Lampholder Isolator Information Guide.
The Lampholder isolator is a small plastic tube like item that sits in the bottom of the lampholder.
Its main function is to ensure that when wiring of the lampholder you have 2 layers of insulation between the copper cable and the item the lampholder is sat on top of.
When you go to strip the cable to connect it into the lampholder you need to ensure that the outer PVC jacket is stripped back to the base of the lampholder as shown in this image below.
That's the first hurdle complete but when you connect the center part of the lampholder and push it down the cable is going to slide backwards out of the base of the lampholder.
This means that the blue and brown cables "Could" now be resting inside the metal pipe the lampholder is sitting on top of, this means there is now only 1 layer of insulation between the copper cable and the metal pipe.
So this is where the isolator comes into play, as the isolator is plastic it counts as 1 layer of insulation.
This image below shows this, its hard to see but inside the plastic tube (isolator) you can see the blue and brown cables.
That is the position you need to aim for, If however you have this, see below image....
Then this is wrong because the isolator is not giving you 2 layers of insulation.
This does not apply if you are using a 2 core cable with non exposed metal parts.
i.e. A plastic threaded lampholder on top of a plastic threaded fixing base on top of a wooden lamp base.