METREL MI 3399, Instruction Manual With Exercises

Page: 105 / 272

Electrical Installation Safety Trainer AD 1 - MI 3399
105
Before conducting any measurements, the measuring instrument has to be
calibrated. First connect the PE a neutral cables together to create a PEN cable,
then connect the tips of the PEN and phase cable and run the calibration (right
orange square in picture above). This way the resistance of the cables will be
removed when measuring conductor continuity. Once the instrument is calibrated
a “CAL” icon appears on the screen (middle green square in picture above).
3 During this type of measurement only the cables may be used. Connect the PE a
neutral cables together to create a PEN cable and place it on a reference point
somewhere in the building (e.g. the MPE). Check all PE wires in all sockets
available with the phase cable.
4 Press the START key.
Expected results
In a normal situation, the measured continuity resistance must be below 2
Ω. This limit
always applies when continuity is measured in a RCD protected system. If no RCD is
present the allowed continuity resistance is usually much lower since it depends on the
fuse used in the measured circuit (e.g. in a circuit protected by a C20A fuse the
maximum allowed continuity resistance would be 0,25
Ω).