On 07/01/17 13:27, Fredxxx wrote:
I've been asked to look at some old Christmas tree lights.

I am confident this will be the of the direct mains type with single
insulated twisted pair and probably conforming to BS 4647:1970.

I am aware new mains lights of this type would have additional
insulation as per BS EN 60335.

Obviously I can only do a visual inspection on them, but what is the
current thinking of single insulated mains cable in terms of PAT or
equivalent testing?

They would be noted as "Class 0".

The safest course of action would be to fail them as it's not really a
big problem to replace with a modern set.