New Exterior Light But Spare Cables Remain After Fitting Ask questions and find answers to many subjects relating to electrics and electrical work

[Pheme]

I recently replaced an exterior light. The cable in the wall was connected to a plastic block with the following four connections

1. two red wires
2. one red and one black wire
3. two black wires
4. three yellow/green wires

My new light had a small block with two white cables; one connected to live and one connected to neutral and one yellow/green connected to earth (the block had been handily marked)

Because I didn't know what to do (or indeed what they are for) with the spare wires (ie. the two red ones) within the electrical cable from the wall I was forced to use the existing block.

I connected one of the (light's) white cables (neutral) to the two black cables in the block. I connected the other white cable (live) to the red and black and obviously the yellow/green to yellow/green.

The light works fine, but the block is so big it doesn't fit snugly behind the cavity between the wall light and the wall. Whilst it won't fall off, it's not as secure as I would wish - and then I suppose there's a chance of water seeping in. Of course I will see if I can get a smaller block with four connections, but wondered why the 'spare' wires and whether there is another alternative.

The light switch is on the internal wall (it is a double-switch that also turns the kitchen lights on/off). The light that I took off had no sensor - nor has the one I put on.

Thank you.

PS. Please do not assume (I'm sure you guessed that from my post) I know anything about electrics in any reply. I don't.

[proptech]

Hi Pheme

It sounds like you have correctly wired the light, but I'm concerned that by what you say, rainwater could enter, causing a danger.
Perhaps you could post a photo or two.

Could there be, or have been another outside light on the same switch ? That would explain the wiring you describe.

As I say I'd be more concerned if anything is exposed, or not designed for external use.

[Pheme]

Proptech

Thank you for your response. Unfortunately, the light and I are in separate locations right now, but will take some this evening, although I doubt whether it will show up the problem clearly.

I am probably being over-cautious. However, I feel as though I haven't done the job properly. I had to switch the existing screws that fix the light onto its backplate on the wall with longer ones so that I could put the external bolts on. The light is not wobbly, but it's not firm either. There is a rubber washer between the backplate and the light in which the cables are housed, but I'm still worried. I know I could use some sealant around it, but I see that as a bit of a bodge.

The previous exterior light pre-dated my arrival at the property about ten years ago. However, what I did not mention (and never even thought about until I read your comment) is that there is another exterior light on the side wall (the one I've just replaced is on the back wall). The bulb has died in it and I cannot remove the rusted screw on the glass dome to replace it (but I'm working on it).. The internal switch will turn both exterior lights on at once. Is that why I have those extra wires? What are they for?

Thank you.

[ericmark]

Standard wiring to a ceiling rose is power in - power out to next light - wires to switch.

This means there is always power to the ceiling rose which is handy for emergency lights and ceiling fans and it also reduces the cable run to each lamp so reduces the earth loop impedance reading.

Other countries use the switch as a junction box not the ceiling rose so often lamps designed for Europe don't have provision for extra cables.

With outside lamps we normally follow Europe type wiring often using a switched fused connection unit so should it get water in the lamp we can isolate it so it will not trip any RCD. Some times just a double pole switch is used, but out side lights we tend to switch the neutral but we don't with inside lighting.

It would seem your outside light is wired like an inside lamp.

As to rain one of the problems with any light is they get hot and as they cool they can suck in water. It is near impossible to seal them so instead we leave a small hole in bottom for water to run out.

[Pheme]

Thank you epicmark.

So should I worry that my outside light is wired like an inside one? Those extra (red) wires need to be connected to the block?

I cannot see a small hole on the base of the light for drainage.

I have been to the DIY store and I see those plastic blocks are sold in longer sections that you can break down. They appear to be smaller than the one that is on the light fitting now, so it may enable me to get the light more flush with the wall.

You can see in the picture that the light is leaning forward (red arrow).

[ericmark]

Can't see picture this site has always had problems with pictures I have given up trying.

I would not think there would be a problem using a smaller size connector block but clearly I am not on site so I can't be 100%.

[Pheme]

Thank you. I hadn't realised the plastic blocks were sold depending on the amps. I'm going to stick with the current block but look for shorter screws to fix the light onto the backplate (which in turn is secured to the wall). This, I hope, will make the light more stable.