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PUB 50412
D64RPB100 SERIES B1 DIGITAL GROUND FAULT RELAY
Revision 3
April, 2008
Page 10
Verify that the polarity of the conductors is correct when they pass through the CT. Verify that
ground paths do not exist that would bypass the CT.
Position power cables in the center of the current transformer opening. Keep cables and buswork
clear of the split on split core current transformers.
The 5 Amp secondary lead from the interposing CT is to pass through the window of the built-in
CT of the D64RPB100.
3.5
CONNECTIONS
All connections to the D64RPB100 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. A screw mounted locking block is located at the left end of the 7 point
terminal block for maximum security.
Connect ac or dc control power to terminals 1 and 2.
In order to meet the Electromagnetic Compatibility (EMC) requirements a chassis bond is required
between terminal 3 and the nearest ground point. This distance should be kept to an absolute
minimum. If the D64RPB100 is mounted on 35 mm DIN rail a DIN rail mounted ground terminal
block can be installed beside the relay to act as the chassis ground point. Use a minimum 14
AWG stranded conductor.
Refer to Figures 1, 2, and 3 and Table 2. Decide on the connection of field devices to control
voltage and output relay contact terminals by comparing the desired control of the field devices
under various operating conditions.
Figure 1
shows a typical connection of an ac motor starter coil (1M) to the N.C. contacts of the
output relay (terminals 11 and 12). Comparing the output relay contact states, it can be seen that
this could be used with the NON-FAILSAFE operating mode. The N.C. contact, terminals 11 & 12,
would be used for the starter coil circuit. The N.O. contact, terminals13 and 14, control the remote
red TRIP light. Note the remote TEST/RESET pushbutton.
Figure 2
shows the D64RPB100 using an external current transformer (C311CT 500:1 ratio) and
a typical connection of a circuit breaker with a shunt trip coil (ST). With the 500:1 ratio CT, the trip
level range of the D64RPB100 remains at 30 mA – 9 Amps. (Pulsed Trip Auto Reset operating
mode has been selected on DIPswitches 9 and 10). Comparing the operating mode and the relay
contact states in Table 2, it can be seen that the N.O. contact, terminals 13 and 14, would be used
for the shunt trip coil. The D64RPB100 will reset automatically as soon as the ground fault current
is interrupted by the tripping action of the circuit breaker.
Connect the secondary leads of the external C311CT current transformer to terminals T1 & T2 of
the D64RPB100, using 14 AWG (minimum). Twist the leads to optimize electromagnetic
immunity.
Please note that terminal T2/R2 is internally connected to terminal 3 of the D64RPB100. Since
terminal 3 must be grounded, it means that the C311CT secondary circuit will be grounded
automatically. If separate grounding is required by electrical regulations, the C311CT terminal
connected to T2 should be connected to the same grounding point as terminal 3 of the
D64RPB100. This will avoid ground loops and nuisance tripping.
Figure 3
shows the D64RPB100 using an interposing current transformer (500:5 ratio) and a
typical connection of a circuit breaker with a shunt trip coil (ST). With the 500:5 ratio CT, the trip
level range of the D64RPB100 is now 3 – 900 Amps. (Pulsed Trip Auto Reset operating mode has
been selected on DIPswitches 9 and 10). Comparing the operating mode and the relay contact
states in Table 2, it can be seen that the N.O. contact, terminals 13 and 14, would be used for the
shunt trip coil. The D64RPB100 will reset automatically as soon as the ground fault current is
interrupted by the tripping action of the circuit breaker.
The 5 Amp secondary lead from the interposing CT is to pass through the window of the built-in
CT of the D64RPB100. Twist the leads to optimize electromagnetic immunity.