GE EPM 5350 Chapter Electrical Installation, Connecting the Current Circuit, CT Connection

CHAPTER 3: ELECTRICAL INSTALLATION

CHAPTER 3

ELECTRICAL INSTALLATION

3.1: Connecting the Current Circuit

Install the wiring for the current at 600V AC insulation as a minimum. The cable connector should be rated for 6 Amps or greater and have a cross-sectional area of 16 AWG minimum.

Mount the current transformers (CTs) as close as possible to the meter for best accuracy. The following table illustrates the maximum recommended distances for various CT sizes, assuming the connection is via 16 AWG cable.

CT Size	Maximum Distance (CT to Meter)
2.5 VA	10 FEET
5.0 VA	15 FEET
7.5 VA	30 FEET
10.0 VA	40 FEET
15.0 VA	60 FEET
30.0 VA	120 FEET

Table 3.1: CT Size and Maximum Distance

WARNING:

DO NOT leave secondary of the CT open when primary current is flowing. This causes high voltage that

will overheat the secondary of the CT. Use a shorting block on the secondary of the CT.

3.2: CT 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.

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

HELPFUL 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.

GE Industrial Systems 5300P Advanced Power Meter 7