For what it’s worth … the cheap and nasty cable is branded KEMA-KEUR and proudly carries its details
… too much information to be worth quoting here; except to mention that the conductors are each.0.75mm^2, which is rather hefty for 25W
**LINK** https://www.dekra.com.cn/en/cables-and-wiring/
The cable is dated 1997, and the product was supplied by ‘Comet’
[ I picked it up, apparently unused, at a Charity Shop ]
The box states that it uses “PTC technology” and works on 100V to 250V”
… this may, or may not, also imply that the soleplate is adequately insulated from the electrics
MichaelG.
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Here’s what little I currently know about PTC heating: **LINK**
https://www.pelonistechnologies.com/blog/three-benefits-of-ptc-heating-technology
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Edit: __ Thanks for the recent posts 
Edited By Michael Gilligan on 06/04/2021 20:20:17