One thing that has to be remembered about a plain vanilla Residual Current Device.
That's all it does, is sense an imbalance between Phase and Neutral in a circuit.
A RCBO, has two functions, it senses like the RCD does, but it has the features of a Circuit Breaker built in to it.
The term RCCB and ELCB mean the same thing.
However, Voltage Operated ELCB's were a different kettle of fish, they were only used where the basics of earthing could not be provided and used to trip if the voltage got above 22VAC, with reference to earth (cold water pipe).
They were used here in places at (usually) the ends of long spur lines, where the ground was so rocky that if you went to sink a rod, the thing would either bend and come up a foot or so away from where you were driving it or on the first hit, would disappear into oblivion below.
They used to be really bad things, trip at night when the soil temperature dropped below a certain value.
Considering that they were sealed by the local Power Company here, the Home-owner was not allowed to reset them.

{Message edited to remove a few typo's} [Linked Image]


[This message has been edited by Trumpy (edited 12-01-2006).]