Permanent live for smoke alarms and emergency lighting

[Neptune]

Modern installations could be run via the switch however the vast majority are still looped at the light and have a neutral run to the switch.

I can concur that most older installations are looped at the ceiling. When this is the case, I find this configuration:

I note that this doesn't take a Neutral to the switch but you suggested that it does. Incidentally, this then presents issues with smart switches as most require a neutral wire.
Can you please clarify?

Thanks for your help.

 

[Neptune]

If the loop is at the light fitting the easiest thing to do is completely replace with a fitting which incorporates an emergency, something like this.

Robus Golf 10W LED With Pro-Diffuser IP65 330mm White 4000K Emergency - R100LEDE-01

Electrical2Go sell discount Robus Golf 10W LED With Pro-Diffuser IP65 330mm White 4000K Emergency with free & fast delivery available.

www.electrical2go.co.uk

That's a genius suggestion! Thanks

 

[Strima]

I can concur that most older installations are looped at the ceiling. When this is the case, I find this configuration:
View attachment 92283

I note that this doesn't take a Neutral to the switch but you suggested that it does. Incidentally, this then presents issues with smart switches as most require a neutral wire.
Can you please clarify?

Thanks for your help.

Only in recent years has BS7671 recommended running a neutral to the switch position to allow for future upgrades. You can get smart switches that work without a neutral but for the cost of a few meters of cable on a new build or rewire it makes sense to run a neutral in. Ideally the ceiling rose should be updated to allow for four cables rather than three but this is down to manufacturers etc to sort out.

So older installations there will be no neutral ran to the switch, sorry if I added confusion.

 

[Neptune]

sorry if I added confusion.

Makes sense now. Can you forward me a wiring diagram of the neutral being carried across to the please? I am wondering if this is then a 4 core cable...

 

[telectrix]

Makes sense now. Can you forward me a wiring diagram of the neutral being carried across to the please? I am wondering if this is then a 4 core cable...

on new work, you would generally use a 3 core/E cable from light to switch in order to provide a N at switch.

 

[Neptune]

on new work, you would generally use a 3 core/E cable from light to switch in order to provide a N at switch.

Where on the switch would this new Neutral wire connect?
Also, can I please confirm that you are proposing a 3 core and earth cable from the light to the switch under this configuration.

 

[BiddeldyBwah]

Where on the switch would this new Neutral wire connect?

It wouldn't normally, you'd put it in a connector block unless you were using a newer switch that has a provision for a neutral link on the actual light switch fitting.

Also, can I please confirm that you are proposing a 3 core and earth cable from the light to the switch under this configuration.

Personally i don't understand the comment about 3 core for an N at the switch, you can just do that with T+E. T+E feed in, T+E out to light, CPC N and SL all present.

Unless you want to use 3 core to put the perma live from switch to rose in order to loop in from the rose to the next light. Sure Telectrix will clarify (i am only a meagre apprentice at present.) EDIT: I get what he's saying now, i was thinking about it from a 'take from the switch' perspective not taking the feed to the rose.

That said, i would just get an electrician out to have a look. No point guess working it when you can just pay an expert to sort out the plan in about 10 minutes.

 

[Neptune]

It wouldn't normally, you'd put it in a connector block unless you were using a newer switch that has a provision for a neutral link on the actual light switch fitting.



Personally i don't understand the comment about 3 core for an N at the switch, you can just do that with T+E. T+E feed in, T+E out to light, CPC N and SL all present.

Unless you want to use 3 core to put the perma live from switch to rose in order to loop in from the rose to the next light. Sure Telectrix will clarify (i am only a meagre apprentice at present.) EDIT: I get what he's saying now, i was thinking about it from a 'take from the switch' perspective not taking the feed to the rose.

That said, i would just get an electrician out to have a look. No point guess working it when you can just pay an expert to sort out the plan in about 10 minutes.

Are we in agreement that a 3 core and earth cable would be required for this approach (from light to switch) and the neutral wire would be terminated in a wago behind the switch - in anticipation of smart switch, etc.

 

[BiddeldyBwah]

Are we in agreement that a 3 core and earth cable would be required for this approach (from light to switch) and the neutral wire would be terminated in a wago behind the switch - in anticipation of smart switch, etc.

If you mean taking the feed to the light fitting and needing a neutral at the light switch then yeah, it just makes sense to use 3core+e or 4 core and use the black as the switch live and grey as the neutral with sleeving. Shove the grey into the neutral bar on the ceiling rose and wago the other end.

Or, tell your electrician to do that, i mean.

 

[telectrix]

the wholepoint of 3 core/E is to have all possibles at both light and switch. i/e/ L. / S/L / N / E. then there's no chasing out of Mrs. Bloggs's new decor when she decides on some smart tat.