Silicone cable safety

[Refugee]

I was about to do a quick repair using a hot melt glue gun and suddenly discovered that it had what looked like a badly wired plug with the cable pulled part of the way out of the grip saddle.
When I looked more closely the silicone rubber cable had gone all sticky and soft close to the plug while remaining normal along its length.
Once I had removed the plug it was obvious to me that the rubber had rotted most where it contacted the nylon grip saddle. The part that was in contact with the plug body was far less degraded.
These two plastic materials obviously react so If you have mains powered kit with silicone mains cables make sure there is a sleeve fitted under the cord grip saddle.
My estimation based on the age of the glue gun sets the rate of migration of the decay from the nylon into the flex insulation to be about 1mm per year.
I would advise you check your silicone mains cables and fuses in order to save yourself a rood awakening. It is class II so the RCCD will not stop it going BANG if you fail to spot this problem.
I did fit a 3 amp fuse before using it again.

[ppppenguin]

I'm surprised by this. Always though that silicone rubber was pretty much immune to almost everything. Was it definitely silicone and not butyl rubber?

[Crackle]

It looks like lawnmower cable.

Mike

[Refugee]

It is the original cable on a hot melt gun.
PVC reacts in the same way if it is left in contact with some types of plastic foam.
It looks to me like the same problem however this time it is silicone and nylon.
It looks a bit like the stickyness we sometimes see on handle bar grips and such like but triggered by nylon.
I once had a computer mouse that went all sticky with little or no excuse.

[Terry]

It looks to me as if the sheath under the clamp is in perfect condition but it is the section adjacent to it that has decomposed.

What did it look like after you removed the clamp?

I'm not convinced, on the basis of that picture, that your conclusion is correct. However, I can't think of another logical reason for it!

[Refugee]

The rubber was still flexible but could easily tear for about an inch away from the saddle in both directions.
Under the saddle it had turned to orange putty. I just pulled the two conductors until the sheath offered a normal amount of resistance and fitted the plug with a sleeve over it to stop the chemical migration that lead to the problem. It was about two inches.
I suspect the catalyst/hardener that is added to the liquid resin to harden it into plastic at the time of manufacture.

[boater sam]

Discovered that Scotchguard fabric protection spray will destroy silicone rubber, more useless info to clutter my little grey cells.