It may be possible that the load is causing a disturbance on the current harmonics.

If the load measured by this meter has a high 3rd and 9th harmonics, the "neutral harmonics", they are not cancelled among the phases and just drained to the neutral line. This explains the image where this harmonics represents about 20% to 30% of the fundamental current on the lines, but they are more than double the fundamental on the neutral.

The typical loads that causes this disturbance are switched power supply (computer/servers) connected on Line to Neutral plugs.

Released for: Schneider Electric Ireland