Wiring a replacement PIR lamp with permanent live.

[Alex A]

I wish to replace a PIR lamp which has failed. When removing the old lamp, there were five wires 2 live, 2 neutral and an earth. However the two lives were connected outside the lamp terminals. Is this safe and, if so, how should the two neutrals be connected ?

Thanks.
.

 

[ProDave]

You understanding is wrong and could lead to you doing something dangerous.

You might have two brown and two blue wires (or even old red and black wires) but you do NOT nave two live and two neutral. One pair will be live and neutral feeding the light fitting and the other pair will be the drop to the light switch so one will be permanent live and the other switched live.

If done properly the switched live will have been sleeved to indicate it's function. Often it is not.

So without some testing you could very well end up with a dangerous situation.

Post some pictures as it is now BEFORE you disconnect anything for more advice.

 

[Alex A]

You understanding is wrong and could lead to you doing something dangerous.

You might have two brown and two blue wires (or even old red and black wires) but you do NOT nave two live and two neutral. One pair will be live and neutral feeding the light fitting and the other pair will be the drop to the light switch so one will be permanent live and the other switched live.

If done properly the switched live will have been sleeved to indicate it's function. Often it is not.

So without some testing you could very well end up with a dangerous situation.

Post some pictures as it is now BEFORE you disconnect anything for more advice.

You understanding is wrong and could lead to you doing something dangerous.

You might have two brown and two blue wires (or even old red and black wires) but you do NOT nave two live and two neutral. One pair will be live and neutral feeding the light fitting and the other pair will be the drop to the light switch so one will be permanent live and the other switched live.

If done properly the switched live will have been sleeved to indicate it's function. Often it is not.

So without some testing you could very well end up with a dangerous situation.

Post some pictures as it is now BEFORE you disconnect anything for more advice.

You understanding is wrong and could lead to you doing something dangerous.

You might have two brown and two blue wires (or even old red and black wires) but you do NOT nave two live and two neutral. One pair will be live and neutral feeding the light fitting and the other pair will be the drop to the light switch so one will be permanent live and the other switched live.

If done properly the switched live will have been sleeved to indicate it's function. Often it is not.

So without some testing you could very well end up with a dangerous situation.

Post some pictures as it is now BEFORE you disconnect anything for more advice.

Here’s a photo of the wires - none sleeved.

 

[ProDave]

So now you have created a problem, that you don't know which pair is the live and neutral feed, and which pair is the probable switch drop.

We try to tell people to take pictures and identify each core somehow BEFORE disconnecting anything but it falls on deaf ears.

Most PIR lamps these days come with a flying lead, so your first job will be to fix a waterproof junction box to the wall to terminate those cables, and then when you have identified which is which you can terminate them and then connect your new light.

 

[kerching]

God put cameras on phones for two main reasons
1) taking pics BEFORE altering anything
2) other stuff

 

[SPECIAL LOCATION]

I wish to replace a PIR lamp which has failed. When removing the old lamp, there were five wires 2 live, 2 neutral and an earth. However the two lives were connected outside the lamp terminals. Is this safe and, if so, how should the two neutrals be connected ?

Thanks.
.

Look closely at your photo there are two earth wires in that bit of green yellow sleeve.
So you have two standard Twin & Earth cables.

One cable is probably Red (live) and Black (neutral) + earth supply from the consumer unit, or previous light in the circuit...
The other cable is probably Red (live) and Black (Switched live) + earth to/from the manual light switch..

So one of blacks, the proper supply neutral, should go onto the neutral of the new light fitting...
And the switched live Black, (which should have had a red sleeve or tape around it), will go onto the live of the new light fiting..

And as it was previously the two reds should be connected together in a separate terminal..
to take the live supply to the switch, but not connected to the lamp, otherwise you will not be able to turn the light off..

Unless it is a class 2 Double insulated light fitting, then the two earths should be securely terminated into the earth terminal on the light.. If it is Class 2 then they should be left connected to each other in a suitable terminal connector.

If you attempted to just joint the two reds and two blacks together into the live & neutral terminals of the light..
When the switch was turned off, the light would be permanently on..
And if you turned the switch on it would directly short out the supply, tripping the fuse and possibly welding the switch contacts together..

So you need to do some dead testing to identify exactly which cable is which, and do not attempt random connections and just putting the power back on to see if it works!!

 

[Alex A]

Look closely at your photo there are two earth wires in that bit of green yellow sleeve.
So you have two standard Twin & Earth cables.

One cable is probably Red (live) and Black (neutral) + earth supply from the consumer unit, or previous light in the circuit...
The other cable is probably Red (live) and Black (Switched live) + earth to/from the manual light switch..

So one of blacks, the proper supply neutral, should go onto the neutral of the new light fitting...
And the switched live Black, (which should have had a red sleeve or tape around it), will go onto the live of the new light fiting..

And as it was previously the two reds should be connected together in a separate terminal..
to take the live supply to the switch, but not connected to the lamp, otherwise you will not be able to turn the light off..

Unless it is a class 2 Double insulated light fitting, then the two earths should be securely terminated into the earth terminal on the light.. If it is Class 2 then they should be left connected to each other in a suitable terminal connector.

If you attempted to just joint the two reds and two blacks together into the live & neutral terminals of the light..
When the switch was turned off, the light would be permanently on..
And if you turned the switch on it would directly short out the supply, tripping the fuse and possibly welding the switch contacts together..

So you need to do some dead testing to identify exactly which cable is which, and do not attempt random connections and just putting the power back on to see if it works!!

Thank you, very clear and extremely helpful!