Green liquid

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• 19 Oct 2005

• #1

Hi

Been doing a little work on the electrics in a 1960 built house with original wiring, PVC type insulation, and have noticed on some sockets and light switchs there is a green liquid which appears to be originating from bewteen the conductors and their sleeving.

I assume its green as its been in contact with the copper wire.

Whats likely to be causing this ? Seems rather strange to me.

 

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plugwash

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• 19 Oct 2005

• #2

its a know issue with some old pvc cables to do with the plasticiser.

it comes out more often if such cables are overloaded but it will sometimes come out without such provocation.

its not immediately dangerous but it would be a good idea to keep an eye on the cables insulation resistance etc.

 

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• 19 Oct 2005

• #3

Thats a relief don't need to wear the welly boots as isulation when walking around the house then

Thanks

 

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Adam_151

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• 19 Oct 2005

• #4

Make sure you wash your hands after touching it before eating, can cause slight illness otherwise

 

ban-all-sheds

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• 20 Oct 2005

• #5

It's di-octyl phthalate.

Green exudate from PVC

Draft BCA statement (April 2001)


1) PVC

PVC comes in two main grades, plasticised and unplasticised PVC.

Unplasticised PVC (UPVC) is used for example in double glazing window frames where a rigid material is required.

The PVC used for manufacture of cables is a plasticised PVC that conforms to the relevant British Standard for the cable type in question.

2) Ageing effects

As a cable ages (at temperatures above normal ambient) the elongation to break decreases (also the Insulation Resistance increases). The life expectancy of a cable is arbitrarily considered to be when the elongation to break of the PVC is 50%.
A lower elongation to break value could be considered suitable especially for a fixed wiring cable. Therefore, providing the cable is not subject to movement or when moved due to inspection of socket outlet or the like, the PVC does not crack, a much lower value of elongation to break is considered by some as suitable.

3) Greening

Greening is the appearance of a wet green substance that is a product of an adverse reaction between certain types of plasticiser and the copper conductors. This greening, which is a rare occurrence, can happen either after a long period of time for some cables, or if the cable has been severely overheated.
The plasticiser itself is a clear oily liquid that is non conductive. The green substance is a combination of copper oxide and plasticiser which may become conductive under certain adverse conditions.

4) Action if Greening is found

Therefore whenever this green substance is found at socket outlets etc. initially it should be removed and the terminations cleaned (gloves should be used) otherwise it is possible that tracking/overheating may occur. It is strongly recommended that rewiring should be carried out as soon as possible.

If further information is required, the original cable manufacturer should be contacted.