double switch

[lee1317]

my mate has got new brass switches for his house his dad has done all the single ones but cant do the doubles. ive had a look today and iam well confused the new switch has 6 connectors 2 at the top which are (com),and 4 at the bottom which are 1-2 and 1-2. the old switch has 3 at the top and 3 at the bottom, the top ones from left to right are com1 yellow wire,(3) yellow wire and (2) blue wire. the bottom ones in the same order are (3) no wire,(2) two red wires and (1com) with 1 red wire.
ive tried some combo's today but it either tripped the breaker or the light could only be controled with that switch and not the one up stairs.
can anyone shed some light please. the house is only 4 years old if this helps. all wires are twin and earth the earths are conected to the back box and the yellows are defo yellow not yellow/green.
cheers

 

[Adam_151]

all wires are twin and earth

Where do the yellows and blues come from then?

You sure you haven't got any 3 core and earths in there, actaully what cables do you have to have three reds, two yellows and a blue?

A diagram might not go amiss...

 

[lee1317]

not sure m8. i'll have to have another look thursday it could have been 3 core and earth it's the yellows that are throwing me not seen them before. the other double in the kitchen has no yellows or blue just red black and earth

 

[JohnD]

new switch has 6 connectors 2 at the top which are (com),and 4 at the bottom which are 1-2 and 1-2. the old switch has 3 at the top and 3 at the bottom

The new double switches have a total of 6 terminals, so did the old ones. Each two-way switch has 3. The only difference is that the new switch has both commons at the top, and the old one had the com for one switch at the top, and one at the bott.

I'm guessing your mate didn't make a note of the wiring conections before he undid the old switches

 

[Adam_151]

if we are talking pre-harmonised colours (which we are), then twin and earth has red and black, and 3c + earth has red, blue, and yellow, there is no set way in which 3c + earth is used really, there are a few standard arrangments for two way switching etc (but even then it varies what colour is used for what), its a case of working out what each core has been used for in most cases.

a photo or diagram would be a big help

oh, and if you picture the new switch as two triangles, with the coms forming the top point of each one, now imagine turning one of the triangles through 180, thats how your existing switch is layed out

 

[lee1317]

adam that make's sense now about the triangles ive just looked at the diagram ive done and think ive sussed it now i will try again tomorow cheers everyone. great site this by the way

 

[securespark]

Never mind that.....

There is no reason (unless there are neutrals at the switch posn or a short has been introduced) that the breaker should trip if you mix up the wiring.