Can anyone point me in the direction of some current information
relating to the phenomenon of Green Goo (di-isoctyl phthalate) from
For those who are not familiar, it is a green substance which oozes
from electrical fittings and caused by reaction of PVC compound used
in cables from mid 1960's to early 70's.
I'm looking for something authoritative - I believe there used to be
something by NICEIC, but I can't seem to find anything on their site
The following statements were attributed to the IEE or NICEIC by the
people who posted them:-
Attributed to NICEIC:-
"Green goo is a phenomena sometimes encountered in electrical
installations constructed in the late 1960s.
Unsightly green slime can occur in switch and socket-outlet boxes. It
is understood that this phenomenon is most prevalent where pvc cables
manufactured between 1965 and 1971 have been used.
The green slime, or green goo, is degraded di-isoctyl phthalate and
is considered to result from a chemical reaction between the
plasticiser of the insulation and the copper conductor in the pvc
cable. Between 1965 and 1971 the temperature performance of pvc was
uprated by the inclusion of an anti-oxidant into the pvc compound. An
unappreciated side effect was that the anti-oxidant encouraged
production of the exudate.
There is evidence to suggest that high ambient temperatures
accelerate the process. The exudate is of low flammability and low
toxicity. Although unsightly, it does not reduce the electrical
integrity of the conductor or the insulation. However, the exudate
may have detrimental effects on both accessories (in appearance and
functionality terms) and their surrounding decorative finishes."
Attributed to IEE:-
"It is most prevalent in cables made between 1965 and 1971. The gunge
is degraded di-isoctyl phthalate and is the result of the reaction
between the plasticiser in the insulation and the copper. Between
1965 and 1971 the temperature performance of PVC was uprated by the
inclusion of an anti-oxidant in to the PVC. An unappreciated side
effect was that the anti-oxidant encouraged the production of
Evidence suggests that high ambient temperatures accelerate the
process. The exudate is of low flammability and low toxicity.
Although unsightly it does not reduce the electrical integrity of the
conductor or the insulation.
Green exudate from PVC
Draft BCA statement (April 2001)
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
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.
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."
Take your pick :-)
That's from an article in a thread in the IEE/IET wiring regs forum,
rather than from the institution itself. The whole thread is here:
OTOH the NICEIC seem to have removed almost all the useful content from
their Web site, presumably in the name of marketing.
I thought that was a little too advanced for the chaps..
Any acid will produce various other salts from the basic oxides.
Carbonate is green, sulphate is blue..can't remember what color acetate
is and copper chloride/chlorate is soluble IIRC and washes off..
One of the most useful metals when playing the 'maximum number of
colored stripes in a test tube, using what's in the chem lab' game ...
Thanks for all the replies.
I'm a bit concerned about that Australian link though ..... especially
after reading the disclaimer, which amongst other things says -
"The department makes no statements, representations, or warranties
about the accuracy or completeness of, and you should not rely on, any
information contained on this site"
lol. What is the point of puting it there then?
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