exterior wall light with hard wiring new build property

[biggurs]

Hi

Newbie on this forum so I would like to wish everyone a happy christmas and a happy new year.

I have recently moved into a new build property made by persimmon homes. I want to install an exterior wall light, there is already hard wiring for this.

When I uncovered the small box housing the wiring I discovered there are FOUR wires.

Three wires which are brown, blue and earth and an additional brown one (which is thinner than the rest of the three)

But the exterior light i want to install has only 3 wires (brown, blue and earth)

So to which three do i connect to??

I assume, using logic, that I will connect blue to blue, earth to earth, brown to brown (ashes to ashes if i'm not careful!!!!!!!)

and leave the thinner brown (odd one) unconnected (it wont be 'unconnected', it will remain connected to the plastic block which all the wires are connected to, which i presume is the connector)

I would be grateful if someone can help me out on this one, otherwise I will have to just wait until after christmas to contact the site manager.

Many thanks in advance

 

[spinlondon]

I think you will do better to wait and speak to the site manager.

It may be that they intended the wiring for a specific light fitting, which your light might not be compatible with.

It might be that with the 3 wires connected, the 4th wire might be a switch wire from a PIR or other controller?

Or it could be that the light fitting was intended to have an integral PIR, and the 4th wire is to connect to an alarm, or other lights?

 

[batty]

Welcome to the forum Biggurs as spin says this is more involved than just putting a light up. You will need a test meter to see which wire is live and which is switched. even an electrician would take a while to work out how this was wired.

Batty

 

[biggurs]

cheers.

The light i intend to fit has a PIR sensor.

Its the type that stays on from dusk till dawn and increases in brightness as someone approaches the doorway.

It has the three usual wires but the wiring inthe wall has four.

The chap across the road noticed me looking abit confused and said he had the same problem and had to contact the site manager who had to 'sort it out'

I just thought it was a money making scheme cos the house builder wanted about

 

[Lurch]

Knowing Persimmon the 'extra' wire will be connected to the street lights, or the house across the road.

 

[Apache]

Hello, welcome and a Merry Christmas to you too!

Do you have a basic multimeter? Are you able to measure voltage and continuity (does it buzz when you touch the leads together in a certian setting?)

A picture of the set up may help!

Did any of your neighbours chose to have the lights fitted? Could you have a look (and take a picture) of one of theirs wired up?

Do you just have 1 box to wire an outside light too, or are there more than one? If multiple the extra could be to link PIRs?

 

[Dane]

If in doubt

get a spark that's my advice. although it will cost you.

You say its simple, it obviously isnt if ure unsure.

More details would be great though

get your tester out and test...

Perm live, switch live etc etc

 

[Andy™]

complete guess here, but id go with the seperate brown being a switched live from light switch, the the T&E being perm live/neutral/earth

 

[spinlondon]

The main problem with this, is it is not a normal set up.

If there had been 3 wires, or 5 then it would be simple.

As there are 4 wires, it doesn't confom to any normal set up.

It could be as simple as just connecting the wires as per your first post, and forgetting about the 4th wire. However, I would like to know the purpose of the 4th wire. I would also like to know if there is a switch somewhere to turn this light on and off.

 

[Dane]

The main problem with this, is it is not a normal set up.

Whats not normal about having a perm live and switch live? (does depend if there is a switch though)

 

[spinlondon]

Whats not normal about having a perm live and switch live? (does depend if there is a switch though)

You tell me?

 

[Andy™]

You tell me?

fairly simple. light may be controlled from inside via switch. in which case it needs a sw. live. or it may be self controlled via PIR. in which case it needs perm live.

they may have just installed wiring to easily accept both types of light

although it would have been easier taking the T&E / flex to the loop in point, and the light can be connected to either perm or sw. live as required

 

[matt.leung]

do you require how to go about the issues of working out what cable is what, in other words which is the sl and the per live feed???

 

[spinlondon]

I wonder why the 4th wire is thinner than the others?

I would expect even a light controlled by a PIR to have an on off switch.

Perhaps one is to feed the PIR, and the other is for the light?

If there were just 3 wires, I'd think that they had taken the feed to the switch and then a switched live to the light. If there were 5 wires, I'd think they'd taken the feed to the light, and the other 2 wires were the feed to the switch and the switched live.

Some systems use a master PIR light, that will tell slave lights to switch on when activated, and require a link to do this.

Some lights have outputs to connect a link to an alarm or camera system.

I believe that there is even a fitting with 2 lamps, one permanently light incandescant and the other a halogen flood connected to a PIR.

However as I suggested in my first post, I believe it would be best to wait and ask the site manager. Might even be able to obtain a wiring diagram.

 

[Dane]

When the OP is saying "thinner" hes not exactly said what is thinner, T and E is obviously not as thin as a single core.

If its the cores.

Then a picture would be great to help others see what could be going off here.

How much "thinner" also would help. Not easy to tell though when you don't work with it regularly.

 

[Andy™]

may be that one feed is 1.5, the other is 1

 

[Lurch]

I think this is getting a bit out of hand. As a bunch of electricians we can all say 'it's easy, you just connect it up' but (and no offence to the OP) if he can;t do it and doesn;t feel confident then he should get someone else to do it rather than prodding about trying to let us guess what might be going on.

 

[ProDave]

I would put my money on one brown being a permanent live, and the other brown being a switched live, from a switch inside the house near the front door.

You should be able to determine which switch that is, as currently, without an outside light fitted, one switch will apparently do nothing at the moment.

So inside your PIR light fitting, you will usually find terminal marked L N and E. N and E are obvious. L will be intended for a permanent feed, so connect one of your brown wires to that.

The other brown wire will go to a possibly unlabelled terminal that links the output of the inbuilt PIR sensor to the light.

Then turn it on and try it. The light switch inside should override the sensor and turn the light on any time of day or night. With the light switch off, the light should trigger, only at night, from it's internal PIR sensor.

If it doesn't operate like that, reverse the 2 brown wires and try again (if they are the wrong way round, the light will never turn off)

That all assumes you don't have a meter to measure which one is permanent and which one is switched.

Oh and one rather important point, don't forget to turn all the electric off at the consumer unit before fitting the light.

Regarding builders and rip off charges for extras. I fitted some extra sockets in a new build where the buyer had only the bare minimum number of 13A sockets. The builder wanted to charge

 

[biggurs]

Hi

The blue, brown and earth wires are the same thickness and the the fourth wire which is also brown is of thinner diameter than the rest of the other three.

It is this one which appears to be the odd one out, but must be there for a reason.

I do not have any testing equipment.

Someone mentioned something about a switch..... there IS a switch in the hallway which is for the exterior light.

I will try and get a pic done soon but am away for a while.

I will try and contact the site manager tomorrow (providing he is not on x-mas hols)

Thanks again

 

[Dane]

if there is a switch and the switch is in the OFF position and light still works via a PIR/Dusk-dawn

then the second brown will be a switch live.

If you have no testing equipment and are unsure.

Get an electrician in to do the job! Might cost you a few quid, but its done correctly and safely then!