16
DANGER!
To avoid accidents, the following must be observed::
The safety instructions in
Section 5, Installation, page 12.
When work is carried out on the instrument terminals and connecting cables, there is a risk of live
components being touched inadvertently. The working voltage may present a hazard to health or
may even be life-threatening.
Observing the above safety precautions can significantly reduce the risk to life and limb.
The preferred arrangement is to connect all three phases L1, L2 and L3, plus the neutral conductor N and the
protective earth PE. Instead of the PE conductor, another voltage source can also be connected, provided that its
parameters are within the range specified in
Section 2 Technical data, page 7
.
This 3-phase connection is to the terminals
L1
,
L2
,
L3
,
N
and
Lx
as
shown in the diagram
Figure 5, page 14
, where in addition the variables in
the N and PE conductors are also measured.
Figure 6, page 14,
shows the alternative single-phase connection.
It is advisable to connect the N conductor as well as the three phases.
This enables the high measurement accuracy of the EM-PQ 2300 to be achieved when measuring phase
–neutral
voltages and the parameters derived from these. If no neutral conductor is present, the
N
terminal can be left
unconnected. However, in this situation a virtual star point arises in the instrument, which implies that the values
of the phase
–neutral voltages are nearer to each other than necessarily the case. The parameters derived from
these values will be similarly misleading.
Leaving N unconnected is only advisable when the phases are symmetrically loaded, since as a rule the phase
–
neutral voltages here are near to each other in value.
NOTE!
The voltage measurement inputs not in use must be commoned with the terminal
N
. This is
necessary, for example, with single-or two-phase connections.
If this is not done, phantom measurement readings may be displayed for the inputs that are not in
use.
NOTE!
When the Lx terminal is connected to the PE conductor to measure the voltage in it, as shown in
Figures 5 and 6, a green/yellow cable must only be used between the connection point in the
installation and the 2 A fuse, never between the fuse and the terminal Lx on the EM-PQ 2300. The
cable between the fuse and the terminal Lx must have a completely different colour!
If this is not ensured, it is possible that the terminal Lx on the EM-PQ 2300 may then be mistaken
for a normal PE connection, and an additional earth conductor could be commoned there as well.
This would be incorrect, since it is not permitted to route PE connections through disconnecting
devices such as fuses.
5.1.2.2 Current measurements
The EM-PQ 2300 is designed for connection to x/1 A and x/5 A current transformers. Only AC currents can be
measured, not DC currents.
DANGER!
To avoid accidents, the following must be observed:
The safety instructions in
Section 5, Installation, page 12
The current measurement inputs must be connected as specified.
When work is carried out on the instrument terminals and connecting cables, there is a risk of live
components being touched inadvertently. The working voltage may present a hazard to health or
may even be life-threatening.
Observing the above safety precautions can significantly reduce the risk to life and limb and
potential damage to equipment.
