2 way switches

[Anthonydx]

I have a light in the hall that was controlled by a switch there and on the upstairs landing. The switches were old bakerlite ones with black and red wiring, they were swapped for new ones but now the light only works when the upstairs switch is in the on position whereas it used to work both ways. I am stuck on how to rewire it, I have looked through the stickies but still not sure. Wires with no switches connected are

Downstairs-
Black is 12v
Red is 12v
Blk/Red is 0 twisted together

Upstairs
Red is 12v
Black is 12v
Red is 12v

So what goes where, switches both have
1 way
2 way
Common

Can anyone explain?

 

[Johnmelad502]

12v ????

Can you post some pictures?

Do you have a multimeter?

 

[electronicsuk]

Downstairs-
Black is 12v
Red is 12v
Blk/Red is 0 twisted together

Upstairs
Red is 12v
Black is 12v
Red is 12v

So what goes where, switches both have
1 way
2 way
Common

I'm very suspect of those measurements, and equally suspect about the whole idea of changing out old bakelite switches for new ones when the wiring is probably hopelessly out of date.

My best guess would be that the reds on the upstairs should be going to the 1/2 way terminals and black to com, then blk/red on the downstairs switch to com with the remaining two wires to 1/2 way. However, it is nothing more than a guess. I assume you didn't keep a note of how the old switches were wired?

 

[Anthonydx]

I have a mains voltage tester, looking at it again the number was quite long and started with 12 I gues I should read the last three where it says 220?

 

[EdwardCurrent]

Hello,
Is this a 'double decker' caravan/boat ?

How are you measuring this 12volts please ?

Ed

Sorry.
Have you looked in the 'wiki' at the wiring diagrams, they may be of some help. //www.diynot.com/wiki/electrics:lighting:two_way_lighting
Good Luck
Ed

 

[electronicsuk]

I have a mains voltage tester, looking at it again the number was quite long and started with 12 I gues I should read the last three where it says 220?

The trouble is, it sounds like you have a multimeter, and while a very useful tool in any electrician's kit, they have a very high input impedance when measuring voltage and do have a tendency to display 'ghost' readings from capacitive coupling and the like. For this sort of testing you would be better off with a two piece voltage indicator, something like a Steinel Multi Check, Fluke T50, etc. These contain neon lamps or LEDs and a dummy load, and will avoid the aforementioned pitfalls of multimeters.

I would also be interested to know what you are using as a ground reference. Presumably a local earth connection? If the wiring is old then it shouldn't be assumed that one is even present.

 

[Anthonydx]

No earth at all, just the red and black wires, the meter was a B&Q one that you put to the wire and push a button to test for live.

 

[Johnmelad502]

No earth at all, just the red and black wires, the meter was a B&Q one that you put to the wire and push a button to test for live.

Pictures please...

 

[reggie perrin]

Does it ever cross anybody else's mind that sometimes there are posts on this forum from other sites looking to test DIYnot and trying to have a laugh?

 

[Taylortwocities]

Does it ever cross anybody else's mind that sometimes there are posts on this forum from other sites looking to test DIYnot and trying to have a laugh?

Yes, its called "trolling". Very boring it is too.

Yes pictures would be good.
Anthony - did you make a note of where the wires went on the old switches?
What are the terminals called on the old switches, C, L1 and L2??

These new switches. Are they plastic, or metal?