On Sun, 13 Mar 2016 17:58:55 -0000, "Mr Macaw" wrote:

In the US we only protect single branch circuits or individual loads
with a GFCI but that is at 5ma.
When we see 30ma protection, it is called "ground fault protection for
equipment" because we think 30ma is too high to protect people.
One thing you must keep in mind is 5ma might not kill you but it can
still cause you to fall off the ladder.

Then use battery or petrol driven tools up a ladder.

This usually involves someone working on a ceiling light or other
electrical equipment.

Here's a novel idea, turn the light off first.

The problem is when there is more than one circuit in the box or when
people assume all white wires (neutral here) will be grounded. If you
open up that wire nut only one of those wires with be ground, the
others may be at full line voltage through the connected load.