Just one T+E to ceiling light

[Kioannis]

Hello

I would appreciate some advice. I am installing a sound-proofed suspended ceiling. It is virtually airtight as every layer is sealed individually.

In order to maintain the integrity of the soundproofing I can only have one T+E coming through the ceiling for the light fitting. No chance for holes with junction box.

For the reason above the light in each room will be a radial twin and earth from the CU to each room.

So my question is:

Is it an acceptable practice to bring the supply from the CU to the switch first, and then have only one T+E going up to the ceiling light?

I will use connector block for the neutral to continue up to the light and the L will be interrupted by the switch.

That way if a fault was to occur all the connections would be easily accessible inside the backbox rather than having to break a very complicated ceiling construction.


I can't think of a regulation to oppose this practice but your input will be greatly appreciated as in my job I don't practice domestic electrical installations, rather control circuits.

Many thanks
Kioannis

 

[Grant webber]

Yes fairly common way to wire lights these days

 

[Strima]

No problems going through the switch first. This will also provide a neutral for smart switches in the future as an added bonus.

 

[Andy78]

More than acceptable to loop at the switch, always best to have no hidden joints in cables.
If you use Hager Sollysta switches you'll find a dedicated neutral loop terminal to avoid the use of a connector block.

 

[Kioannis]

Thank you all, these are great replies and a relief as I couldn't think of another way of doing it.

In terms of the tails I will terminate them in a XL Wago box in an accessible area next to the consumer unit so I don't end up having 6 cables going into the CU.

Great point about the smart switches, thanks.

 

[Andy78]

Thank you all, these are great replies and a relief as I couldn't think of another way of doing it.

In terms of the tails I will terminate them in a XL Wago box in an accessible area next to the consumer unit so I don't end up having 6 cables going into the CU.

Great point about the smart switches, thanks.

If the sound proofing methods will allow three cables at the switches then just loop between the switches taking switched line and neutrals to each light. This would avoid the wagobox and multiple cables at the CU.

If this job is in a domestic dwelling then new circuits are notifiable to building control.

 

[Kioannis]

Thanks for this suggestion, I will re-draw tomorrow and see if this works out better. I can see your suggestion being easy to implement in two of the rooms.

If this job is in a domestic dwelling then new circuits are notifiable to building

That is valuable information, but does it apply in my case where it's just the wiring updated/rerouted? (It's all wired in singles at the moment.

 

[Andy78]

Thanks for this suggestion, I will re-draw tomorrow and see if this works out better. I can see your suggestion being easy to implement in two of the rooms.



That is valuable information, but does it apply in my case where it's just the wiring updated/rerouted? (It's all wired in singles at the moment.

If you are completely rewiring a circuit from circuit breaker to all points along new routes then it is a new circuit. This should be notified to building control and this is most easily done by an electrician that is part of a competent persons scheme.

You sound knowledgeable in some areas and not in others. Are you an electrician ?

 

[Kioannis]

If you are completely rewiring a circuit from circuit breaker to all points along new routes then it is a new circuit. This should be notified to building control and this is most easily done by an electrician that is part of a competent persons scheme.

You sound knowledgeable in some areas and not in others. Are you an electrician ?

Yes, however I don't work in domestic at all, my job is on control circuits for waste and recycling etc.

If you don't mind, is this notifiable before I start the works, or does it take multiple inspections as of and when I will be finishing each room because I will be working at one room at a time.

Could you point me to the right direction in regards to getting the right person in?

 

[Andy78]

Yes, however I don't work in domestic at all, my job is on control circuits for waste and recycling etc.

If you don't mind, is this notifiable before I start the works, or does it take multiple inspections as of and when I will be finishing each room because I will be working at one room at a time.

Could you point me to the right direction in regards to getting the right person in?

If you are notifying it yourself then you would need to contact the local building control office and ask their fee, this could be in the few hundreds and would involve the multiple inspections you mentioned, typically at first and second fix. This would need to be before the work starts.

You could try a third party scheme as run by Stroma and Napit. Contacting them could put you in touch with a local contractor on their third party scheme who would repeat the multiple inspection approach, but it might be cheaper.

Third option is to contact a local registered spark and see how involved they would be happy for you to be in this job and them still notify it.

 

[Kioannis]

If you are notifying it yourself then you would need to contact the local building control office and ask their fee, this could be in the few hundreds and would involve the multiple inspections you mentioned, typically at first and second fix. This would need to be before the work starts.

You could try a third party scheme as run by Stroma and Napit. Contacting them could put you in touch with a local contractor on their third party scheme who would repeat the multiple inspection approach, but it might be cheaper.

Third option is to contact a local registered spark and see how involved they would be happy for you to be in this job and them still notify it.

Thanks for your answer Andy, I appreciate you spending the time. While I was waiting for your message I was looking at the CP Register and found a few electricians local to me who appear to be NIC EIC and some others stroma and napit. I will contact them tomorrow and find out if they could come around, have a look and discuss the options from there. To be honest I would like to be involved as I need the experience for my career development so hopefully they will be willing to work with me.

 

[JK-Electrical]

More than acceptable to loop at the switch, always best to have no hidden joints in cables.
If you use Hager Sollysta switches you'll find a dedicated neutral loop terminal to avoid the use of a connector block.

Schneider Lisse switches also have a dedicated neutral loop. Very convenient indeed!

 

[telectrix]

debatable whether it's a new circuit or not. existing circuit is being altered by replacing old cable (maintenance) and re-routing of cables (and addition of accessories) (alteration).

 

[Andy78]

debatable whether it's a new circuit or not. existing circuit is being altered by replacing old cable (maintenance) and re-routing of cables (and addition of accessories) (alteration).

If that's not a new circuit then Trigger still has his dad's old broom.

 

[Kioannis]

Well, we have a divergence of opinions here. I suppose it boils down to what the electrician who will do the certification feels its right, correct?

 

[telectrix]

If that's not a new circuit then Trigger still has his dad's old broom.

of course he has. 7 new heads and 3 new handles, but it's only an alteration.

 

[Kioannis]

of course he has. 7 new heads and 3 new handles, but it's only an alteration.

Minor alteration I shall add.

 

[Midwest]

IMO, if all of the existing circuit is being replaced, then thats a rewire and would need notification. If one bit of the old remains, its an addition or alteration. Its splitting hairs, but the whole idea of Part P, is the work should be carried out by a competent electrician.

 

[Kioannis]

IMO, if all of the existing circuit is being replaced, then thats a rewire and would need notification. If one bit of the old remains, its an addition or alteration. Its splitting hairs, but the whole idea of Part P, is the work should be carried out by a competent electrician.

Does having passed the 17th edition characterise me as "competent person" according to the definition at the start of the book? That's a legitimate question.

 

[telectrix]

no. it just shows that you can look the answers up in a book ( with the caveat that you have a fair grasp of the regs.). notwithstanding, you could know the regs.100% and still be unable to fix a back box to a wall..

 

[Midwest]

Where I work now as maintenance, there's a quite knowledgeable guy whose done all sorts of work over the years, plumbing, welding, building management systems, he does know his stuff. When I started he asked what trade I had been in, electrician. Yeah me too he said, done the 17th.

 

[Kioannis]

Where I work now as maintenance, there's a quite knowledgeable guy whose done all sorts of work over the years, plumbing, welding, building management systems, he does know his stuff. When I started he asked what trade I had been in, electrician. Yeah me too he said, done the 17th.

Well, we work on compactors and balers, on a daily basis I work on pumps, directional valves, control circuits, PLC's, as well as welding and all the mechanical side, however it's time for a change of tack and I want to go back into electrical installations, used to enjoy it more.

I'm looking for someone who could mentor me career - wise but everyone's too busy.

 

[Dave OCD]

Kioannis - Apologies if this has already been mentioned but if it's easier for you loop the feeds from switch to switch rather than running each switch feed back to the CU location.