by northstream » Wed Feb 28, 2018 6:27 pm
by ericmark » Thu Mar 01, 2018 11:50 am
by northstream » Fri Mar 02, 2018 1:01 pm
by northstream » Fri Mar 02, 2018 8:01 pm
ericmark wrote:Hot is an American term it does not apply in this country as we don’t have delta supplies with one winding centre tapped.
Since the neutral as well as the phase wire is considered as live, with single phase we call the phase wire line.
Nothing stops us using blue as a line wire, however we should over sleeve with brown when we do. However the brown sleeve often falls off or has been missed, I have tried to explain in the past how to test without a meter, however it is so easy to make a mistake, the result can be shocking, so really only safe was is with a bell and battery or meter, (that is why we still call it belling out a circuit) the meter often has a built in buzzer and battery so step one is to identify the cables.
The switch wire is normally quite easy, especially with two people, one working light switch the other testing the cables to find which goes to the switch, once that wire is identified, really what is left does not really matter, simple brown to brown and blue to blue (or bits if you get it wrong) only where there are two roses controlled by one lamp do you need to go further.
First switch will have one twin and earth and one triple and earth. The twin and earth does not connect to common with two way switching, and triple and earth is like for like between two way switches.
Using non electronic switches if more than two then an intermediate switch/s is used between the first and last switch and the wire which connects to common does not connect to intermediate switch. With electronic switches the common does not exist as such, it becomes a trigger wire, and you don’t use intermediate switches, but master and slaves.
As to central heating rather than lights, each switch only turns it on, not off, all wired in parallel, switch (room thermostat) turns it on, the TRV turns it off. So nothing like two way lights.