Mattayscough said:
I am swapping over to a new switch and the two wires going into the one gang switch are both red.
One gang switch? Post topic is "
Two gang switch wiring probs"??
From my celing rose I have deduced that I have a junction box circuit. Surely there should be one cable with a red and black wire each going into the switch?
That's the usual way of doing it..
It looks as though whoever wired it up has run 2 cables from the junction box and used the live wires to run the current to the switch and just clamped the neutral wires to the switch box?
With lighting circuits it's very important to not automatically make the red=live black=neutral associations, because as you point out, the normal way of doing it ends up with the black being switched live.
And the blacks should not be connected to the switch box, unless they are connected to the earth of the lighting circuit,
and they are sleeved green/yellow at both ends.
Does anyone have any idea whay they may have used 2 live wires rather than a live and a neutral?
They didn't use 2 live instead of live and neutral - they used 2 red instead of red & black.
I am aware that a neutral wire from a swith will still carry live current.
Then it's not a neutral, is it?
Sorry to labour the point, but it is a very important one, and getting it wrong at ceiling roses (i.e. thinking that all the blacks are neutral) is the commonest mistake people make, and it leads to blown/tripped fuses/MCBs and wrecked switches...
Perhaps the person used 2 red wires to prevent him from having to label the nutral from the switch with red tape?
He may have used 2 red wires because he didn't realise that it was common practice to use the black for switched live. Seems a lot of effort to go to just to avoid having to sleeve the black.
You are sure, are you that the blacks are
not really neutrals, i.e. someone has taken live & neutral to the switch, and switched live and neutral from the switch to the light, and has been stupid enough to use the box earth terminal to join the neutrals instead of choc-block?
Is there an earth wire in the cables? Are they connected to anything?