Is this VIR

[studentspark]

Black twin and earth with 250V Grade printed on it.

Outer insulation seems like PVC and stable, no cracking or breaking, have not seen inner cores.

Not sure, any thoughts
Thanks

View media item 78693

 

[DaftPunk]

It's rubber cable.

 

[securespark]

Yes, it looks like it.

Often these cables only degrade at termination points or where subject to extremes of temperature, especially at luminaires.

 

[RF Lighting]

I was brought up to know cloth covered waxed singles as often found in 1930s slip joint conduit as VIR, and the cable as per the OP as rubber insulated cable, but I've seen folk on here refer to that as VIR!

Don't know what the right answer is here.

 

[Adam_151]

I think a distinction is being drawn where there isn't one.

VIR is vulcanised india rubber, i.e. Natural rubber that has undergone the process of vulcanisation to change its properties (less sticky, more durable, etc)

Both types of cable are made with vulcanised rubber, therefore they can both be called VIR (or rubber cable if your wish)

I don't believe you can have a cable insulated with non vulcanised rubber, it would be unusable I recon

These days the term TRS (tough rubber sheath) is used for rubber flexes etc, however I don't believe its anything other then VIR, although these days there are probably additives / improvements to the pprocess to improve live span.

I did find a large house wired in the early 70's with PVC cabling, but TRS flex had been used between the isolators and the oven and the hob, and these were crumbling just as the old 1950s vir/rubber did

 

[JohnW2]

VIR is vulcanised india rubber, i.e. Natural rubber that has undergone the process of vulcanisation to change its properties (less sticky, more durable, etc) ... Both types of cable are made with vulcanised rubber, therefore they can both be called VIR (or rubber cable if your wish) ... I don't believe you can have a cable insulated with non vulcanised rubber, it would be unusable I recon ... These days the term TRS (tough rubber sheath) is used for rubber flexes etc, however I don't believe its anything other then VIR, although these days there are probably additives / improvements to the pprocess to improve live span.

Yes, but, as you say, you are talking about (vulcanised) natural rubber. The synthetic rubbers which are now used for cable insulation (e.g. butyl, silicone, EPR, PCP rubbers etc.) are a totally different kettle of fish - and I don't think they suffer from the type of degradation for which VIR is famous.

Kind Regards, John