2way light problem

[jab64000]

Hi can anyone tell me what the problem is with my hall light?
I have a 2 way light for my hall lights, one switch (2g2w)at the front door and another at the other end of the hall (1g2w)
I had a problem with the light switch at the front door when the old light switch broke internally and would not operate my lights. I bought a new (2g2w) switch and changed it out. I was very careful to put it back just as it was but now the switch at the front door will not operate the lights unless the switch down the hall is switched on? I checked both switches and have the live connected to the com in both switches and then 1 wire each going to bothe the L1 and L2 on both switches. All the wires are red!
Can anyone enlighten me as to what has gone wrong? I have tried changing the strappers round but it isn’t making any difference so I put it back as it was. For info - The 2nd gang on the switch at my front door has a link from the com side of the switch that isn’t working to the com side of the outdoor Gang and it seems to be working normally?
Thanks in advance

 

[EFLImpudence]

As the wires are all red then it will be impossible for us to tell.

How many wires run between the two switches?

Perhaps pictures of both switches may help.

 

[jab64000]

3 wires between each of the switches. It’s an old house so single wires have been run in conduit. Assuming the neutrals are connected on the ceiling Rose?

 

[EFLImpudence]

If you have three wires between the switches then the same wire must be connected to COM at both, the other two Between L1s and L2s don't matter.

Plus at one of the switches there should be a permanent live from the supply also in L1 and a switched live to the light also in L2.

 

[ban-all-sheds]

My guess is that the new switch has the terminals laid out in a different way to the old one, and you've got things mixed up between one gang and another.

As they are all one colour, you're going to need to identify which is which. Please don't carry on trying different connections hoping to luck onto the one that works - trial-and-error guesswork is a daft basis for doing electrical work.

You basically have to choose between Plan A and Plan B.

PLAN A:

• Learn how lighting circuits are wired.
  • //www.diynot.com/wiki/Electrics:Lighting
  • http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Lighting
  • http://www.google.co.uk/search?q=uk+lighting+wiring+(basics+OR+101)
  • //www.diynot.com/wiki/Electrics:books
  • //www.diynot.com/wiki/Electrics:index
• Get a multimeter and learn how to use it.
• Identify which conductors are which at the switches and the light positions.
• Work out what should go where and connect everything up properly.

PLAN B:

• Get an electrician.

 

[ericmark]

I checked both switches and have the live connected to the com in both switches

If you look at EFLImpudence diagram you will note permanent line is not connected to com. As long as you get the com wire which is only connected to the two com's of the two two way switches, and nothing else connected, then getting L1 or L2 wrong will not stop switch from working it will just mean both switches up, may not be off. Com is permanent line with simple on/off, but not with two way.

 

[bernardgreen]

Com is permanent line with simple on/off, but not with two way.

It can be wired as

The advantage with EFLImpendance's method is that there is permanent Live at both switches.

With a single way circuit putting Live into L1 and cinnecting Com to the lamp avoids the L2 terminal ( if there ) from becoming Live when the lamp is OFF

 

[ban-all-sheds]

.. avoids the L2 terminal ( if there ) from becoming Live when the lamp is OFF

Why is that desirable?

 

[bernardgreen]

Why is that desirable?

One less Live terminal to worry about, 99.9% of meddling with switches it will have no actual benefit but 1 shock in 1000 incidents of meddling with switches could be said to be one shock too many.

 

[ban-all-sheds]

Assuming the circuit has been left on, please provide diagrams of how to wire 1-way, 2-way, and intermediate switches such that there are no terminals with live conductors in them when the light is off.

 

[bernardgreen]

I said "one less" not "none at all"

 

[ban-all-sheds]

Pointless, then.

 

[JohnW2]

... getting L1 or L2 wrong will not stop switch from working it will just mean both switches up, may not be off.

True (and equally true that both switches down may not be off). However, that is of very little practical consequence in normal use, since someone looking at one switch will usually have no idea as to the position of the other one.

Kind Regards, John

 

[EFLImpudence]

Also with this method, an extra connector is required.

The OP may one day return but at the moment we don't even know which switch (at which end of the diagram) he is working on.

There is no mention of additional L/SL wires, merely -
"I checked both switches and have the live connected to the com in both switches and then 1 wire each going to bothe the L1 and L2 on both switches."
that live will, of course, depend on the position of the switch - at one end at least.

 

[JohnW2]

Also with this method, an extra connector is required.

View attachment 148441

Indeed. Certainly in the past, and undoubtedly sometimes now, some may be tempted to avoid that, and also to remove the need for a 3-core cable, by doing ...

That has at least two problems. Firstly, the lack of paired L/N conductors in the cables introduces potential EMC issues. Secondly, particularly in the common situation of hall/landing switches, it also introduces a relatively high temptation to use L and N from different circuits ('borrowed neutral' or 'borrowed line'), with the problems and potential risks that can introduce.

Kind Regards, John