PVC twin & earth & water

[jedisparks]

Evenin all

Just a bit of an odd ball question here following a discussion i had today.

PVC twin & earth - If it is exposed to moisture or is laying in water over a long period of time, can this have a deteriorating effect on the cable sheath

Many thanks

 

[MarkieSparkie]

Evenin all

Just a bit of an odd ball question here following a discussion i had today.

PVC twin & earth - If it is exposed to moisture or is laying in water over a long period of time, can this have a deteriorating effect on the cable sheath

Many thanks

Hi jedi, The water will not have a deteriorating effect on the PVC material, however, the PVC insulation of T&E and other cable is not totally impervious to water penetration (GN1, 4.5) and some water will be absorbed over time, the deeper the cable is submerged in water the faster the rate of penetration. Where water resistance is required polyethylene or polythene (PE) is used for the insulation material, on telecoms, data transmission, and instrumentation cables. When PE is cross-linked (XLPE) to improve it's thermal propeties it becomes suitable for power cable applications eg. XLPE SWA cables.
For use in extreme situations the cable manufacturers make sub-marine cables, with extra thick insulation for pressure resistance.
Generally, exposure to moisture does not lead to water penetration. Even continuous exposure to a few inches of water will take months for penetration in my experience, but given sufficient time it will happen.

 

[oxocube]

PVC cables are not suitable for continuous immersion in water.

 

[truckster]

None at all in my opinion

Even the water industry use pvc for piping because of its unpenetrability,(that was a nicely made up word)

Not sure if applies to PVC, but I've known women with the condition!

 

[Rappid]

Interesting. But could that have been down to exposure to sun rather than water?

It was quite an old cable, cores was red and black

 

[Engineer54]

Standard Building wire insulation is in fact microporos, not sure about the sheath on T&E. It will let minuet traces of water through the PVC over a period of time. The deeper the cable/wire is submersed then obviously the higher the pressure on the microporos covering, letting more water to pass through.


Not all PVC is the same, the cable makers use different additives and enhancers to suit the grade and type of covering required. There is indeed totally impervious to water PVC coverings, but it isn't your standard building wires/cables. Sheathing by the way, is a totally different PVC make-up to insulation PVC.

 

[jedisparks]

Which one?

The guy