Install light switch homeless earth cable

[jfhandel]

Yes, it's very loosely sleeved. The light is only controlled by the single switch. In all likelihood the installation was originally completed when the house was built c. 1995. Not sure if that makes it more or less likely to have been botched

 

[bernardgreen]

As there is only one switch for the lamp then it almost certainly is not a strapper ( live ) and is an earth.

So terminate it as advised in a bit of terminal strip and not in any of the terminals on the switch.

 

[JohnW2]

Yes, it's very loosely sleeved. The light is only controlled by the single switch. In all likelihood the installation was originally completed when the house was built c. 1995. Not sure if that makes it more or less likely to have been botched

I fear that botching started in the year dot and will remain with us for evermore!

If there isn't a second switch, I suspect the most likely explanation is that the wire in question really is an earth wire, and that you and the person who originally did the wiring (who, seriously wrongly, may have used the 'spare terminal' of the switch as a parking place for the earth wire) were both lucky in connecting the two browns the way around that didn't result in a bang! However, I think you probably do need an electrician to ascertain exactly what is going on. In the meantime, do as EFLI has suggested and get that 'earth wire' out of harm's way, totally covered by the G/Y sleeving.

Kind Regards, John

 

[jfhandel]

OK, so firstly a big thank you to all of you, not least as you responded so quickly.

Although revealing a new level numpty-ism on my part, I'm pleased to report that this has turned out better than I had expected. At your prompting I went back into the switch to sort the errant earth wire, only to find that there WAS after all an earth block attached to the backplate of the switch. I'd been so busy trying to find it on the 'front plate' where the switch and terminals were located I'd completely overlooked it!

So the earth wire has a proper home at last!

That said, it does raise the spectre of why it had been arranged as it had in the first place, so I may still get a professional to run some checks.

Thanks once again for your help


JFH

 

[JohnW2]

Although revealing a new level numpty-ism on my part, I'm pleased to report that this has turned out better than I had expected. At your prompting I went back into the switch to sort the errant earth wire, only to find that there WAS after all an earth block attached to the backplate of the switch. I'd been so busy trying to find it on the 'front plate' where the switch and terminals were located I'd completely overlooked it! .... So the earth wire has a proper home at last! ... That said, it does raise the spectre of why it had been arranged as it had in the first place, so I may still get a professional to run some checks.

Glad that you have found at least an immediate solution!

It does sound as if it probably really is an 'earth wire' and that someone very stupidly 'parked' it in what appeared to be a 'spare' terminal of the switch. In case you're interested, I'll try to explain why that is so potentially dangerous....

... a two way switch connects 'COM' to either L1 or L2, according to whether the switch is in the 'on' or 'off' position. The switch never connects L1 to L2.

To work as a light switch, the switch is placed between the live feed and the light (i.e. your two browns). If the live feed were connected to L1 or L2, and the light to COM, then the live feed would never be connected by the switch to the other of the 'L' terminals (L2 or L1), so nothing terrible would happen if one connected that 'spare' L terminal to earth. However, if the live feed were connected to COM (and the light to one of the Ls), in one position of the switch the live feed (COM) would be connected to the other ('spare') L terminal - so if that terminal were connected to earth, you would then have a connection between live and earth - hence a bang!

Hope that makes some sense.

Kind Regards, John

 

[jfhandel]

Thank you John for that very clear explanation, if only the supplied instructions had been so clear.

BTW is it critical for live feed to be connected to Com and the light to either L1 or L2? Or can the live go into L1 or 2 and the light into Com?

 

[Aragorn84]

BTW is it critical for live feed to be connected to Com and the light to either L1 or L2? Or can the live go into L1 or 2 and the light into Com?

For 1 way switching it doesnt matter.

For 2 way switching, like a hallway light with two switches, they need to be in the correct places.

 

[JohnW2]

Thank you John for that very clear explanation, if only the supplied instructions had been so clear.

You're welcome.

BTW is it critical for live feed to be connected to Com and the light to either L1 or L2? Or can the live go into L1 or 2 and the light into Com?

As you have just been told, for 'one-way switching' (i.e. if only one switch controls the light), it makes no difference. If it were a wall switch, rather than a pull one, the choice between L1 and L2 would determine 'which way up' the switch worked (i.e. whether 'up=off' or 'up=on'). Some people work to a convention of always connecting the live feed to COM - which is, of course, the option that could have caused a bang when you had the earth connected to the switch!

Kind Regards, John

 

[securespark]

I don't think a pull switch will have a back-box.

Ah - you have a point there, at least in the case of a pull switch for a light

Kind Regards, John

These have back boxes:

Or you could flush-mount the above with the following:

I have seen this before.

I have also seen the pull cords flush-mounted on these before:

 

[bernardgreen]

For 1 way switching it doesnt matter.

Putting Live into L1 and Switched Live into COM has the minor advantage that the un-used L2 terminal does not become live when the switch is OFF ( but this could confuse the average house basher aka cable installler )

 

[JohnW2]

Putting Live into L1 and Switched Live into COM has the minor advantage that the un-used L2 terminal does not become live when the switch is OFF ( but this could confuse the average house basher aka cable installler )

Indeed - that is, of course, the very point I explained in detail to the OP. If the 'earth wire' really is an earth, the only reason why there was no bang was that, by pure chance, the Live was not connected to COM. However, as I also said, I know that some deliberately adopt the convention of connecting permanent live to COM.

Having said that, when (as with the OP) the conductors are both brown, I very much doubt that many electricians would dream of bothering to identify 'which was which'! Even when the conductors are brown/blue (or red/black), conventions don't seem consistent. I have personally always used the over-sleeved one (blue or black) as the switched live, but I know that others adopt the opposite convention (if any!).

Kinf Regards, John