Old domestic internal switchboard linings - Asbestos?

[WireWizard]

Hey guys - just wondering what you all do with the plasterboard style mineral linings that are inside the old ACM hinged switchboards? Many of them appear to be straight plasterboard, but many look much tougher and therefore seem more likely (to me) to contain asbestos. Also the original sealant they used I would assume to be asbestos too - the stuff that goes hard like plaster and is around all the original cabling entry. Do you guys use shaving foam on everything when drilling holes/removing linings to do an upgrade? Is there another less messy way to go? Or is treating this fireproof lining as asbestos just over kill. TIA

[AlecK]

If the lining of a grey cement-board type, then it's likely to be ACM - "Polite" or equivalent.
There's also a much softer type that's common, with grey fibrous structure; easily penetrated by screwdrivers etc
That's "millboard" or equivalent, and 100 % asbestos.
You'll find similar stuff used to insulate some older HWCs

But if what you have is very white, with brown fibres mixed in; then probably just simple "fibrous plaster", and plaster (with or without fibre) the only stuff I've seen used for original cable entries. Check what the walls / ceilings are lined with, and of it's the same stuff then no asbestos concerns.

[WireWizard]

Thanks AlecK, your response has been detailed and very useful as always, much appreciated