Either solution is correct. AS/NZS 3000 Clause 2.9.4 requires that the neutral bar is provided with a separate terminal for incoming and outgoing neutral conductor associated with active conductors originating or terminating at the switchboard.
All final subcircuits fed from an RCD can have all the neutrals terminated into the outgoing neutral terminal of the RCD; or have separate bars to terminate the neutrals of each RCD final subcircuit, with a single neutral connected to the outgoing neutral terminal on the RCD. In both cases, the neutral feed from the main neutral bar must be connected to the incoming neutral terminal on the RCD.
Because the main neutral bar is numbered, the way to identify the circuits is to match up the neutrals (and earths) of the subcircuits on their respective bars, that is, range terminal 2, hot water terminal 3, RCD1 terminal 4, and so on. Likewise, where an MCB (4) feeds three final subcircuits, then both the neutrals and earths must be twisted together and screwed into terminal 4 of their respective bars.
Bars (three-way) that can be screwed into the outgoing neutral terminal on the RCD to terminate the multiple neutral conductors are available from electrical wholesalers.
Terminating the multiple neutrals into the RCD appears to contradict clause 2.9.4 of AS/NZS 3000, but it is an acceptable alternative.
