GE EPM 5200, EPM 5300, EPM 5350 instruction manual CT Connection, Helpful Debugging Tools

CT CONNECTION CHAPTER 3: ELECTRICAL INSTALLATION

3.2CT Connection

If the meter is connected directly to the current (up to 10 Amps max.), maintain the exact connection to avoid incorrect polarity.

When the meter is connected using the CTs, you must maintain the correct CT polarities. CT polarities are dependent upon correct connections of CT leads, and upon the direction the CTs are facing when clamped around conductors. The dot on the CT must face the line side; the corresponding secondary connection must connect to the appropriate input on the meter. Failure to connect CTs properly results in inaccurate power readings. If your meter is not reading power properly, it is more than likely the CT is incorrectly wired.

CTs are shorted if connected to the terminal block model DSP2 or 3 even if it is detached from the meter.

3.2.1Helpful Debugging Tools

Option 1: Isolating a CT Connection Reversal power reading

If your meter does not read the correct watts after installation, it almost always means that the CT’s have been wired in the wrong polarity. To check the polarity of the CT after the monitor has been installed, look at the single phase WATT readings to see that each of the readings are positive (assuming you are consuming power). If one of the WATT readings is negative, that particular phase CT is reversed.

To check the single phase WATT reading, press the Power button twice while the annunciator is positioned to WATTS. Then press the Phase/Next button to cycle through the phases. After connecting the polarity of the CTs, the WATT and VAR readings should be correct.

Option 2: Isolating a CT Connection Reversal using Voltage Readings

ZKW reading. It should be positive.

ZIf negative, reverse the CT wires on terminals 8 and 9.

ZConnect terminal number 6 potential. If KW decreases to about zero, reverse CT wires on terminals 10 and 11.

ZConnect terminal number 7 potential. If KW is one-third of expected reading, reverse CT wires to terminals 12 and 13.

3–6 EPM 5300 SERIES ADVANCED POWER METERS – INSTRUCTION MANUAL