Cable discolouration

[highspark]

Is this an indicator that cables are overheating/first sign of deterioration?

Called out to a youth centre all upstairs lights out. Located fault a a flourescent fitting. Neutrals completely burnt out with no insulation left. I've isolated fitting. IR's are testing fine now. However I'm noticing discolouration inside the fittings of most of conductors. I am suspecting over time the insulation is going to become brittle and break away leaving exposed conductors.

Time for a rewire of circuit?

 

[Guitarist]

Wow, what did the 'little girl' have up there? A heat lamp for the cannabis plants .......

The family had just moved in. Immaculate house, but a few DIY light installs by the previous owners. It was a bathroom style enclosed metal fitting rated at 60w per side, but with 80w lamps in. Whoever fitted it had trapped the 3 T&E's between that fitting and the wooden noggin, which you can see was very charred and had actually been smouldering away.
If the owner hadn't asked me to change it, I have no doubt whatsoever that the whole place would have gone up in flames.