DIY Doctor UK DIY Forums

DOWN STAIRES CLOCKROOM,HALL AND FRONT ROOM LIGHTS DONOT WORK .LIVE SUPPLY IS PRESENT BUT NEUTRAL NOT.HAVE CHECKED PULL CORD SWITCH AND OUTHER TWO SWITCHES.ON OPENING THE WALL SWITCHES I FOUND BOTH TERMINALS WERE COVERED WITH GREEN STICKY STUFF.BOTH TERMINALS SHOWED LIVE WITH PHASE TESTER WHETHER SWITCH WAS ON OR OFF.AS SWITCHES WERE NOT REMOVED BEFORE AND NO SIGN OF TEMPERING I AM PUZZLED AS TO HOW THIS COULD HAVE HAPPENED.HOPPING MY PROBLEM WILL BE SOLVED I CHANGED SWITCHES.THOUGH BOTH SWITCHES STARTED FUNCTIONING LIGHTS ARE NOT COMING.THE PULL CORD SWITCH WAS ALSO NOT FUCTIONING WHEN CONNECTED AND POWER SWITCHED ON I.E.BLACK LEAD TERMINAL SHOULD INDICATE PHASE LEADING TO CELING ROSE.REMOVING THE BLACK LEAD FROM THE SWITCH AND CHECKING THE TERMINAL SHOWED SWITCHING FUNCTION.I BELIEVE THESE LIGHTS ARE END OF THE CIRCUIT AND THERFORE SUSPECT LOOSE CONNECTION SOMEWHERE.COULD PREVIOUS WATER INGRESS CREAT SUCH PROBLEM(BATHROOM IS ABOVE).THOUGH EVERYTHING IS DRY NOW .SUPPLY IS FED FROM LOUNG AND ALL LIGHTS ARE WORIKING.

This an article I found which may help your understanding of your findings.

Re: Green smelly liquid from sockets
Posted: Nov 5, 2003 12:19 PM Reply


Something I dug up from my files:

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.

A bit technical but answers the question.

Also try this link; https://www.diydoctor.org.uk/projects/re ... itting.htm

KB