Loop in method for Lighting Circuits

Indeed, but I am with Sparkingchip - we cannot realistically make the all systems unconditionally safe, and we should not try, rather we should make it well engineered, and then so long as we make sure the how to do  it information is available, that is all that is reasonable to do, which actually given the web has never been easier.

If a few  folk cannot be bothered to work out what to do before they start, then they can pay up for someone else to sort it out when they muck up, as they do with plumbing and woodwork too.

Loop in at switch prevents smoke detectors being wired up to an adjacent pendant.

Chris

I carry 13 amp plugs on my van as stock, on Monday I went to do some odd jobs at a church that is being renovated, during the day I replaced three plugs.


Two were on some of the builders 110 volt tool transformers and the third one was on the church hearing aid induction loop system, just straightforward undemanding electrical maintenance work.


Normally no one will throw an appliance away because the moulded plug needs replacing, they will buy a replacement plug that normally comes with a fitting instructions card attached to it. Yet large numbers of people seem incapable of following simple instructions and fitting a replacement plug.


Yet somehow we are supposed install fixed electrical installations that any untrained person can maintain or alter when there are so many people who cannot understand the instructions packed with plugs or included with an appliance telling them how to correctly wire the two or three conductors in a flex into a plug.


So long as the lighting circuit is installed correctly with the conductors correctly identified by colour I am not going to beat myself up worrying if a DIYer will understand how it is wired.


Having said that I usually aim to just present a switched live, neutral and CPC at light fittings, but if it ends up with a permanent live at the light fitting as well, so be it.


I have been caught out working on existing installations where there has been a permanent live from one circuit in a light pendant and ceiling rose set with a switched live from a different circuit, that was just silly. However no one should be surprised if there are two or more circuits running through a multi-gang light switch.


Indeed I have worked on lighting circuits where there are lives which are red, black, brown, blue, grey and yellow, whilst neutrals are black and blue. All you do is over sleeve everything in brown and blue as appropriate then connect them up before putting a sticker on the consumer unit warning there are mixed colours.


You certainly do not start worrying about if a DIYer will understand how a four gang light switch box is wired when the back box contains a rainbow of colours, particularly as there could be lights with single switching, two way switching or multiple switching using intermediate switches along with presence detectors, timers, photo cell switches and so on and forth connected through it.


It is up to the DIYer to get up to speed or leave them alone.


Andy Betteridge

"It is up to the DIYer to get up to speed or leave them alone "


Spot on there Andy.


Sadly some people are clueless when even wiring a plug (aka plugtop) even some "electricians".

It used to crop up in senior school back in the day - How to wire a plug - teachers usually taught it mostly right in most cases.

Todays crop of teanagers and young adults often seem clueless.

That was in a bygone age where we used two marvel tins linked by taught string as a telephone and a match head wrapped in silver foil as a bangor. I will not mention mixing our own gunpowder.

I live my luxury life style due to D.I.Y.er bodges. It is Saturday morning, wife nags husband to get new decorative light installed. They buy one at the local shed. He finds woodworm eaten steps in garage and turns off the mains. He tries to fit the new light over the ceiling rose but the rose gets in the way, the ceiling rose is removed. "Have you finished yet" shouts wife, "I want it installed before X arrives".


Husband wires up new light fitting (or "luminaire" for the more exotic amongst us), he wires all reds together, all blacks together and may connect the bare earths, unsleeved , if the wind is blowing in the right direction.


Note. For younger viewers please read: He connects all blues together, and all browns together etc.


Light fitting is now installed. He turns mains back on, operates light switch and all lights now go off as the lighting fuse blows or M.C.B. trips off. Wife not happy.


He then calls me in after fiddling about trying to correct the fault for an hour with no success.


Gawd bless the D.I.Y.er.


Z.

Sounds familiar Zoom.


(Not the bit about my luxury lifestyle though! LOL)

Z - This is exactly what happened last week when a plumber friend wired up a light fitting, he got the switch live and neutral crossed as existing wires were unsleeved hence my original concern about loop in at ceiling rose's. He only need know flow and return!!!

I have a light fitting change to fo in a neighbours kitchen, the kitchen fitters started to do it but stopped because it “has reversed polarity”.


Assuming I find what I expect to find I will over sleeve the black on the switch wire brown along with the permanent live then dog them together with a Wago type push fit connector, leaving the a red live from the switch and black neutral to over sleeve in brown and blue respectively to connect the new light; and make the CPCs off all over fleeced in green/ yellow.


Built there could be a wild card to consider such as interconnected lights or single cables.


Always remember to check the lights still work in adjoining rooms!


Simples  ?‍?


Andy Betteridge

Conventionally with the 3 plate system, all reds were connected together at the ceiling rose at the centre terminal block with three terminals.  Red 1. Line supply....... Red. 2 Line looped out to next ceiling rose......Red 3 Dropped down to room light switch, normally in a T&E cable.


The black from the light switch was marked with red tape or red sleeving if you are lucky. This becomes the lamp holder line, or ceiling light line.


The black of the supply T&E is neutral and connects to the ceiling rose terminal with three terminals marked neutral, or at  one side of the three separate connectors.


The loop cable to the next ceiling rose connects its red to the centre terminal, (permanent line). Its black core connects to the neutral terminal using the second screw position.


The red from the switch (switched line) connects to the last outer terminal of the ceiling rose the terminal with just two screws.


The lamp holder connects to the two extreme outer terminal positions at the ceiling rose, switched line and neutral.


If you have just a load of wires hanging from the ceiling at the light position and the system is three plate wired, and you wish to terminate the wires correctly, just find the switch drop first. You could use a buzzer or a meter with a continuity buzzer facility or an Ohm meter. Just connect the meter leads to any pair of  red and black wires at the light position with the light switch on. When you hear the buzzer you have found the switch drop cable. When the switch is turned off continuity is lost and the buzzer will stop buzzing or continuity will show infinity Ohms. This confirms the switch drop cable.  Mark it accordingly and sleeve the black wire brown. All other wires are then easily terminated at the ceiling rose, their positions being obvious.


Z.