How would you expect lights to be wired?

ericmark · Post by **ericmark** » Fri Aug 27, 2021 9:38 pm

I have worked with PLC's and SCADA, but most domestic electricians would not have a clue what I am talking about, and at 70 I have to face facts and realise at some point will not be able to DIY. In fact son will not leave me the ladders in case I use them. Which means not a clue what is behind the landing ceiling rose.

My wife has decided she wants a new landing light with all pretty dangling bits, I said I would not fit it, but darn son said no problem I will fit it, we are both industrial electricians. So light arrives and it has 5 GU10 bulbs, so one centre 4 outer seems good idea to have them separately switched, the hall switch is in a poor place, hard to reach, so using phone to switch on, or remote control seems good idea, so relay zigbee ordered and arrived, however this is where it has gone wrong.

The manual switching option uses ELV, not LV as expected. So the question arises how to wire? I know the hall switch has a neutral at the switch, as they had been swapped and caused the RCBO's to trip until I swapped them, My thoughts were to use the switched line to trigger the relay and permanent line to feed it, but there may not be a permanent line?

So want three ELV wires to landing light switch, so can manually switch light, but what about the LV supply, should I use a three gang switch, or should ELV and EV not go to same back box? Should I just use a connector block for the LV and have only the hall switch connected to the LV supply?

I am sure I can thread a triple and earth cable to switch back box, this would be brown, black, blue so unlikely to get mixed up with old colours, but in 10 years time, if some thing goes wrong and my son can't help, what would a domestic electrician expect to find? I can make it work, but want it so if I am not around and my widow calls an electrician he can work out what I have done and fix it.

So how are LV and ELV wiring normally done with domestic?

Scotty001 · Post by **Scotty001** » Sat Aug 28, 2021 6:55 am

As to "what would a domestic electrician expect to find"
Id say the answer is "anything"

If using a mix of wiring colours first you want a sticker on the cons unit advising that there is a mix of old and new wiring colours, I think the best way to issustrate what you have done for a future electrician is draw a small diagram and write what had been done, what is feeding what and where they get their feed and what the feed goes to. stick that in a plastic a4 wallet put a sticker on that says electrician read 1st and tape it to the Inside lid of the cons unit.

The electrician WON'T expect to find that but will be very glad they did (or not so happy if the planned on spending half the day figuring it out and billing for that time)

aeromech3 · Post by **aeromech3** » Sat Aug 28, 2021 10:05 am

No idea

Someone-Else · Post by **Someone-Else** » Sat Aug 28, 2021 3:49 pm

ericmark wrote: ↑Fri Aug 27, 2021 9:38 pm So how are LV and ELV wiring normally done with domestic?

You should always keep 12v separated from 230v, you can even buy segregated trunking (So you can have 12v in one past and 230 in the other)
Having said that, you can have them both in the same cable if all cores are insulated to the higher voltage.

Although you can, I still would not do it as today you know what it is and next time do you still remember, notes and drawings get lost.
Why can't you have 2 power supplies for this light and just switch the mains, everyone is a winner.
Also are you sure this light has two switched lives? not heard that one before.

Bob225 · Post by **Bob225** » Sat Aug 28, 2021 6:13 pm

If the fitting is 240v with elv switching, use the switch to turn the elv transformer on/off then there is no need to mess with wiring

wire colours don't matter* just flag them up to suit your needs with sleeves, heatshrink or id bands/beads

ericmark · Post by **ericmark** » Sun Aug 29, 2021 8:48 am

The zigbee unit does the voltage dropping, one side it has line in, neutral, Line 1 out and line 2 out, other side it has connections to switches, marked as not mains voltage, but does not say what voltage common lamp 1 and lamp 2. There are also two buttons on the unit to manually switch.

The main point is although zigbee controlled the extra low voltage control allows it to also be manually switched. Loads of room for it in the light fitting, could not bother wiring up the manual switches, but although my wife walks around with her phone glued to her, I don't so having manual switches suits me.