4–4 EPM 9450/9650 ADVANCED POWER QUALITY METERING SYSTEM – INSTRUCTION MANUAL
ISOLATING A CT CONNECTION REVERSAL CHAPTER 4: ELECTRICAL INSTALLATION
DO NOT leave the secondary of the CT open when primary current is flowing. This may
cause high voltage, which will overheat the CT. If the CT is not connected, provide a
shorting block on the secondary of the CT.
It is important to maintain the polarity of the CT circuit when connecting to the EPM 9450/
9650 meter. If the polarity is reversed, the meter will not provide accurate readings. CT
polarities are dependent upon correct connection of CT leads and the direction CTs are
facing when clamped around the conductors. Although shorting blocks are not required
for proper meter operation, GE recommends using shorting blocks to allow removal of the
EPM 9450/9650 meter from an energized circuit, if necessary.
4.3 Isolating a CT Connection Reversal
For a Wye System, you may either:
• Check the current phase angle reading on the meter's external display (see
Chapter 6). If it is negative, reverse the CTs.
• Go to the Phasors screen of the GE Communicator software (see the GE
Communicator Instruction Manual for instructions). Note the phase relationship
between the current and voltage: they should be in phase with each other.
For a Delta System:
• Go to the Phasors screen of the GE Communicator software program (see the GE
Communicator Instruction Manual for instructions). The current should be 30
degrees off the phase-to-phase voltage.
CT size (VA) Maximum Distance from
CT to EPM Meter (Ft)
2.5 10
515
7.5 30
10 40
15 60
30 120
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