Advice On Rewire Of Lighting Circuit

[westward10]

Sorry the one with a cpc is 6241Y.

 

[Midwest]

I don’t think replacing the unsheathed 6242y cables with 6181Y cables is a go’er, unless it’s for a single switch. The switch point you’ve posted is an example.

I think you need to raise your concerns with your electrician, to come up with an alternative plan, to the one you have initially agreed to. It might need a little bit of redecorating needs to happen. As to who will fund the alterations, is something you’ll have to discuss; but I think it might be primarily yourself.

 

[Mike Johnson]

Taking into account that the solution that was installed was agreed with the owner, if they do not like the result any alterations now will need to be paid for by the owner.

 

[westward10]

I disagree because it was not a solution, it did not work. He should have stopped and reviewed it with the client, not pressed on regardless.

 

[Mike Johnson]

I think that is where the problem lies with this discussion, that solution did work, we may not like it and it may not conform, but it did work.

 

[Master Mech]

Taking into account that the solution that was installed was agreed with the owner, if they do not like the result any alterations now will need to be paid for by the owner.

Whilst I can see where you are coming from he never asked me if this solution was acceptable to me.

I asked him at the time as I had concerns & he told me there was no issues with it & if he thought there was an issue I would expect him to not carry on with the work. I did not feel comfortable pressing the issue further at the time as I did not know how founded my concerns were.

Hence the reason I created this thread to find out if my concerns were founded. I now know there are issues with a work carried out so can with confidence raise them with the electrician.

Also nice to have options to discuss with him on how to resolve the issues that he himself may not be aware of.

 

[Intoelectrics]

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.

Fair enough, I wasn't pointing a finger, but I'm sure you can appreciate that sometimes folk only give you half the story.

 

[Master Mech]

If the conduit is big enough would this cable be suitable to use?

https://www.NoLinkingToThis/p/time-3185y-white-5-core-1mm-flexible-cable-5m-coil/68083

 

[Midwest]

I don’t see a problem with that, as long as it’s suitably sized; indeed I did suggest something similar earlier. The only issue I would have, is that this cable is connected to the fixed wiring with a suitable JB with suitable strain relief, and where it exits the split conduit, a suitable grommet is used.

BS7671 reg 521.9.1 (I think) mention use of flexible cable used in fixed wiring. Only caveat is using heavy duty flex. But in your case I can not see it be subject to any mechanical damage.

 

[Pete999]

I don’t see a problem with that, as long as it’s suitably sized; indeed I did suggest something similar earlier. The only issue I would have, is that this cable is connected to the fixed wiring with a suitable JB with suitable strain relief, and where it exits the split conduit, a suitable grommet is used.

BS7671 reg 521.9.1 (I think) mention use of flexible cable used in fixed wiring. Only caveat is using heavy duty flex. But in your case I can not see it be subject to any mechanical damage.

Good thought Mate, I think the answer is to string the So called Electrician up that Decided to strip the Mech Protection from the cables and thread them down a conduit,and chuck his tools away, do every one a favour and rid the world of these cowboys and stop them poncing on the unsuspecting general public, and hear was I thinking that only suspect car dealers were up to this malarkey.

 

[Master Mech]

So I am still waiting for the electrician to come back, I have heard from him & have not gotten a date from him on when he will return.

I do have another question regarding the grouping factor that will be applied to the three cables he has installed in the conduit. The cables/circuits & MCB's are as follows :

4mm2 T&E - 32 amp MCB

2.5mm2 T&E - 20 amp MCB

1.0mm2 T&E - 6 amp MCB

Am I correct in saying that because the conduit contains three circuits the grouping correction factor would be 0.70?

Then I am totally lost on how to apply this correction factor to these these circuits.

 

[Pete999]

Is this a continuous solid conduit system, or an oval conduit for burying in the wall the use of twin and earth suggests the later, can you confirm please?

 

[Mike Johnson]

That must be a very large conduit to accommodate those three cables and keep within the requirements of BS 7671 and not exceed 45% of the net cross-sectional area.

 

[Master Mech]

Is this a continuous solid conduit system, or an oval conduit for burying in the wall the use of twin and earth suggests the later, can you confirm please?

That must be a very large conduit to accommodate those three cables and keep within the requirements of BS 7671 and not exceed 45% of the net cross-sectional area.

He has used 25mm black conduit that is round, it is on the exterior wall of the house.

 

[Pete999]

He has used 25mm black conduit that is round, it is on the exterior wall of the house.

 

[Mike Johnson]

Ok I will bite, 25mm dia conduit has an internal area of 78.5mm sq, 4mm T&E has a nominal dia of 37mm sq so even without the 2.5 & 1 T&E the 45% space requirement is not maintained.

 

[Mike Johnson]

Sorry should have said "with the 2.5 and 1 the 45% space etc:

2.5mm T&E being 32mm sq and 1mm T&E being 24mm sq.

 

[Master Mech]

So in layman's terms there are to many cables for that size of conduit?

If the 4.0mm2 cable was removed would that compile with the regulations?

I presume this regulation is to prevent the cables from over heating?

 

[James]

So in layman's terms there are to many cables for that size of conduit?

If the 4.0mm2 cable was removed would that compile with the regulations?

I presume this regulation is to prevent the cables from over heating?

Also,to allow cables to be rawn in without damaging them

 

[Mike Johnson]

The cross section of T&E is a bit strange, as the cable is deemed to be the diameter of its major axis when in reality its anything but, so most electricians use a bit of common sense where this is concerned.

 

[Master Mech]

So would removing the 4.0mm2 T&E cable allow enough space to meet the 45% space requirement?

Also would you guy know what the regulation is called or the number?

I have a strong feeling what response I am going to get from the electrician when I mention this but I will try.

 

[Mike Johnson]

Short answer NO.
BS7671 Guidance note 3, page 28 2.6.3 Conduit Systems paragraph 3 Recommended quantity of cables for easy draw not exceeded during installation causing insulation damage; .......... Item should be inspected during the erection stage as the care and workmanship of the installer can be verified (522.8.1 and see On-Site Guide Appendix E)

My spoon has just worn out.

 

[Master Mech]

Short answer NO.
BS7671 Guidance note 3, page 28 2.6.3 Conduit Systems paragraph 3 Recommended quantity of cables for easy draw not exceeded during installation causing insulation damage; .......... Item should be inspected during the erection stage as the care and workmanship of the installer can be verified (522.8.1 and see On-Site Guide Appendix E)

My spoon has just worn out.

Many thanks for your time, help & patience.

Looks like I will be on the search for another electrician to put all these issues right which will be interesting as I am sure many will not want to put right another persons cock up.

Thanks again to everyone who has participated in this thread & for your input & advice.