What wire strippers do i need for 3 core (1cm+) wire?

[CountryFan]

That's a damp proofing wire, and I know about those (be they snake oil or otherwise!). A "damp-proof installation cable" is presumably very different from that, but I have no idea what it is.

Apologies, I stand corrected.

 

[Diver Fred]

Me thinks you need to visit a specialist Electrical dealers such as CEF as listed in @opps response above and ask there. Yes it may cost a little more but I believe you will have a better chance of obtaining exactly what you require.

I suspect the DIY shop person you asked mistook your up to 1.5cm request for 1.5mm.

 

[mattylad]

I use one of the ones you rotate around the round cable daily.
Works very well although you do need to adjust the blade depth on a scrap piece to ensure you are not cutting into the inner cores as not all insulated round cables have the same thickness insulation.

 

[333rocky333]

What exactly is a "damp-proof installation cable" ?

Possibly Artic flex, the yellow and blue stuff used for festoon and stuff outdoors