In article .com,
wrote:
Thanks. I get it now. The CU has two terminal strips, earth and
neutral. The live and neutral come in and connect to the "top" of the
RCD switch. The earth goes straight to the earth terminal. The output
of the RCD switch has the live going to the two mcbs via a amll bus bar
link, the neutral to the neutral terminal strip. When the RCD is off
there is no supply to the live bus bar or neutral terminal strip,
cutting out the lives and neutrals to all circuits. This makes sense.
The mcbs have the live from the output of the mcb and take take the
neutral from the common neutral terminal trip.

Just the same as any CU. The master switch - or RCD - is double pole. MCBs
- or even fuses - are only on the line. Split load CUs are more confusing
as you need two neutral busses - one for the RCD protected side and one
for the non RCD one.

--
*TEAMWORK...means never having to take all the blame yourself *

Dave Plowman London SW
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