switch cable colours

mickward

Just a question I am posing.

at the back of a standard single pole light switch, it is marked "L1" and "Comm".

any I have ever opened or had to look at over the years normally always had the double insulated grey wire with the brown inner sheath, to both L1 and COMM.
This would say to me that when the electrician is wiring the house it does not matter which way around these are connected, (I think this works out true as the switch will work either way).

then why mark the switch L1 and Comm, or the real question should the switch wire be a different colour?

Thanks lads.

Calahonda52

Are most switches now now 2 way by default so u have L1 L2 Comm.
if done properly and consistently then anyone opening switch should be able to tell which was the unswitched live, not that u would ever rely on that and expect to live
Also the wire to the fitting from switch will be live when switch is on so ......

Irish Steve

The majority of manufacturers use the same mould and parts for 1 way and 2 way switches, and jsut don't fit the L2 terminal in a 1 way switch, so the L1 L2 Comm markings will appear on a 1 way switch.

It's only relatively recently that dual brown cables have been introduced for lighting switch drops, it saves having to sleeve the blue to indicate that it's not a neutral, which most of the time didn't get done. I've also seen the odd place where twin and earth was used for a 2 way light with the earth sleeved with a colour, which is not supposed to happen, but hey, there's plenty of examples of that sort of corner cutting if you look close enough.

Risteard81

Irish Steve wrote: »

It's only relatively recently that dual brown cables have been introduced for lighting switch drops, it saves having to sleeve the blue to indicate that it's not a neutral

Twin brown cable has been around since at least 2004 and possibly earlier, and previously twin red was available. So it's not a new product.

Also, oversleeving of conductors is not permitted by ET101.

Irish Steve

Risteard81 wrote: »

Twin brown cable has been around since at least 2004 and possibly earlier, and previously twin red was available. So it's not a new product.

Also, oversleeving of conductors is not permitted by ET101.

The first house I rewired was in 1973, so as far as I'm concerned, twin brown with earth wire is relatively new.

ET101 doesn't permit lots of things, but try looking in a lot of Tiger builds, and you may get a surprise or three. Regulations are only worth having if there is a meaningful inspection and enforcement system, which has not been the case in so many areas of construction over the last couple of decades. Probably not worth getting into a rehash of these failings though, it won't change anything, or fix the many shortcuts that were taken in that period.