PUB 51079
D64RP14 SERIES A2 DIGITAL GROUND FAULT RELAY
Revision 1
May, 2005
Page 9
The D64RP14 will work with Eaton’s Cutler-Hammer C311CT current transformers having a turns ratio
of 500:1. These are epoxy molded to give exceptional mechanical properties and have high-grade
silicon iron cores for excellent coupling characteristics.
Refer to section 4 to select the catalog number of the C311CT current transformer with the opening
required for the application.
Phase conductors must be insulated for the system voltage when it is higher than 660 Volts.
Refer to Figure 2. 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.
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 two secondary terminals of the external CT are to be connected to terminals T1 and T2 of the
D64RP14.
3.4
CONNECTIONS
All connections to the D64RP14 are by means of two screw clamp terminals per pole (Double Row T
Connector) rated 10 Amps, 300 Volts. Each screw clamp terminal will accept #26-12 AWG solid or
stranded conductors.
The terminals are pull apart.
For remote metering connect a meter having a 0-10 volt movement with a 0-100% scale to terminals
M+ and M-. Observe polarity when making the connections.
Note
: Terminals M+ and M- are NOT isolated from the control voltage; terminal M- is internally
connected to terminal N-.
If an external CT is being used, connect the two secondary terminals of the CT to terminals T1 and T2
of the relay using 14 AWG (minimum). Twist the leads to optimise electromagnetic immunity.
Note
: The CT’s input terminals T1 and T2 are NOT isolated from the control voltage. If an external
CT is used it is grounded internally via the power supply input and
must not
be grounded
again externally (ground loops).
For remote Test and Reset connect a N.O. momentary contact TEST/RESET button to terminals R1
and R2.
Note
: Terminals R1 and R2 are NOT isolated from the control voltage; terminal R2 is internally
connected to terminal N-.
Connect ac or dc control power to terminals N- and L+. Observe polarity.
In order to meet the Electromagnetic Compatibility (EMC) requirements a chassis bond is required
between terminal N- and the nearest ground point. This distance should be kept to an absolute
minimum. If the D64RP14 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.
Refer to Figure 1, Figure 2, 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.
