Bank Holiday 2 Way Light Switch!!

[333rocky333]

I personally would remove the bulbs from the offending rooms , you are picking up now, or proberly will pick up readings through or from the neutrals

 

[333rocky333]

Forget the screwdriver they are unreliable.
Answering some of the past questions may help you further

Spacecat and others have suggested what may be what including the red link.
Without the answers you are not giving who knows.

The multimeter is no help if you do not know how to use it, and the readings you posted are misleading.

Again you did not answer what they meant and is the reason we are struggling to assist.

When you said "fused the electrics", without explanation when asked may be the reason people are now refraining from helping, for your own safety.
sorry.

 

[DIYerHELP]

Managed to get home from work in daylight today and tried Spacecat's approach. Now working! I was confusing which cable was the two way cable due to the old switch layout compared with the new one. Lesson learn't I think!

Just like to thank all that have replied.

 

[Space cat]

Would the permanent live be the red wire with the strapper (link) as this is the only one that lights the neon electrical screwdriver?

That was certainly my first thought, especially since it is consistent with the number of wires available and the function of the switches but ---

Red with Strapper (link) : 24v : 24v

Unless you had the power off when you measured this, something is not quite right. As you have probably realized from those voltage measurements, a multimeter isn't the answer to all your problems. All I can offer at the moment is more questions:

1) You cannot light a real neon with 24V. Is your 'neon' screwdriver a real one or is it one of those gadgets with a battery and a LED inside which can also be used for testing fuses? Those things are good for fuse testing but not much else.

2) Way back at the beginning of this post, you said you measured 12V on that red wire with the extra link attached. How exactly did you measure this?

3) When you "fused the electrics" was this the lights only or most of the house? How did you reset it?

Meanwhile, I would suggest that "Overload" on your meter means that you are on the wrong range. If the meter only goes up to 200 volts, Overload is what you will get if you try to measure 230 volts with it!

The symmetry in the readings from the left hand cable is interesting and suggests that this really is the cable for the two-way switch - and that my first guess was correct - but there's a problem. Why do you have only 24 volts on the red wire with link? The rather ominous possibility is that your live and neutral are reversed.

Edit: I've just read you latest post and it's nice to know that it all works again but the question still remains; why only 24V? Unless you can explain this anomaly, there may still be something wrong in there.

 

[securespark]

Trouble is, do you really want to trust your electrics to an extra-terrestrial feline?

It would seem the answer is YES!

 

[333rocky333]

1) You cannot light a real neon with 24V.

I dont have a neon , but with one of them ones with about 4 neons on, i think the first lit neon, is marked 12v although it proberly is not .
I think it would light one neon if you touched a N or a neutral bar with it.

Hopefully it was off when tested
I reckon if so he may be picking up , some voltage from the Neutral bar feeding back through the other room lamps, if the switches were in on position, they would put that slight voltage on the circuit live rail , including the red link ,due to the mcb being off.
Anyway you sorted it ,well done

 

[Space cat]

DIYerHELP, are you still there? It isn't really sorted until those anomalous meter readings have been explained. When you measured the voltages on the switch wires, where did you put the other meter prod? Did you put it on the earth terminal in the back box?

I can think of two reasons why you might get those voltage readings and neither of them is good:

1) Live and neutral are crossed over.

2) Your back box is live!

You say that the only wire that would light your neon was the red link. Did you try the earth wires? If they are live then something is seriously wrong and it might not be limited to that switch. Try your neon driver on the fixing screws in other switches - and also on any metal parts of light fittings.

 

[DIYerHELP]

Hi Space Cat,

Still here! Yes, I put the other prod on the earth terminal in the back box to get those readings. I didn't try the earth wire with the neon.

Cheers.

 

[Space cat]

I didn't try the earth wire with the neon.

DO IT SOON!!!

If the fixing screws are metal you won't need to take the switch off the wall. Just test a screw. Do it with power on.

 

[DIYerHELP]

Tested the screws - no reading. To be sure thou I took the plate off. Again no reading on just the earth wires with the neon.

 

[Space cat]

Tested the screws - no reading. To be sure thou I took the plate off. Again no reading on just the earth wires with the neon.

Well that's a good start but it's a pity you didn't check the other terminals while you were in there. This is what you should have found:

1) Earth wires/back box - always dead (= neon out).

2) Red wire with link - always live (= neon lit).

3) Other wire in one-way switch - live if the light is on, otherwise dead.

4) Other wires in two-way switch - at least one is live but it changes when you flip the switch.

In (4) the status of the third (non-live) wire may depend upon whether or not the light is on. If it's off, the third wire should be dead but, if it's on, you might get a dim glow from a neon driver. That's because, in the circuit you obviously have, the third wire is floating (both ends disconnected) when the light is on and a floating wire can have enough capacitive coupling to adjacent live wires to light a neon.

If you feel like going back in to check all this, try your meter as well and see if you can make sense of what it's telling you.

PS: You still haven't told us how you measured 12V on the red wire.