two way lighting in a flat

[hoodie786]

hello guys
i just bough a flat and one of the two way light switch wasnt working so i opend them both up and each switch had three wires one red and two blacks on switch one the common is live and that same common goes to switch two and the two blacks at each switch are in the same terminal ie l1 to l1 so on but at switch two there is a switch with two switches one fir the two way light that works fine but another red cable just one red cable that feeds another passage light but it has no permanent live in the common terminal is there any way to find permanent live in switch two because if i turn off switch one it cuts all the power to switch two so u cant fnd a permanent live the cables are consuit cables mounted in trunking

thanks guys[/quote]

 

[ericmark]

I can't quite follow what you are saying if you look at the diagram

you will see there is a line to both switches the bottom outer connection. It was at one time common borrow this line from a second switch in a pair so only two wires were required between switches.

However this causes two problems first is interference mains hum can be transmitted to radios for example and the second is where the lighting circuit has been split i.e. up stairs and down stairs it can cause a borrowed neutral situation.

Where RCD's have been fitted the electrician has two options either he breaks the rules and puts both lighting circuits on the same RCD or he disconnects the two way system. If he puts both on same RCD it should also be the same circuit breaker so as to prevent a borrowed neutral situation where the silly 50W spots have been used this can mean a 6A MCB is overloaded and since the ceiling roses are only rated at 6A putting a larger MCB is not an option.

As to if your house has these problems I don't know but it is clearly not quite as easy as just borrowing a line from another switch you do need to check how wired first.

 

[winston1]

hello guys
i just bough a flat and one of the two way light switch wasnt working so i opend them both up and each switch had three wires one red and two blacks on switch one the common is live and that same common goes to switch two and the two blacks at each switch are in the same terminal ie l1 to l1 so on but at switch two there is a switch with two switches one fir the two way light that works fine but another red cable just one red cable that feeds another passage light but it has no permanent live in the common terminal is there any way to find permanent live in switch two because if i turn off switch one it cuts all the power to switch two so u cant fnd a permanent live the cables are consuit cables mounted in trunking

thanks guys

[/quote

Could you re write that with a bit of punctuation so we can understand it.

 

[phatboy]

Could you re write that with a bit of punctuation so we can understand it.

Agreed, I got lost about 2 lines in. If you punctuate it properly we can help you more easily

 

[hoodie786]

sorry guysp