bulbs connected to a three phase system - what is the current in neutral conductor?
If you put 2 bulbs in series, the current is more than 50% since the R vs temp changes over a 1:10 range from cold to hot due to the PTC characteristic of tungsten.

What ever the difference in current between L3 and the average of L1 &amp; L2 is the net neutral current as these all have pf=1 phasor currents.