19
c. Loop impedance at 3-phase equipment
Use the same procedure as (b) ensuring only
1-phase is
connected at a time
i.e. FIRST test-red prod to phase 1,
black prod to neutral, green crocodile clip to earth;
SECOND test-red prod to phase 2, black prod to neutral,
green crocodile clip to earth etc.
d. The ACC016E can also be used for testing at light fittings.
Testing as described in (a), (b), (c) and (d) will measure the
Phase-Earth loop impedance. If you wish to measure the
Phase-Neutral loop impedance in items (b), (c), (d), then same
procedure should be followed except the earth clip should be
connected to the neutral of the system i.e. the same point as
the black neutral probe.
If the system has no neutral then you must connect the black
neutral probe to the earth i.e. same point as the green earth
clip. This will only work if there is no RCD in this type of
system.
4.3 Measurement of PSC (Prospective Short Circuit
Current)
Warning: Although it is fully protected (no bangs), never
connect phase to phase (400VAC) to this instrument.
This is normally measured at the distribution board between the
phase and neutral.
Connect the ACC016E distribution board lead to the IEC socket
on the instrument
Connect the red phase probe of the ACC016E to the phase of
the system, the
black probe to the neutral of the system
and
