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

 

[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.