Green Colour seeping from light switch

[LaughALot]

Does anyone know the reason for Green Colour seeping from light switch. This seeping colour is actually coming from the wires behind the switch, and running down the wall.

This is only coming from where the wires are connected to the switch. I believe the wiring is around 30 years old, not original house wiring. This is a 1933 semi-detached house.

My guess is that the wires are getting overheated and you get the colour coming off as a result.

Any budding Electricians out there. Any suggestions would be useful.

[raysparx1]

It sounds more like damp seeping from somewhere, are the wires sort of slimey when you touch them, ? if it is coming from the wire it could be "Verdigris" (spelling) which comes from copper, the first thing to do is to check the switch it could be overheating, I doubt very much there is anything wrong with the wire itself, if it is PVC 30 years is nothing in terms of life span for this type of cable, nobody could say for certain how long PVC cable will last, but certainly a lot longer than 30 years, if you are worried about it get a local sparky to check it, good luck, Ray

[markja]

laughalot, turn the electric off before you check if the wires are slimey !! if you don't you'll not be chuckeling again.

[RATTER15]

I think you have a little alien living in your switch, the light is his way of communicating with the Mothership!! beware!!!

[jno]

this is quite common when there is a dead body decomposing in the wall. Often people are sacrificed when the house is being built, to placate the gods of the borough council.

[goodlooking]

The affected cables are PVC insulated and sheathed only
The substance is the plasticiser used in the manufacture of the cable during the 60s. The release of the substance is initiated and exacerbated by high ambient temperatures such as that found in ceiling spaces. The substance is not conductive and therefore not liable to electrical tracking.
The presence of this substance will not alter the flame propagation characteristics of the cable, nor does it necessitate the replacement of the cable.

Cables should be assessed for replacement only when insulation tests reveal failure or when cracking of the insulation becomes apparent.
This green exudate is mildly toxic and can cause burning and irritation, especially to mucous membranes such as in the eyes, nose and mouth, however there has been no epidemiological link established with cancer in humans.

The substance is not water soluble and should be removed from hands using an oil solvent type of cleanser. Methylated spirits is a suitable solvent for cleaning the substance from switch plates etc. Caution: do not use excessive amounts of methylated spirits as it could create a fire hazard. Power to any electrical equipment and sockets must be isolated and the methylated spirits should be applied using a dampened cloth.
In some cases, such as behind light switches or socket outlets, the amount of exudate can be reduced by forming a drip loop in the cables below the terminal