CH1 applies to all voltage channels
(unless in single phase 2 or 3 wiring)
CH2 applies to all current channels
(unless in single phase 2 or 3 wiring)
CH3 and 4 apply to phase 2 voltage and
current when in single phase 2 wiring
CH5 and 6 apply to phase 3 voltage and
current when in single phase 3 wiring