2 gang switch with a lot going on

[DonClif]

Hi all,
On my way home today I was asked to pop into a new customer and have a quick look at a lighting fault.
I'm still learning, but have a pretty solid grasp on testing, and reasonably on it with fault finding, so I was happy to see what I could sus out in a brief visit, before we made an 'official visit'.
There was an outdoor light operated from a 2G switch in the kitchen. All in 2 plate, from what I could tell.
The right was only feeding 9 LED spots, and the left only the outside like (as far as I was told, and could figure out in my 30 mins there)
What surprised me was the amount of conductors in the switch, and the way it was wired meant that L2 on the left was never receiving power.
I've not used Crabtree switches, but I'd expect L1 as common, but the feed seemed to be looped from L3 to L3, making L2 useless.

I've had a long week so go easy on me if I'm being thick.
And obviously I'll be asking the boss when it comes to it, but it's bugging me.

Cheers

 

[UNG]

Looks like both switches are 2 way'd to other switches, the live feed and switch wires are on L2 & L3 with a 3 & E to the other switches

 

[kerching]

Same as this BUT in your case the "Landing light" ( in this diagram) is off the lower switch. It’s a standard two way sometimes called a 'conversion'

 

[binky]

Looping in / out feeds at the switches rather than the old fashion way of doing that at a ceiling rose is increasingly popular. I'm not a great fan of doing things this way for the obvious reasons you just found..However, at least the cables have been marked.

 

[Alarmist]

Hi all,
On my way home today I was asked to pop into a new customer and have a quick look at a lighting fault.
I'm still learning, but have a pretty solid grasp on testing, and reasonably on it with fault finding, so I was happy to see what I could sus out in a brief visit, before we made an 'official visit'.
There was an outdoor light operated from a 2G switch in the kitchen. All in 2 plate, from what I could tell.
The right was only feeding 9 LED spots, and the left only the outside like (as far as I was told, and could figure out in my 30 mins there)
What surprised me was the amount of conductors in the switch, and the way it was wired meant that L2 on the left was never receiving power.
I've not used Crabtree switches, but I'd expect L1 as common, but the feed seemed to be looped from L3 to L3, making L2 useless.

I've had a long week so go easy on me if I'm being thick.
And obviously I'll be asking the boss when it comes to it, but it's bugging me.

Cheers

Get your test meter on the switch to positively (sorry) identify each terminal, assume makes an *** of You And Me.