Green electric sticky stuff

[talltree]

Hi
Every time I undo a light switch or fitting I find this green sticky stuff oozing out of the wires. Is this cause for concern? Our house was built in 1968. I'd be grateful for any opinions.

 

[SparkyTris]

Sounds like condensed electricity!!

Seriously, though:

could the green ooze be copper-related? (ie, is it similar in shade to the green that you might see on an old copper coin that has been outside for a while?)
if so, then the wiring might be admitting water at some point which is certainly a cause for concern.

Or is the green ooze more plasticcy-related? if its's sticky, then it could be something leaching out of the insulation. However, unless you have green-coloured cables, there should be no green to leach out.


green sludge in the wiring or switches is a very common problem on older ships where seawater gets into a cable. water can travel for enormous distances (even uphill) along a cable once it gets in.

 

[breezer]

are the cables in steel pipes ? (conduit)

it may be washing up liquid put in to make cable pulling easier.

but at 1968, time for a rewire

 

[Lectrician]

Have seen this on a property - just as you say. I put it down to the fact that there was a fire in the house, and that it could be due to that and the water for extinguishing.

Only saw it when I changed a light switch for a neighbour, the switch had worn out, and I put this down to water aswell. I told them to get a PIR done on the property, as I was only changing the switch as a favour.

 

[supersparks]

its a plasticiser additive i cant remember the name of.
they added it as an experiment in the mid -late 60s(also comes back for about a year at some point in the 70s), its very common with alu cable aswell arround the time of the copper shortage.

not anything to be immediatly concerned about, but you WILL need a rewire in the next 10 years, keep your eye on it

 

[ban-all-sheds]

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.

See http://www.screwfix.com/talk/thread.jspa?threadID=314

 

[pipme]

From NZ ! :- http://www.olex.co.nz/faq_general.php

What is Green Slime or Goo? And do I need to re-wire circuits with Green Slime coming out of the wires?

Also known as "Green Slime", this phenomenon is characterised by the appearance of a sticky green exudate leaking out of PVC-insulated wiring at locations such as switches, hot points and light fittings. The green goo problem is predominantly associated with older (25+ years) TPS-type cables operating in a warm environment. The exudate comprises a plasticiser that has migrated out of the PVC insulation, coloured due to reaction with the copper conductor.

Due to its stickiness and unsightly colour, the goo has a high nuisance value, however it poses no significant health hazard. It may be cleaned from surfaces by wiping with a rag soaked in a petroleum- or alcohol-based solvent (such as meths).

The long-term consequence of the exudate is that it represents a de-plasticising of the insulation, meaning that as the process continues the PVC will eventually become brittle, and crack.

P

 

[Lectrician]

........after a long period of time for some cables, or if the cable has been severely overheated.
The plasticiser itself is a clear........

May explain why it happened after a fire in the property I saw it in, as all the neighbouring properties, including mine are fine!