15
VOLTAGE MEASUREMENT
When connected to a system using the three wire lead set or mains plug
the instrument indicates the greatest voltage on the system.
Phase to earth voltage measurement
Note: measured voltage must not exceed 300 V phase to earth.
To measure the voltage of the electrical supply:
1. Set the instrument to the [V] range.
2. Connect the GREEN or (L0) lead to the protective earth (PE) and the
RED or (L1) lead to the phase to be measured.
3. The instrument will display the phase to earth voltage.
Phase to Phase voltage measurement (LT320 and LT330)
NOTE:
measured voltage must not exceed 300 V phase to earth.
To measure the voltage of the electrical supply:
1. Set the instrument to the [V] range.
2. Connect the GREEN or (L0/L2) lead to the first phase, and the RED or
(L1) lead to the second phase.
3. The instrument will display the Phase to Phase voltage.
Prior to measuring Zref, all main equipotential bonding must be in place.
Note:
Measurements made on live installations by this method may be
lower than the Ze + (R1+R2) from those obtained by continuity testing
methods, due the existence of parallel earth return paths from extraneous
conductive parts.
