PUB 50413
D64RPBH13 SERIES B1 GROUND FAULT RELAY
Revision 2
September, 2009
Page 11
3.2
EXTERNAL C311CT CURRENT TRANSFORMER
The D64RPBH13 is designed to operate with either, a special Eaton’s Cutler-Hammer C311CT zero
sequence current transformer with a turns ratio of 10000:1 or, the standard family of C311CT zero
sequence current transformers with a turns ratio of 500:1. Each C311CT is epoxy molded for
exceptional mechanical properties and has a high-grade silicon iron core for excellent coupling
characteristics. C311CTs have built-in back-to-back zeners across the output terminals to provide
maximum safety in the event of an open CT secondary circuit.
Refer to section 4 to select the catalog number of the C311CT current transformer with the opening
required for the application. . Each C311CT is epoxy molded for exceptional mechanical properties and
has a high-grade silicon iron core for excellent coupling characteristics. C311CTs have built-in back-to-
back zeners across the output terminals to provide maximum safety in the event of an open CT
secondary circuit.
Phase conductors must be insulated for the system voltage when it is higher than 660 Volts.
Refer to Figure 1. Pass the phase conductors through the CT window. If the neutral conductor is being
connected downstream, it is to be passed through the window. Do not pass ground conductors through
the CT window. In applications that require shielded wires to pass through the CT window, return the
shields through the CT window before connecting them to ground.
Position power cables in the center of the current transformer opening. Keep cables and buswork clear
of the split on split core current transformers.
3.3
CONNECTIONS
All connections to the D64RPBH13 are by means of screw clamp terminals rated 10 Amps, 300 Volts.
Terminals will accept #26-12 AWG solid or stranded conductors.
The terminals are pull apart. They have two 12 AWG screw clamps per pole with 90
°
and 180
°
orientation. A screw mounted locking block is located at each end of the terminal block for maximum
security.
Since the relay housing is non metallic, no chassis bond is required.
For good EMC behaviour the following wiring practices are recommended:
-
Connect the FB (“Frame Bond”) terminal to the structure ground as close as practically
possible to the component being grounded using the shortest wire.
-
The D64RPBH13 has an isolated power supply. Therefore the N- terminal should be
connected to the structure ground at the same point as the neutral of the control
transformer. See figure 1.
-
Avoid looping or coiling any/all wires connected to the component.
-
Dress all conductors as close as practically possible to the back panel or grounded
frame.
-
Use shielded twisted leads on interconnection between CT and Relay.
-
The shield should extend the full length of the twisted interconnection leads.
-
Connect shield to structure ground as close as practically possible to the Relay.
-
When stripping conductor insulation care should be taken to avoid breaking any
conductor strands.
Connect 110-240 Volt ac/dc control voltage to terminals L+ & N-.
Refer to Figure 1 and Table 4. Decide on the connection of field devices to output circuit breaker
contact terminals by comparing the desired control of the field devices under various operating
conditions.
Figure 1 shows a typical connection of a 120 Volt ac circuit breaker shunt trip coil (ST) to the closed
contact of the output circuit breaker. Comparing the output circuit breaker contact states, it can be seen
that this could be used with the NON-FAILSAFE operating mode. The N.C. contact, terminals 11 & 12,
(open when the circuit breaker toggle is placed in the NORMAL position) would be used for the shunt
trip coil circuit.
