Utility Relay Company AC-PRO-II, Instruction Manual

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AC-PRO-II
®
Instruction Manual www.utilityrelay.com
Page 11
+
Actuator Phase A Phase B Phase C Neutral
-
Current Inputs
Normal Power Flow
Phase A
Phase B
Phase C
Neutral
Breaker Harness Cable
Breaker Harness Plug
LOAD
Neutral CT Connector
WIRE CODE
R = Red
B = Black
W = White
Y = Yellow
L = Blue
N = Brown
G = Green
CL = CLEAR
BA = BARE
R B L W Y W N W G W
Phase CTs
3-Phase
Source
CT Configuration shown
is for "Ground Fault
Return" protection type.
(Neutral CT input is
used for Ground Fault
Protection)
AC-PRO-II
Ground Return CT is optional.
Only on 4-wire system with
Ground Fault protection.
Figure 5.4: AC-PRO-II Typical Ground Return Wiring Diagram
The breaker wiring harness connects the trip unit to the CTs
and actuator. The wiring harness plugs into the 10-pin
connector on the front of the trip unit and is retained with two
screws. The breaker wiring harness includes wires for the
Actuator, Phase A CT, Phase B CT, Phase C CT, and
optional Neutral CT. Two ejector levers are provided to help
in disconnecting the harness connector. The ejector levers
also lock the connector in place.
A neutral CT wiring harness is provided as part of the neutral
CT installation kit. The neutral CT kit is required for units
applied to 4-wire systems where Ground Fault protection is
desired or required. The ground fault function on a 3-wire
system does not require a neutral CT. Additionally, this
connection method allows Neutral Overload Protection to be
implemented.
The breaker wiring harness connection to the AC-PRO-II is
compatible with existing AC-PRO breaker wiring harness.
The AC-PRO-II is compatible with multiple types of existing
Ground Fault protection schemes.
Figure 5.3 shows a residual Ground Fault wiring diagram.
For this configuration, the AC-PRO-II calculates the residual
Ground Fault current. If the system is a 4-wire
(3-phase + neutral), the neutral CT must be provided if
Ground Fault protection is desired.
Figure 5.4 shows a ground return Ground Fault wiring
diagram. For this configuration, the AC-PRO-II directly
measures the Ground Return current on the neutral current
input. This configuration only applies to 4-wire systems
where Ground Fault protection is required. Neutral Overload
protection cannot be implemented if the Ground Fault type is
Ground Return.
See Section 11.13 for Ground Fault settings.
Contact Utility Relay Company if your Ground Fault
Protection scheme is different than the typical schemes
shown above.
**** NOTE ****
For Ground Fault protection at Mains & Ties of 4-wire
double-ended substations, see Technical Bulletin #1 at the
link below:
http://www.utilityrelay.com/Side_Bar/Technical_Bulletins.html
All AC-PRO-II trip units are equipped with the capability of
connecting to an AC-PRO-II QUICK-TRIP Switch, which
provides arc flash hazard reduction. Refer to Section 7.0 for
QUICK-TRIP system information.
The auxiliary terminal block is available for the alarm relay
output, Ground Fault defeat Input, and breaker position
input. See the terminal labels in Figure 5.3.
Wiring for the auxiliary terminal block is not furnished in
AC-PRO-II retrofit kits.
The auxiliary terminal block features set-screw connections
and accepts #14AWG - #30 AWG conductors.
The AC-PRO-II is equipped with an internal configurable
alarm relay that has (1) Form C output contact for external
wiring. The output contacts are rated 5A @ 120VAC or 5A
@ 24VDC.
The configuration of this relay is included in the settings
menu. All related alarms and errors result in a specific
message on the display screen. The alarm relay can be
configured to operate for any combination of the conditions
5.1 Breaker Wiring Harness
5.1.1 Ground Fault Wiring Configurations
5.2 QUICK-TRIP
®
Connector
5.3 Auxiliary Connections
5.3.1 Configurable Alarm Relay