

[Baddegg]

Can’t see the point in using wagos without the enclosures?....Not sure if it is against regs but not something I’d have done with regards the switch drops conduit.....

 

[James]

Genuine question, are the inner cores of T&E different to single cores?
Can you also point out which Regulation it contravenes?

Must admit I wonder if using single cores of 1mm would have solved the problem if indeed they did use 1.5mm, difficult to see.

I would also like to see the EIC especially the CPC resistance/insulation values.

Inner cores of T+E are not designed to give any significant mechanical protection (this is dealt with by the outer sheaf)

The cover on single cores is thicker and often a harder grade of pvc.
Also, it has been tested and certified for installation and use in conduit, including resisting damage caused by pulling down conduits.

 

[Master Mech]

Very poor workmanship striping all the mech protection off of the twin cable is very poor the inner cores of the twin, and earth are not designed to be used this way, not a very knowledgeable Electrician, nor is it compliant with the Regulations ( BS7671) PS Did you receive any certification from this so called Electrician? an EIC,

He finished the job Friday & says I will receive the certificate in around two weeks. I did say I thought that was a long time to wait & he said he has 30 days to issue the certificate & is very busy hence the delay.

It’s not a good job, there are ways that it could have been done better.

I suspect that the original wiring was 1mm and they have used 1.5mm because it was what they had in the van.


Stripping back twin and earth to feed down conduit is not an installation method I would be happy to use.

I am pretty sure he used 1.0mm as this is what was written on the sheath stripped off the cables I cleaned out of all the loft insulation.

Does using stripped T&E in conduit contravene the wiring regulations? If so this gives me something else to go back to him with.

It’s good that Wago connectors have been used, but none of those junction boxes are suitable to be placed in the building fabric. For reference Regulation 526.3 applies. If I’ve understood correctly how these junction boxes are to be placed (in walls and under floors) then for me this work is non compliant. As well as messy.

Would the appropriate Wagobox for the connector type solve the junction box issue?

Now I know about these Quinetic wireless switches that obviously would have been an option. Is there any other solutions that do not involve chasing the walls out that comply with the regulations?

 

[Mike Johnson]

Inner cores of T+E are not designed to give any significant mechanical protection (this is dealt with by the outer sheaf)

The cover on single cores is thicker and often a harder grade of pvc.
Also, it has been tested and certified for installation and use in conduit, including resisting damage caused by pulling down conduits.

Surely both types of cable have to meet the Thermoplastic criteria of withstanding 70deg C, in which case I can't see the manufacturer using a different grade of pvc on T&E, I think I will follow this up with Doncaster cables and see what they say.

 

[westward10]

If I was asked can I use the existing conduits I would find out first before committing. You can strip the outer sheath away however I would argue it should be correctly contained and I am not convinced an open ended conduit drop achieves this.
For a rewired circuit you avoid junction boxes at all costs whether they are maintenance free or not, in this case he has employed them no matter what the cost.

 

[Pete999]

Genuine question, are the inner cores of T&E different to single cores?
Can you also point out which Regulation it contravenes?

Must admit I wonder if using single cores of 1mm would have solved the problem if indeed they did use 1.5mm, difficult to see.

I would also like to see the EIC especially the CPC resistance/insulation values.

Can't tell you the reg no as I don't have a copy handy.
If you look at the BS number for single core cables used in conduit systems, they are different from TandE, plus the inner cores of T and E are what they are insulated inner cores and not designed for the purpose described in the OP.

 

[Pete999]

Surely both types of cable have to meet the Thermoplastic criteria of withstanding 70deg C, in which case I can't see the manufacturer using a different grade of pvc on T&E, I think I will follow this up with Doncaster cables and see what they say.

Don't think there is any difference in the PVC, it's the construction that counts, usage should be the criteria here horses for courses as the saying goes, you wouldn't use single cables to wire you're house unless they were designed for that purpose, and totally enclosed with conduit or trunking, would you????
Please let the forum know what Doncaster say, it will be interesting, plus why do they manufacture TandE the way they do with an outer sheath of Mech protection?

 

[Vortigern]

Thanks guys, that was one of my jobs. Anyway such a device (metal containment) for singles/T&E should technically be earthed which it is not. As @Wilko points out the JBs should be MF so replacing them with wago MF boxes would sort that. In order to stop thermal cycling and vibration causing any harm the JB should be affixed to the joists which Wago boxes have provision for so that would meet that criteria. I normally sleeve the three core as well. Essentially I see nothing too bad here, it could be improved but I do wonder why the OP does/did not have enough confidence in the spark in question to not go around after him and check his work. Any comments OP? I have once or twice been held to account by customers questioning methods of installation which comply with regs and it can be very difficult for the installer where there is no merit in such a lack of confidence. However there is some merit in the OP, in this case, but clearly the installation has been left a lot safer than when he started looking on the bright side.

 

[westward10]

PVC T&E and PVC singles are both manufactured to BS6004 and it would be assumed the insulation of the copper conductor is of an equivalent. If the sheath of the T&E is removed then it should be correctly contained as with singles after all the sheath is removed at accessories and within distribution boards.

 

[HappyHippyDad]

I agree that on a rewire junction boxes should be avoided, but sometimes we do use them when it's going to make live MUCH easier. That surface box is an odd choice but if it is in the loft then they do not need to be maintenance free, I have seen far far worse, at least there is no basic insulation showing and he has cable tied them to keep in place.

I cant comment on twin and earth being stripped back and put in metal conduit as I don't know if it's any different to singles, although from James's post it looks like it is. The metal conduit will certainly give greater protection than a piece of plastic. I don't like the sharp edges on it though, some heat shrink would have been better along with something to soften those edges. Plus it needs to be earthed, but perhaps it is.

 

[Master Mech]

The consumer unit is under the stairs & original lighting circuit comes out of the top of the consumer unit into the cavity inside the stairs making its way to under the floorboards of the landing.

All the cables going to & from the consumer unit are plastered into the wall & if I can avoid it I asked if it was possible to not chase the wall out. As you can tell I am not a fan of decorating

The solution he came up with was to drill a hole through the wall the consumer unit is mounted on which is an external wall & run a cable from the consumer unit in conduit on the outside of the house up to the loft.

From there he has split that feed in the loft for all the lights in the three bedrooms upstairs.

To be able to rewire the landing, hallway & dining room lights he used the switch drop for the landing light that also drops all the way under the landing floorboards. Then placed junction boxes under the landing floor boards to be able to supply the dining room & hallway lights.

I hope this all makes sense.

Thanks guys, that was one of my jobs. Anyway such a device (metal containment) for singles/T&E should technically be earthed which it is not. As @Wilko points out the JBs should be MF so replacing them with wago MF boxes would sort that. In order to stop thermal cycling and vibration causing any harm the JB should be affixed to the joists which Wago boxes have provision for so that would meet that criteria. I normally sleeve the three core as well. Essentially I see nothing too bad here, it could be improved but I do wonder why the OP does/did not have enough confidence in the spark in question to not go around after him and check his work. Any comments OP? I have once or twice been held to account by customers questioning methods of installation which comply with regs and it can be very difficult for the installer where there is no merit in such a lack of confidence. However there is some merit in the OP, in this case, but clearly the installation has been left a lot safer than when he started looking on the bright side.

I did question the electrician about some other work he carried out which did not end very well. He got very offended that I was questioning his work & that I did not trust him. He took it very personally.

I have another thread here about a radial he installed along with this circuit & when I asked him why he installed a 32 amp MCB on a 4mm2 cable that he ran in conduit with other cables he said it was fine & posed no risk.

I told him it did not meet the wiring regulations but apparently he has never had an issue in his years of experience & they were only guidelines.

 

[Master Mech]

Plus it needs to be earthed, but perhaps it is.

What's the best way to know if it's earthed?

Right now its just a piece of metal conduit plastered into the wall. It is not connected to the back box it drops to or anything on the other end in the loft.

 

[Pete999]

Thanks guys, that was one of my jobs. Anyway such a device (metal containment) for singles/T&E should technically be earthed which it is not. As @Wilko points out the JBs should be MF so replacing them with wago MF boxes would sort that. In order to stop thermal cycling and vibration causing any harm the JB should be affixed to the joists which Wago boxes have provision for so that would meet that criteria. I normally sleeve the three core as well. Essentially I see nothing too bad here, it could be improved but I do wonder why the OP does/did not have enough confidence in the spark in question to not go around after him and check his work. Any comments OP? I have once or twice been held to account by customers questioning methods of installation which comply with regs and it can be very difficult for the installer where there is no merit in such a lack of confidence. However there is some merit in the OP, in this case, but clearly the installation has been left a lot safer than when he started looking on the bright side.

"you see nothing to bad" what? stripping twin and earth and threading the cores down a conduit is not bad? it's downright disgraceful workmanship.