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CLASS 320 METER
6.4.1 Current Sensor Wiring
Once the current sensors are installed onto their appropriate phase conductors, you
can begin terminating the current sensors onto the Class 320 main board. The current
sensors can be extended up to 500 feet for remote monitoring applications. To extend
the length of the wires, use #22 AWG twisted-pair wire with one white and one black
wire.
The easiest way to connect the current sensors is to use the meter's built-in current
sensor diagnostics. To do this, there must be at least 1% of the meter's current rating
(amps) flowing in each of the conductors being monitored. The Class 320 meter's
diagnostic program (on the 4-line display) will provide data to ensure that the current
sensor installation is done properly.
The current sensor connection points are located at the bottom right of the main power
board. These are TB2, TB3, and TB4. Each sensor connects to two terminals one
labeled "Black" and the other "White." Current sensors should be connected to the
meter one at a time and verified using the current sensor diagnostic program.
Connect one of the current sensors to the TB2 terminals (Phase A). Tighten the
terminal to 4.5 in-lb. Wait 5 seconds and look at the meter display.
If the meter displays an error message (see below), remove the wires from TB2 (Phase
A) and install them on TB3 (Phase B). if an error message occurs with the sensor
attached toTB3, try again on TB4 (Phase C). The wiring will be correct when the error
indication message is gone.
NOTE: If the power factor being monitored is <65%, the error message may be acti-
vated until improved. This is normal and indicates poor power factor.
The "CT Error: * "message will disappear when the current sensor is connected to the
correct terminals (phase).
Error Messages: CT ERROR: A
NOTE: The Single Phase option will only display errors for A and B.
Refer to the section on Current Sensor Diagnostics for assistance in troubleshooting
these errors.
6.4.2 Main Power
After the meter circuit wiring has been examined for correctness, power may be
applied to the circuit board. There are three LEDs located in the upper right corner of
the Meter Board labeled BEAT, STATUS and LOAD. The BEAT and STATUS LEDs will
blink once per second when the meter is operating normally, twice per second if there
is a problem.If the monitored circuit is under load the LOAD LED will actively blink. A
heavy load will cause the LED to blink faster than a light load. Very light loads will
result in an extended blink time.
62-0397-02
CT ERROR: A B
CT ERROR: A C
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