Answer Posted / s. malhotra

Restricted EF relay is meant for sensing earth fault/
leakage current in a "restricted zone", a zone bound by the
2 sets of Current transformers - one set at the beginning of
the zone and one at its end.

There is NO particular zone restriction for the normal Earth
leakage relay which will sense an earth fault or earth
leakage downstream of it. Though you may call the entire
downstream as a zone, in comparison to the REF it is left
unqualified

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