AM2 Lighting

[Engineer54]

There's valid reasons for both methods, neither method has preference in regs so it would be a combination of personal preference and the requirements of the particular installation you're working on.


In my country it's standard domestic and commercial installation practice to loop the entire supply as a radial through the switches and just run a 3-wire switched supply to the light fitting.

What wiring system do you use mostly on domestic commercial in SA?? Would it be PVC conduit and singles??

 

[KAS1]

I remember when all the old "Police houses" in my area were all conduit / singles, no loop in loop out at the lights then for the lives (that was done at the switches) but they still didn't take neutrals to switches for the sake of it. I find it amazing that people are taking neutrals to switches for no reason, agreed when they are required, such as DP isolation or other smart switches no problem. I've used photo cells that have pulsed neutrals which required a retractive switch, so the neutral was required. However I still don't understand the logic for neutrals at switches if not required, perhaps I'm missing something................

 

[ackbarthestar]

So what don't you understand about the term ''loop feeding through switches''??

I don't have anything against a neutral at a switch, ...if and when a neutral is actually required. What i don't like or accept is looping through switches. Which seems to have become more common since the hoards of Electrical Trainee hit the industry, and the overall standard of collage lecturers, literary fell through the floor!!

The accepted wiring convention for singles in conduit has always been 2-plate, loop the neutrals at the lights and the feeds at the switches. Your suggestion appears to be a 3-plate variant. I've not seen so much of that, as a specified new install, although i have found variations of using a mixture of 2 and 3 plate on lighting circuits when I&Ting. I usually record such wiring without a code.

 

[Marvo]

What wiring system do you use mostly on domestic commercial in SA?? Would it be PVC conduit and singles??

Usually it would be pvc conduit and singles or more increasingly nowadays conduit and flat twin I assume because there's little price difference and it would save installation time.


I'm not familiar with the '2-plate' and '3-plate' terminology, maybe you can give me a quick rundown.....

 

[ackbarthestar]

Usually it would be pvc conduit and singles or more increasingly nowadays conduit and flat twin I assume because there's little price difference and it would save installation time.


I'm not familiar with the '2-plate' and '3-plate' terminology, maybe you can give me a quick rundown.....

Single in conduit = 2-plate

The 'plate' being the loop in

Neutrals are looped in at the lights
Feeds are looped in at the switches


Other wiring systems such as T&E, MIMS or even SWA if you like = '3-plate'

Both Neutrals and Feeds are looped in at the lights or switches

 

[ackbarthestar]

Thanks for that Marvo,
I forget that many of you who use this site have not trained under UK regulations so are unaware of our particular conventions.

I didn't mention flexibles in plastic conduit, as used in France and other countries. You often find twist connectors in terminal boxes where both the neutrals and Feeds are separately twisted together. This is as we (UK) would know it as '3-plate' wiring.

 

[Dan]

Just bumping some threads in the Electrical Wiring Theories and Regulations forum category here on our Electricians Forums. If this specific topic isn't current, just ignore it, it'll drop off the list in no time. However, if it's something you'd like to contribute to, feel free to reply and bring it back into current discussion.