Fluorescent lamp - flickering while off.

[CortinaV8]

Thought this was a bit odd.

Switched off the above light in the kitchen, but the tube was still faintly flickering as if it was pulsing between one end of the tube to the other.

Switched the downstairs lighting MCB and it still continued to flicker.

Switch to the light is switched via the live.

I did notice that the ballast/choke was very hot to touch and seems to have leaked some sort of tar, is it fair to say whatever the ballast was potted in has broken down and is causing the problem or should I be looking elsewhere, I am going to lift the boards and have a look at the wiring above, however all the other lights on the same circuit seem to be working fine.

 

[Space cat]

There are really only two possibilities:

1) The hidden capacitor strikes again. If the cable feeding the light is lying alongside other cables on a different circuit, a ring main perhaps, enough current could leak through this unseen capacitor to make your tube flicker. You can test this very easily by turning off other circuits at the CU.

2) There's a lot of RF energy flying around! Do you live near overhead power lines? What about TV/radio transmitters?

A fluorescent light fitting should have a capacitor fitted across its live and neutral terminals. This is intended to reduce interference coming out into the wiring and also to improve the power factor but, as a side benefit, it will go a long way towards eliminating unwanted leakage effects by shunting the current away to neutral. Maybe yours is faulty or missing.