Domestic Advice On Rewire Of Lighting Circuit

[Midwest]

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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.