Outside light mystery

[Graeme Barry]

Hello, new member here with little elec knowledge and a mystery regarding our outside light. Our house is quite old and the wiring is, shall we say, non-standard. We replaced the old light a few weeks ago. It worked fine but was old. There was an indoor switch for it just inside the back door.

When I removed the old light it had 2 live red wires and 2 neutral blue wires going into an old 2-part wiring block in the light. So, unless I'm mistaken, there were two red wires going into the same hole in the wiring block and a single red one coming out into the bulb fitting. Same for neutral. I think the two yellow earth were unconnected.

I tried connecting both live, both neutral and both earth into the new light. When I turned the mains back on the bulb lit up but it would not go off when I switched the indoor switch on and off. The switch had worked fine on the previous light. So we had the bulb permanently on unless we just unscrewed the bulb.

Thinking the two wires meant there were two switches, we tried all the other indoor switches but with no success.

Then, thinking that perhaps 3 of the wires came straight from the mains with no switch, we tried detaching one of the live and one of the neutrals in different combinations. We found that the light only went one with one of the pairs of live and neutral - let's call them Live A and Neutral A. Both B wires, or either A/B combos failed to light the bulb.

On paper it seems the switch is the problem but it worked fine with the old light and we haven't touched it.

Any suggestions? Many thanks!

 

[Toneyz]

Did you not take a photo or got a diagram of what the original wiring was to the old light. Also, did the old light have a pir?

 

[Deleted member 26818]

Sounds like one pair of wires is the live feed, and the other pair the switch feed.
I would have expected the live from the live feed to be made off in a connector block along with one of the switch feed wires.
Then the other switch feed wire connected into the live terminal on the light.

 

[Pete999]

Get hold of Mr Sparky to help, faffing around with combinations of wires and switches will end up in total confusion, a sparky with test equipment should sort it out in about 10 minutes, you know I'm right.

 

[Toneyz]

Is this not a three core and earth cable with the yellow over sleeved with red as you state red cables and blue cables. Without some sort of visual help, it is just guest work.

 

[Graeme Barry]

No and no

Sounds like one pair of wires is the live feed, and the other pair the switch feed.
I would have expected the live from the live feed to be made off in a connector block along with one of the switch feed wires.
Then the other switch feed wire connected into the live terminal on the light.

Hi SpinLondon,
Sorry to be slow, what colour wires from which the switch feed go where? The red into the live terminal on the light and the blue goes...where?

 

[Deleted member 26818]

Is this not a three core and earth cable with the yellow over sleeved with red as you state red cables and blue cables. Without some sort of visual help, it is just guest work.

Sounds like it’s wired in 3 core.
2 reds, 2 blues and 2 yellows.

 

[ipf]

No and no

Hi SpinLondon,
Sorry to be slow, what colour wires from which the switch feed go where? The red into the live terminal on the light and the blue goes...where?

Expecting a bit of transcendental meditation and mind reading, I feel.

Get someone qualified to sort it......on site.

 

[telectrix]

if Oakhill is the one i think of in Stoke-on-Trent, I may be over there Saturday. if so, I can call and have a shufty.

 

[Graeme Barry]

Sounds like it’s wired in 3 core.
2 reds, 2 blues and 2 yellows.

Yes, that's right

 

[Deleted member 26818]

No and no

Hi SpinLondon,
Sorry to be slow, what colour wires from which the switch feed go where? The red into the live terminal on the light and the blue goes...where?

Sorry, forum rules don’t allow me to tell you which wire terminates where.

 

[Graeme Barry]

Sorry, forum rules don’t allow me to tell you which wire terminates where.

Oh okay, that makes sense. Thank you anyway! I think my sister has just sent a diagram which matched your explanation.

 

[telectrix]

red to red, yellow to yellow, blue to bits. .

 

[Graeme Barry]

No

if Oakhill is the one i think of in Stoke-on-Trent, I may be over there Saturday. if so, I can call and have a shufty.

No, Oakhill Somerset, but thank you

 

[Toneyz]

Sorry, forum rules don’t allow me to tell you which wire terminates where.

You can only assume red is P/L yellow is SW and blue is neutral but without some basic test equipment, it would be only an assumption.

 

[James]

This time,
Get a local spark in, it should take him 10 min from start do finish.
Next time,
Take a picture or make notes of what goes where BEFORE you take down the old light.

 

[ipf]

You can only assume red is P/L yellow is SW and blue is neutral but without some basic test equipment, it would be only an assumption.

Yep. Assume or presume?......stick a pin in it, either way.

red to red, yellow to yellow, blue to bits. .

.....as said...….

 

[Deleted member 9648]

I do love these, "I've connected the new light exactly the same as the old and it worked before....."

 

[Toneyz]

I do love these, "I've connected the new light exactly the same as the old and it worked before....."

That's why I asked if the existing was a PIR light that had a permanent live and neutral and the yellow S/L in a terminal block also some photo's would have helped.

 

[ipf]

I do love these, "I've connected the new light exactly the same as the old and it worked before....."

Aye, it's a doddle...….until