Green Goo

[m4tty]

Hi,

Was doing testing today before up and coming board change and pulled a cable out of BS3036 clamp and found an oily tar like goo. It had a slight electrical smell.

Whats the score with this stuff. It was on a circuit which I could not trace. It came out of a 15A BS3036 so I thought maybe an old immersion heater as its 2.5/1.0 stranded. Ive left it off to see whether client notices anything not working as I just cannot trace it.

Just wondered if it turns out to be a circuit which ill have to reconnect to new board what to do about the green goo.

Thanks

 

[Zeespark]

I ahve heard that the green goo is down to the DNO equipment Matt, as far as I know you have to put a call in to sort it out. I could be wring about this though, so I would let others back up or discredit My arguement before doing much else.

Andy

 

[Andy™]

its the stuff that keeps the PVC sheath flexible. without it, the PVC goes brittle and can crack if moved. i think there was a thread a few month ago about it

its nothing to do with the DNO (Zeespark - you may be thinking of leaking pitch?)

 

[Brian 157]

"Green Goo" is a known issue with some older cables, "Its origin is the plasticiser used to provide flexibility in the PVC polymer compound. This is generally di-octyl phthalate, which over time or with excessive heat has reacted with the copper conductors to produce copper phthalate (hence the green colour) suspended in the liquid plasticiser. The material is of health concern, so should be handled with care

 

[Zeespark]

Andy is correct I apologise, hence the caveat at the end of the statement.

Andy

 

[Evans Electric]

We have covered it on here but I think Brian 157 has nailed it in his post.

Please note that Brian 157 should not be confused with this Brian :C who would know sod all about the subject, is not the Messiah and is a very naughty boy!!!

 

[revjames]

are you sure its not ectoplasm?

 

[davetheglitz]

My experience is that it can occur with 1960's cables - and it's nasty stuff if you get it on your skin - so be careful.

It doesn't seem to affect insulation resistance much - and seems worse around heat.

In the past I have trimmed back to 'less green' cable and crimped on to the accessories with decent stuff. If this isn't possible I have cleaned up as much as possible with white spirits and insulated/remade as required.

As insulation resistance doesn't seem an issue - it's only contact that I worry about - maybe I should have pushed for the full rewire would have kept the finances up!

 

[kerching]

This was common on cables installed in the 70s. However I have come across this recently on some light fittings installed in the mid 80s...this was slightly 'bluer' than green but I suspect the same stuff. Same cause [ I think ] as when you see plastic Tower clips that seem to have melted onto the cable. Cable is fine underneath but clips have gone really brittle...migration of Plasticiser?? First time I saw it years ago I thought cables were overheating... :coat

 

[sellers]

I'v had something similar but it was more of a cyan.

:coat

 

[gordy71]

I worked at an eccentric american ladies house whose whole house had it running down the walls. She was told by an electrician 20 years ago that it was fairy liquid that was put in the cables to help the electricity run through them better!

 

[ianmacd]

I worked at an eccentric american ladies house whose whole house had it running down the walls. She was told by an electrician 20 years ago that it was fairy liquid that was put in the cables to help the electricity run through them better!

Although thats stupid she may have got the wrong end of the stick as fairy liquid can be useful in helping cables run better in conduit.

 

[Brian 157]

Although thats stupid she may have got the wrong end of the stick as fairy liquid can be useful in helping cables run better in conduit.

You mean I won't get better R1+R2 readings by soaking my cables in fairy liquid first? Damn!

 

[ianmacd]

No but they may feel as soft as your face.

 

[Ash]

Am I right that the old imperial 7/029 3/029 cables have a rating factor when it comes to working on them? Someone mentioned that to me and I never bothered to look into it.

 

[Evans Electric]

What exactly do you mean , Ashers , they have a current rating , obviously, much the same as the metric equivalent , but I suspect you're thinking of something else.

 

[Zeespark]

I think Ash is referring to one of the derating factors for 3036's EE.

Andy

 

[Ash]

What exactly do you mean , Ashers , they have a current rating , obviously, much the same as the metric equivalent , but I suspect you're thinking of something else.

That's probably what the person meant, but nevermind. Would be interested to know where you can find their current ratings though.

 

[ianmacd]

In the downloads section.

 

[pickleye]

Have this in the niceic snags and solutions about green goo, just skimmed thread and looks like its been covered, but here it is on "paper"