Advice On Rewire Of Lighting Circuit

[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.

 

[Pete999]

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.

So what is your point?

 

[Wilko]

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.

If I was round for a Report I expect I wouldn’t be able to see those JB and the circuits would test ok due to Wago .

 

[Pete999]

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.

Never mind the JBs what about the idiot idea of stuffing stripped off singles down some conduit?

 

[Pretty Mouth]

Never mind the JBs what about the idiot idea of stuffing stripped off singles down some conduit?

If the conduit was earthed, I would see little problem with that, other than the sharp edge at the point the cable exits at the top

 

[Vortigern]

So what is your point?

My "point" @Pete999 is WHAT IS NON COMPLIANT

 

[James]

132.7 type of wiring and method of instalation
133.1.1 and 133.1.3 Selection of electrical equipment
134.1.1 good workmanship
510.3 compliance with instructions
511 compliance with standards
522.8.1 cable supports and enclosures

hows that for starters?

 

[Vortigern]

132.7 type of wiring and method of instalation

Not relevant

133.1.1 and 133.1.3 Selection of electrical equipment

Not relevant as you can operate outside of British or Harmonised standard where certification is provided to show it is at least as safe.
it refers to electrical equipment not cable

134.1.1 good workmanship

Maybe true

510.3 compliance with instructions

What instructions?

511 compliance with standards

We have seen standards but cannot view them, only the numbers so cannot comment (or afford them)

522.8.1 cable supports and enclosures

I cannot really see damage occurring so I think irrelevant and looking at the next reg you could just as easily say it agrees it is an acceptable method.

hows that for starters?

 

[Vortigern]

I know we see things which we are intuitively disgusted at or detest, but that is not something you can write on a cert. C2 cable is disgusting - is just plain nonsense. My whole point being it may be bad practice, it may look bad but really speaking how does it seriously cause danger to livestock of person. As I say I have nothing better to do, not really agreeing or defending such sloppy work but I like to be clear when I say that is a problem to a client and be able to quote a reg that actually makes unequivocal sense, not just have an emotional outburst, it's just not professional and is an offence to reason. I just feel it's like those cowboys who with a sharp intake of breath, "no earth you'll have to have a rewire","no rcd, you'll have to have a new cu madam"

 

[Pete999]

My "point" @Pete999 is WHAT IS NON COMPLIANT

Most of the installation

 

[James]

I am not arguing with you here, @Vortigern .
i suspect it would not be your choice of instalation method.
i am trying to put some actual reg numbers into the conversation to debate.

 

[westward10]

A non compliance does not necessarily pose a risk to life or health. Because unsheathed conductors have been installed and the conduit is open ended the containment system is incomplete. The two gang back box is essentially broken and cable ties are not appropriate for ad hoc cable restraint.
I don't believe anyone would go home, put their feet up and think yep I did a good job there.

 

[Vortigern]

I am debating personally. No hint of argument. I think 134 good workmanship is the only reg I can see that may be relevant and I have had a look at them all to see if there is merit and I think it is on the edge for a of what you introduce. I have no doubt I could put them all into a report and rely on the fact no one would really check them and assume there has been an egregious failure of the installation and compliance which would not really be the case.

 

[James]

James said:
132.7 type of wiring and method of instalation

Not relevant

The choice of the type of wiring system and the method of instalation shall include consideration of the following

i The nature of the location (probably nor relevant)
ii The nature of the structure supporting the wiring (hmm, single insulation entering a sharp conduit) maybe

iii to vi not relevant

vii other external influences (e.g. mechanical, thermal, and those associated with fire) to which the wiring is likley to be exposed to during the erection of the electrical instalation or service.

 

[Vortigern]

Most of the installation

'fank gawd you don't work for NICEIC

 

[Vortigern]

other external influences (e.g. mechanical,

Yes I could actually see that one. If someone put a heavy item to store up there and plonked it on that wire, or tripped/stood on it, there could certainly be a big bang so definitely concede the point there, and it is quite likely as a possible event. If it was earthed though....

 

[ipf]

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.

Damaged split conduit is in a wall is a serious, unseen hazard to fresh cabling installed.....especially after stripping T/3c+E, as described. It could well have taken a fair bit of pulling in, too.
I can't see how taping alters the fact that it's singes in steel conduit and, as such, said conduit should be earthed.

 

[HappyHippyDad]

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.

I was kind of aiming it generically Westward, not at you.

 

[James]

James said:
133.1.1 and 133.1.3 Selection of electrical equipment

Not relevant as you can operate outside of British or Harmonised standard where certification is provided to show it is at least as safe.
it refers to electrical equipment not cable
.......................................................................................

Look up equipment in the definitions, it includes wiring systems.

133.1.1 Every item of equipment shall comply with the appropriate British or harmonized standard. in the absence of such a standard, reference shall be made to the appropriate IEC standard or the appropriate standard of another country.

133.1.2 where there are no applicable standards, the item of equipment concerned shall be selected by special agreement with the person specifying the installation and the installer.

133.1.3 where equipment to be used is not in accordance with 133.1.1 or is used outside the scope of its standard, the designer or other person specifying the installation shall confirm that the equipment provides at least the same degree of safety as that afforded by compliance with the regulations. such use shall be recorded on the appropriate electrical cert.

..............................................................................
so, a cable manufacturer has confirmed that the inner cores of twin and earth do not adhere to the standards required for singles in conduit.
there are standard cable types available that are suitable for installing in conduit.
by choosing a cable that is not designed for the method of install that you are using, we must be going down the 133.1.3 route?

how are we going to confirm that the cable selected provides at least the same degree of safety as complying with the regs? after all there is an off the shelf cable designed to do the job but we have decided to use the inner cores of a cable and by disassembling it, we have reduced its safety level.
the manufacturer has said the insulation is of similar size but manufactured and tested to a different standard.

its not an something i would like to defend myself in court for.

For every installation that you see, where you look at it and think "that's a bit rough" there is a reg in the book to back it up with.

 

[HappyHippyDad]

Perhaps a piece of chewing gum around the top of the conduit?

 

[HappyHippyDad]

Thought we should bring the temperature down a little

 

[James]

Thought we should bring the temperature down a little

i was just beginning to have fun!

but you are right, i could do with a cold beer. time to put down the book of many words that can be interpreted in many ways.

p.s. gum round the top of the conduit may be acceptable if there are no applicable standards and it is agreed between specifier and installer by special agreement!!!

 

[littlespark]

Peppermint or fruity?

 

[Vortigern]

A well rounded and good argument you convinced me @James, thanks for the input it's certainly food for thought.

 

[Vortigern]

@Pete999, you pressed the more info at my comment re NICEIC. I was just observing you seem to have very high standards and it would make an assessment a ball breaking experience I think. Most men would be crying. But on the bright side at least you would only be certifying top men. Nothing sinister in it, was an attempt at humour.

 

[Vortigern]

Thought we should bring the temperature down a littl

A spirited debate does not mean a high termperature @happyhippydad I did hug a tree before my replies.

 

[SJD]

I realise it is somewhat late to be suggesting this, ... the problem as I understand it is the conduit is round is not going to take 2x 1.0mm2 flat T&E cables (assuming both switches just need 2 cores & earth).

So would using 4-core & earth round cable with solid cores have been acceptable, for example:
https://www.electricaldirect.co.uk/product/prysmian-4-core-and-earth-cable-15mmx100m-red-888110

Plus something to protect the sharp edge at the top of the conduit, e.g. I've used glue-lined heat shrink in the past, folded over and into the conduit (space permitting).

Obviously this cable would need splitting into the two circuits, e.g. at a Wago box somewhere.

 

[Vortigern]

It need five core and earth as it is a two way switch one of them. But yes I agree.

 

[telectrix]

A well rounded and good argument you convinced me @James, thanks for the input it's certainly food for thought.

pity the conduit was not as well rounded. ans as for chewing gum.... YUK. use blu-tac.

 

[James]

A well rounded and good argument you convinced me @James, thanks for the input it's certainly food for thought.

Thank you @Vortigern
I did flick through the book for points to raise, but not just stick a pin in a page and see what came up. Some thought went into the process!!

As you say, it is all food for thought.

 

[Micktw68]

Pete999
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,
Its not my house Pete. I was commenting on the install.

 

[Master Mech]

Well I did not expect this to create so much debate so thanks to everyone for taking the time to contribute, it really is greatly appreciated.

So am I right in saying that we are all in agreement now that the unsheathed twin & earth cores fed down a metal conduit that is unearthed is not acceptable?

Seems that the junction boxes are not great but not dangerous either? A couple a Wago boxes relevant for the connector type used would solve that problem?

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.

 

[Midwest]

Seems a bit busy for a 1 gang 1 way switch. What does the other switch do? Sure he’s not earthed the back box, and so the split conduit (if the correct fittings have been used)?

 

[Master Mech]

Seems a bit busy for a 1 gang 1 way switch. What does the other switch do? Sure he’s not earthed the back box, and so the split conduit (if the correct fittings have been used)?

The switch on the other side of the wall is a two gang switch controlling a pedant & some downlights hence it being two gang.

Because the wires running down the wall are unsheathed he has joined the wires inside the back box & then ran a sheathed piece of three core cable out the back of pictured back box to the other one on the other side of the wall.

The split conduit stops in the wall & does not attach to the back box.

From what I have been told:

The 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.

No idea if this is correct.

 

[westward10]

Agree with @Midwest those back boxes do not appear to be earthed as the cpcs are connected into an isolated push fit connector. They definitely need to be earthed.

 

[Master Mech]

Seems the back box is earthed.

 

[Pete999]

Seems the back box is earthed.

Still a lash up though Nate, good morning

 

[westward10]

Seems the back box is earthed.

Fair enough didn't spot that.

 

[Master Mech]

I know it is really hard to tell off just pictures over the internet but do you still think it would be possible to get five 6181Y wires down that single run of conduit?

That is if it is acceptable to only run one earth wire down & split it between the back boxes?

I have never seen 6181Y in person so no idea how thick the insulation is.

 

[westward10]

I know it is really hard to tell off just pictures over the internet but do you still think it would be possible to get five 6181Y wires down that single run of conduit?

That is if it is acceptable to only run one earth wire down & split it between the back boxes?

I have never seen 6181Y in person so no idea how thick the insulation is.

Difficult to say as you mentioned some of the tubes are flattened. 1mm 6181Y is approximately 4mm diameter but one will have to incorporate a cpc so is slightly larger. As I said before you would have to try each tube before committing to this method.

 

[Master Mech]

Difficult to say as you mentioned some of the tubes are flattened. 1mm 6181Y is approximately 4mm diameter but one will have to incorporate a cpc so is slightly larger. As I said before you would have to try each tube before committing to this method.

Fair enough, at least I have this option open to me now as if you had not suggested it I would never even know this product existed so many thanks for that.

If it is feasible it will be much cheaper than Quinetic switches but again I have them to fall back on if all else fails.

I guess because 6181Y is double insulated it can just be ran to the junction box in the loft?

I can see 6181Y cable listed on the CEF website but cannot find one with a CPC attached, is a different model of cable?

Would it be acceptable to run just another 6181Y 1.0mm cable for the CPC & sleeve it with earth sleeving or is this a no go?