NOS Plessey caps brown one end white the other

[Luxman1050]

Can anyone tell me why these plessy caps have a brown end and white end? Is it to do with the white end going towards lowest resistance point or don't matter which way round they go?

The dark end probably marks the outer foil, it doesn't matter much.

[dazzlevision]

They look like a post TCC/Plessey-TCC branding metal cased paper dielectric capacitor, so could well be rather leaky.

[G6Tanuki]

Yes they do look like a revamp of the old TCC Metalpack/Metalmite-style. I wouldn't trust them any further than I could spit a rat.

[ColinTheAmpMan1]

Originally Posted by cdm1christopher

Can anyone tell me why these plessy caps have a brown end and white end? Is it to do with the white end going towards lowest resistance point or don't matter which way round they go?

There is a pretty good way of telling which is the outer foil if you have a scope. Hold the cap without touching either lead and then connect each lead in turn to the scope input. The biggest noise signal will be shown when the outer foil is connected to the scope. Squeezing the capacitor will increase the noise pick-up, too.

As for leakage, the only sure solution is to use an insulation tester and select the voltage that is the working voltage of the capacitor. If it looks good, try the next highest voltage that you can apply.

Good Luck.

[Luxman1050]

Don't have a scope so not an option there reading highish but within their 20% +/-. I was gonna use them for ceramics but prob not best option so gone for Metallised polypropylene.
Plenty of gear to refurb so could whack in there see what happens don't like to bin stuff without giving it a go prob plenty on here who the same.
Cheers