What is the powder inside power leads ?

Hi Guys,

I hope this isn't a stupid question. I'm curious; what exactly is the powder between the outer sheath and the inner conductors in a mains power lead? I'm talking about the stuff that gets everywhere when you strip a lead to replace a power plug or socket. Its inside every Australian lead I've ever worked on - I guess US ones are the same.

Thanks for your help.


Reply to
Darren J. Paul
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My guess is it's powdered talc.


Reply to
Grant Erwin

White powder! White powder!! Call Homeland Security *Now*!! :)

Reply to
David R Brooks

The cable in question equivalent in Canada and USA is Pyrotenic cable, the insulation is clay if my memory serves me well. Pretty much a thing of the past now but it is out there.


Reply to
Pete T

as a lubricant to help the cables flex?

Reply to

No Pete the o/p is talking flexible cable to an appliance I think. Pyro (M.I.C. or Mineral Insulated Cable) is for fixed wiring and usually specified for areas of fire hazard or services that must survive a fire for a period like emergancy lighting.


Reply to
Andrew Mawson

Yes and No. . Its to stop the wire(s) sticking to the sheath, makes life easier when stripping them.....also, provides a little bit of "slip" between the wire and the sheath, useful for cables that get flexed a lot....no doubt there are now more "modern" plastics used for this that dont need the talc...

Andrew VK3BFA.

Reply to
Andrew VK3BFA

This is my understanding too.

Best wishes,


Reply to
Christopher Tidy

My guess its talc. But why? my further guis that most cables today are made with plastic or pvc. this is extruded hot around the inner insulated leads. the talc is to prevent the outer from bonding to the inner pvc so the electrician can strip them easily.

Reply to
ted frater

Yes, to stop the insulation on the individual wires from binding on the outer sheath. Without the talc, you wouldn't be able to coil the cable.

Reply to

Interesting. Talc makes sense; I hadn't thought about the need for the conductors to slide inside the sheath when the lead is flexed / coiled.

This is in a brand new cable, BTW.

Thanks guys.


Reply to

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