The 3+N-pole format provides overcurrent protection on all three phases plus a switched neutral, which is required in some regional wiring regulations (e.g., UK and parts of Europe) where the neutral is not fused but must be disconnected with the phases.
Compliance documentation
RoHS compliant since June 1, 2013. REACH candidate list information is available from the manufacturer. Export control regulations are AL: N / ECCN: N, meaning no special export license is required for most destinations.