Attack Of The Green Slime

A few months ago, I built myself a new server and from the outset it had that smell of new electronics breaking in. But the smell never went away. Not a burning smell, more like electrolytic caps. I'm always alert for scorching odour.

Today I needed to open up the system and unplugged its power cord and was surprised to find green slime on the contacts. Admittedly I mated a new power supply with a cord that is probably 10-15 years old.

It has a slight dimple on one face which makes the lettering appear curved in the photo.

IEC plug with strange green goop

Any idea what caused this?



The green-ness is a dead giveaway that this is one or more copper compounds, from corrosion of the contacts inside and/or the metal of the pins in the IEC socket.

Many copper compounds are green. The "verdigris" that makes the Statue of Liberty green, for instance, is primarily copper (II) carbonate. In the case of your goopy power plug, the wetness of the goop means that if the computer isn't sitting under a roof leak, there must be a hygroscopic (water-attracting) compound in there. That rules out copper carbonate, but there are several other copper compounds that'll suck water out of the air to one degree or another.

I think this process can be self-accelerating - a tiny bit of the hygroscopic compound is formed, it sucks up some water which dampens the area and accelerates the corrosion, and in the case of an electrical contact may further accelerate the reaction by increasing resistance so the area warms up. It's the warm copper compounds and/or plastic that's making the funny smell. It's also possible that outgassing from the plastic of the plug on the back of the new computer, or degeneration of the plastic in the old cord, has contributed to the reaction. Cable insulation is normally made from PVC, which stands for polyvinyl chloride, and every link in the PVC chain has a chlorine atom just waiting to be liberated, so I wouldn't be at all surprised if there was copper(II) chloride in the slime.

You can see similar green compounds discolouring the edges of copper or copper-alloy fittings in clothing, like riveted jeans or brass belt buckles. The copper compounds form a sticky goop there that's probably based on clothing fibres, sweat and shed skin flakes, all coloured (and flavoured!) by the copper compounds. (I presume hipsters who never wash their jeans develop particularly impressive rings of green goop.)

Fortunately, none of this is a big problem. Just discard the old IEC lead, make sure the pins inside the plug are clean (a pen eraser should be adequate to remove any tarnish), and plug in a new lead.

14 Responses to “Attack Of The Green Slime”

  1. moller Says:

    Read a scroll of fire or cast cure sickness.

  2. TwoHedWlf Says:

    Your computer has swine flu and it's gotten snot all over the lead.

  3. Red October Says:

    Never seen that happen before, and I've got IEC power cords from probably the earliest equipment to use them.

  4. Alex Whiteside Says:

    Clearly he is being accosted by an evil Vulcan spirit trying to scare him out of his home. I'm not sure whether the Catholic Church or the Scientologists are the safer bet.

  5. RichVR Says:

    Mint jelly?

  6. Red October Says:

    If he aims to find out by licking it, I'd advise he disconnect the other end beforehand...

  7. corinoco Says:

    Black cable rot.

    People of a certain age, who may have been avid RC car builders in the mid-eighties (how I wish I still had my Tamiya Superchamp, they're worth a fortune now) know, and fear the dreaded black cable rot.

    It always happened in the black (negative) cable, so the theories were either electolytic or chemical outgassing from black vinyl only. I think a blend of the two. I know some oils would do it too.

    A very left-field reason comes from the building trades - I'm currently working on a building with 1,200 sqm of glorious copper roof, and UREA is used to rapidly give it the verdigris look. Cue the stories of lining up the builders at the end of the day with half a slab of VB each, and they aren't allowed to go home until all is emptied.

  8. Daniel Rutter Says:

    Victoria Bitter, a popular Australian beer.

    (I note that Google currently ranks Visual Basic one above Victoria Bitter in a search for VB, and AcronymFinder puts Posh Spice two steps higher.)

  9. dazzawul Says:

    Excuse my ignorance, but why are they tipping out cants of VB in front of the builders? :S

  10. dr_w00t Says:

    I'm not sure if the medium of text is masking sarcasm in your comment or not but here we go anyway.

    Verdigris is the green coating on copper buildins (anything copper), and is apparently a desireable look for buildings with copper roofing. Apparently, urea can be used as a catalyst/solvent/reagent (don't know which) to achieve the verdigris effect. Urine contains urea (and possibly a bunch of other stuff which may actually be the cause of the verdigris rather than urea specifically). As Dan pointed out above, VB is an Australian Beer, the thirst for which you can get it fuckin a cow... matter of fact I'm fuckin one now. Finally, alcohol, as we all well know, is an antidiuretic hormone inhibitor.

    So to summarise, the builders would line up, drink half a slab each and piss all over the roof to make it go green!

  11. dr_w00t Says:

    I'm not sure if the OP was pissing on his 240v power cables or not though. :)

  12. dazzawul Says:

    oooh, no I wasnt being sarcastic, it just didnt click.

    For some reason I thought someone had taken a piss while up the roof cause they didnt want to get down from there, and cause noone would own up they wasted beer (the achillies heel of a tradie, if you will :P) in front of everyone?

    it was 2 am! my mind works funny! but thanks for the explaination :)

Leave a Reply