polystyrene beads and electrical cable twin and earth

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Ah! that would explain why the average Pole tries to wire a lighting cicuit like a ring!!
Did you do the survey of common domestic wiring systems in Poland yourself? Are the results published anywhere?

If you're relying on other data, could you point us at it?
 
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Thanks 'sheds'. I unreservedly apologise for my comments and prepraszam (yes I can pronounce it - I had a Polish wife and travelled extensively in Poland!) to our Polish friends and colleagues. Funny enough 'cowboys' is the same in both languages! It's just I had another of these dodgy jobs at the end of a long day... new wiring, both a safety and fire hazard. Bathroom lighting: special location? Who cares?! Down-lighters? no problem... we'll cover them with newspaper so the light doesn't shine through the cracks in the newly sanded floorboards in your child's bedroom above...
Sorry if I snapped, but it's it's the 4th or 5th potentially lethal job I've had to redo in as many weeks.
"Actually, yes! They WERE Polish! Ha! Ha!" (The client)
 
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Crikey was it something I said? I've been trying hard to understand your trails of thought but I must confess I got lost at about the Darwinism comment...
Good find about the Ireland document by the way.
Anyhow, had enough to drink now, so up in the loft I've been, complete with vials of meths, white spirit, petrol and acetone. And camera.
Some of my lighting cables have been sunk in polystyrene for somewhere between 5 yrs (when we moved here) and 15 yrs (last "proper" electrical work/check)
15052008001.jpg

Meths and white spirit don't touch the stickiness. Acetone cleans off the polystyrene sticky but makes the pvc a bit sticky too. Petrol works a treat, and doesn't appear to affect the pvc at all.
15052008002.jpg

Now i'm no chemical expert, and I will eat my hat if the cables degrade tonight amid the remaining fumes and we evacuate a burning edifice, but I dont think so.
Interestingly (even more so) the second cable I looked at had dissolved the polystyrene into a film on the cable which I could peel off like a strip of dried PVA glue, without appearing to have affected the PVC at all.
15052008004.jpg

15052008007.jpg

And as far brittle? Feels and looks and flexes as if completely unaffected.
So there, science practical lesson over and all flammable solvents safely stored away (glug).
But to get back to the OP, I can't believe that a years worth of a few polystyrene beads is enough to warrant the cable unfit for purpose or a danger. Especially if you expect the electrician to replace the first leg of every circuit and more.
 
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wow, I'm amazed that so much damage can be caused in such a small amount of time, especially given the seemingly inert nature of the two substances involved.

Now that i have my lighting up in the loft all sorted, i think i'm going to have a good look around as i know there are some polystyrene boards stored up there.

I think i might install a new smoke alarm up there whilst i'm at it...

good thread...
 
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Ive pulled a fair number of tails from cavities with the polystyrene ball insulation but none of them have had the reaction that t&e does - why is that?
 
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So I've had my electrician in and he has put all new cable into the consumer unit, except the main feed and earth to the consumer unit which were fine. The new cables go in a short way, then they go to junction boxes. Remembering that above my consumer unit where all the cables came out was where the polystyrene attack was; there was a hot water pipe above it; and this is all in the hallway at the entrance / exit to the master bedroom. It could have been a disaster. So, I can sleep better at night now it is all new cables, with much more breathing space. Please see the photos. Well I didn't try any solvents to remove the stuff on the cables, I did find that the residue peeled off like old glue. I also found that the cables that had been attacked were a little less flexible.

Thank you to all for contributing to this thread.
 
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Dalibu,
Not sure if you're aware, but placing junction boxes in inaccessible places isn't considered good practice, as they're more likely to develop faults (loosening connections for example) than an unbroken length of cable. Or did he crimp and heatshrink the connections?
 
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Did you see my photos? The junction boxes are going to be beneath the floorboards. There are junction boxes all over my house, so I don't see how a few more is going to change anything.
 
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Yes I looked at the photos :eek: .
The thing is it's a known fact that junction boxes and other screwed connections can come loose in time. Stamping, slamming doors, temperature change...
If you get a fault on your circuit, it's difficult to know where to look.
JB's are fine in the attic, or any other location, as long as they can be seen and inspected.


While you've got the floors up it would be best, where possible, to replace any sections of cable with junction boxes on them with whole unbroken lengths. Although some of them are clearly not just connecting two cables together.
Or get a crimping kit and start crimping.

You don't want to hear this I know, but you know it makes sense.
 

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