Three phase Voltage measurement using zmpt101b

Other Hardware General Electronics
6

You have got that the wrong way round.

https://en.wikipedia.org/wiki/Three-phase_electric_power

In a symmetrical three-phase four-wire wye system, the three phase conductors have the same voltage to the system neutral. The voltage between line conductors is √3 times the phase conductor to neutral voltage:
{isplaystyle V_{ext{LL}}={qrt {3}}V_{ext{LN}}.}