I was curious, so I just tested some of my festool hoses with an insulation tester (a megger) that builds up to 1000V max.
The megger was connected with a crocodile clamp to the plastic bit that goes into the vacuum and I pushed a probe pin onto the inside of the hose at the inlet (past the rubber sleeve that connects to your tool)
my newest green and black 36mm AS flexible hose (the one with the braided outside) starts conducting at about 140V.
my older green and black 27mm AS hose (with the ribbed outside) started conducting at about 180V.
the grey hoses from my CS50 don't seem to conduct at all (the megger build up to 1005V)
I also saw that the part of the vacuum where you plug your hose in is connected to the ground wire of the vacuum's power plug.
What I found interesting is that the rubber end that connects to your tool is non conductive, so the hose is only anti-static past that connection.
So I guess the idea is that static that builds up in the hose by particles that whizz trough and rub against the plastic of the hose gets diverted to the ground (earth) through the vacuum instead of through a person touching the hose.
It might also help to prevent particles sticking to the hose as static can do that (the famous "rub a plastic ruler in your hair and you can attract little pieces of paper with it" test).
So quite clever engineering, these AS hoses (in my opinion).
Could using a cyclone that is not made of conductive plastic damage the electronics of someone's expensive Festool vacuum? I have no idea, but if I designed such a cyclone (or is it a box that holds another manufacturers cyclone that you designed?), I sure would want to know before I start selling a lot of them (and maybe get a good lawyer
![Big Grin [big grin]](https://www.festoolownersgroup.com/Smileys/default/biggrin.gif)
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No offence intended, just trying to be helpful.
Best of luck,
wpz