Eaton EDR-5000 Nstallation, Operation And Maintenance Manual page 41

Common CT Wiring Configurations
Check the installation direction.
Sensitive Ground Current Measurement
The proper use of sensitive current measuring inputs is the measurement of small currents like they could occur in
isolated and high resistance grounded networks.
Due to the sensitiveness of these measuring inputs don´t use them for the measurement of ground short circuit currents
like they occur in solidly earthed networks.
If a sensitive measuring input should be used for the measurement of ground short circuit currents, it has to be ensured,
that the measuring currents are transformed by a matching transformer according to the technical data of the protective
device.
CT Connection Options
The current transformers may be connected in several ways, and the specified configuration affects the way system
measurements are made and results computed. The computation of the residual current IR, is dependent on the
system configuration setting for the CT connection. The configurations resulting from the setting options are shown as
well as the calculated IR residual current.
It is imperative that the secondary sides of measuring transformers be
grounded.
The current measuring inputs may exclusively be connected to current
measuring transformers (with galvanic separation).
CT secondary circuits must always to be low-burdened or short-circuited
during operation.
For current and voltage sensing function external wired and appropriate
current and voltage transformer shall be used, based on the required input
measurement ratings. Those devices provide the necessary insulation
functionality.
All current measuring inputs can be provided with 1 A or 5 A nominal.
Make sure that the wiring is correct.
EDR-5000
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IM02602007E
41