37
UMG 509-PRO
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7.8.2
Example: Insulation of the residual
current transformers
A residual current transformer is used to mea-
sure on insulated mains wiring in a 300 V CAT III
network.
The insulation of the mains cables and the insula-
tion of the residual current transformer must meet
the basic insulation requirements for 300 V CAT III.
This corresponds to a test voltage of 1500 V AC (1
min. duration) for the insulated network wiring and
a test voltage of 1500 V AC (1 min. duration) for
the residual current transformer.
ATTENTION
Transmission error and material damage due to
electrical malfunction.
With a cable length of more than 30 m, there is an
increased probability of transmission errors and
damage to the device due to atmospheric dis-
charge!
Use a shielded cable for the connection to the
residual current transformer inputs.
Fig. Example of UMG with residual current monitoring via measurement inputs I5/I6.
Residual current transformer
Residual
current
transformers
WARNING
Risk of injury due to electrical voltage!
The Profibus, RS-485, temperature measurement
input and residual current measurement input are
not galvanically isolated from each other.
Consequently, it is essential to note that dan-
gerous voltages at these inputs can have an
effect on the other respective connections.
L1 L2 L3 N
I1
I2
I3
L1
L2
L3
PEN
N
PE
UMG 509-PRO
M
3~
I5
I6
I4
