"Andrew Gabriel" wrote in message
...
In article ,
"ARWadsworth" writes:

It could be labelled ELCB if it is one of the older types. Also as you
say,
the old units frequently are connected to earth whereas an RCD is not.

Some RCD's have earth connections too. A unique feature of a Voltage
Operated ELCB is that it has two separate earth connections -- one
to the house wiring, and the other to the earth rod. It operates by
measuring the voltage between these two connections.

--
Andrew Gabriel

I was thinking of it being an RCD (ELCB) with an active earth connection, or
so I would have thought due to the age of the installation as the OP
mentions.