Bathroom light switch - can you fix it?

[diydiv]

I've just moved into a Victorian mid terrace and was trying to replace a PIR sensor in the bathroom with a standard 6A 1-way pull cord light switch. The PIR was driving my wife nuts, coming on and going off at every inconvenient time other than when you wanted it on. It drove her so mad, she gave me an ultimatum - either the PIR went or I went. So I was left with no option. The PIR (made in China) had to go. I unscrewed the sensor and had a look at the wires in the ceiling - I can't figure them for the life of me. In one grey cable there is a blue and brown and a single bare wire, which I'm guessing is the earth - fair enough. But, there are also two separate red wires in grey sleeves, which I'm guessing are two live? I took some advice over the phone from our local neighbourhood electrician, who's busy on a job in some other part of the country, and he told me to tape up the blue neutral (which was needed for the sensor), stick the brown into L1/L2 and the two red into Common. I've done exactly what he said and bingo! Nothing. No light when I pull the switch. What have I done wrong? Can anyone help? It's not fun having no light in the bathroom. That old saying "If you sprinkle when you tinkle..." is starting to wear a bit thin... Pics attached to help make thing clearer.

Bathroom light switch ceiling wires

• diydiv
• 17 Jul 2012
• 1

T&E and two single reds. WTF? How did that happen? What is that mess?

The pull cord light switch

• diydiv
• 17 Jul 2012
• 1

6A 1-way. Bought as new from Screwfix. Straight forward, easy peasy - even a child could wire...

 

[Adam_151]

there are no pictures attached

 

[plugwash]

Did you make any notes of how things were wired before disconnecting?
What wires are there at the light and what are they connected to?

 

[333rocky333]

post a pic of the old pir connections, it is possible it never had a neutral connection

 

[diydiv]

The old PIR sensor had three terminal blocks, from left to right - L (arrow down), N, L (arrow up). I'm assuming L is live and N is neutral. Unfortunately, I didn't take a note of which wires went where - big mistake! From memory I'm pretty sure that brown went into L, blue into N and the two red into the other L.

 

[securespark]

Have you tried putting the reds and the brown together?

Having said that, it's no good assuming, but if the colour coding has been used logically, then they should be the line conductors.

You may need a multimeter to test out which conductor is which.

 

[diydiv]

I've uploaded two more pics - shows you the wires to the light and the old PIR sensor blocks.

Bathroom light

• diydiv
• 17 Jul 2012
• 1

Might the problem lie at this end?

PIR sensor

• diydiv
• 17 Jul 2012
• 1

Supposed to sense movement, but seems to have a mind of its own. Made in China on the cheap...

Nope, haven't tried adding the brown to the two red - so should they all go into L2?

 

[securespark]

There ought to be sleeving on the conductors in the light fitting, silicone or glass fibre on the L&N and green/yellow on the CPC.

The LH terminal of the PIR is live feed in and the RH terminal live out. But it's academic, as you can't remember which is which!

I suggested putting the reds & brown together as these should all be line conductors and, this being the case, that should switch the light on, all being well elsewhere in the circuit.

But you really need a multimeter to identify which conductors are which so you know which is the live feed(s). and which is the switch wire(s).

IE, which wire goes to common and which to L1. Not that it matters on a one way switch, as long as you don't put switch and feed wires in the same terminals, then you'll get lights that are permanently on.

 

[diydiv]

Thanks securespark, that's really useful. It sounds like a job for a qualified electrician, since I don't have a multimeter. Can I just confirm though - are you suggesting I put all three wires (brown and two reds) into common? I could try that and if that fails put all three into L1 - eventually I'll get there by trial and error. What do you think? And how about taping up the neutral - was that sound advice?

 

[ban-all-sheds]

That old saying "If you sprinkle when you tinkle..." is starting to wear a bit thin

Well tell your wife that until the light is working she'll have to sit down.

 

[EFLImpudence]

either the PIR went or I went.

There is another option.

 

[diydiv]

So, anyway, where have we got to with this? If you were the electrician faced with this task and you didn't have your multimeter on you, what would you do next?

 

[slup]

Have you done what was suggested and put the red and brown wires into the same terminal (leaving the blue one taped up)?

 

[ban-all-sheds]

If you were the electrician faced with this task and you didn't have your multimeter on you, what would you do next?

Go out to the van and get it.

 

[plugwash]

Go into the loft and see where the wires were going.