On Aug 11, 12:13 am, (Andrew Gabriel)
wrote:

Functional switching should be handled differently from
isolation for maintenance. They might both need to be key
operated, but that doesn't mean they need to use the same
keys or switches.

I have now discovered that there is yet another isolation switch
elsewhere in a locked metal cabinet. The electrician had switched that
off as well as putting a "Danger Leave Off" sign on the other switch.
When he switched the second isolation switch on again he noticed that
it was live. So no real danger then. A new padlock on the first switch
for just him will solve the problem I think.
Moral of the story - don't assume that people will read warning signs.