Notice the "press monthly" marking on the test button of the unit pictured above. 99% of users in this country won't even notice that instruction, nevermind carry it out.
Interesting document on the development of ELCB/RCD use in S.A. This passage caught my eye:
A school of thought exists in South Africa that suggests that the provision of sensitive earth leakage protection could be dispensed with by changing the distribution system from the existing 400/231 three phase grounded neutral system, to a 110-0-110 Volt single phase, centre point earthed system similar to that used in the USA, but providing 220 Volts across the outer lines. The theory, is that with a maximum of 110 Volts to earth, no shock hazard would exist.
I've noticed that a large number of people on this side of the Atlantic seem to look upon 110V in this manner.
