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Troubleshooting PH2 and PH ERR Faults on 3-Phase High-Leg Delta Systems

Use the following steps to troubleshoot PH2 and PH ERR faults on 3-phase high-leg delta systems.

A PH2 or PH ERR fault may occur when a Trumeter meter is connected to a 3-phase high-leg delta system, including 120/240 V high-leg delta configurations.

These errors can be related to the system configuration, phase connections, voltage measurement range, or incorrect interpretation of AC and DC measurements.

Use the steps below to verify the electrical system and meter connections before troubleshooting the meter. 

Understanding High-Leg Delta Systems

A 120/240 V high-leg delta system differs from a standard 3-phase system because the phase-to-neutral voltages are not equal.

A typical system may measure approximately:

Measurement

Typical Voltage

Phase A to Neutral

120 V AC

Phase B (High Leg) to Neutral

208 V AC

Phase C to Neutral

120 V AC

Phase to Phase

240 V AC

The high leg is typically Phase B, but always verify the actual system before connecting the meter.

Important: Do not assume phase identification based only on conductor position or labeling. Verify each phase with an appropriate measurement device before wiring the meter.

 1. Verify the Electrical System

Before changing the meter configuration, measure the actual voltage at the installation.

Verify:

  • Phase-to-phase voltage
  • Each phase-to-neutral voltage
  • Which phase is the high leg
  • Whether the measured signal is AC or DC
  • Each phase is connected to the correct terminal.
  • Neutral is connected where required.
  • The high leg has been correctly identified.
  • Supply power is connected to the correct terminals.
  • All connections are secure.
  • Display as zero
  • Produce an unstable reading
  • Produce a reading that differs from a higher-resolution reference meter

          Confirm that the measured values are within the supported input range of the Trumeter model.

          2. Verify Phase Connections

          Compare the meter wiring with the applicable Trumeter wiring diagram.

          Confirm that Incorrect phase or supply connections may result in a PH2 or PH ERR indication or may prevent the meter from powering on.

                    3. Confirm AC or DC Measurement

                    Do not assume the meter automatically detects whether the input is AC or DC.

                    Verify the type of voltage being measured and confirm that the meter and its configuration support that measurement.

                    An AC measurement interpreted as DC, or a DC measurement interpreted as AC, can result in unexpected readings or troubleshooting conclusions.

                    4. Check the Minimum Measurable Voltage

                    If the meter communicates or powers correctly but displays an unexpected value at low voltage, verify that the signal is within the measurable range.

                    Every meter has limits to its measurement range and resolution. Signals below the minimum measurable voltage may:

                          A low-voltage reading should not automatically be interpreted as a meter fault.

                          Refer to the specifications for the applicable Trumeter model to confirm its minimum measurable voltage and resolution.

                          5. If the Meter Does Not Power On

                          If the display does not power on after installation:

                          1. Disconnect power before changing the wiring.
                          2. Verify the meter's required supply voltage.
                          3. Confirm that supply power is connected to the designated supply terminals.
                          4. Verify phase and neutral connections against the wiring diagram.
                          5. Confirm that the measured supply voltage is within the meter's specified operating range.
                          6. Reapply power and verify operation.

                                      Warning: Do not move conductors or modify wiring while the circuit is energized. Follow applicable electrical safety procedures for installation.

                                      PH2 or PH ERR Still Displayed?

                                      If the electrical system and wiring have been verified but PH2 or PH ERR continues to display, record the following information before contacting Trumeter Technical Support:

                                      • Trumeter product and model number
                                      • Supply configuration
                                      • Phase-to-phase voltage measurements
                                      • Phase-to-neutral voltage measurements
                                      • Identification of the high leg
                                      • AC or DC measurement type
                                      • Wiring configuration
                                      • Error displayed
                                      • Photos or diagram of the meter connections

                                                        Providing the actual measured voltages and wiring configuration can help Technical Support determine whether the fault is related to the electrical system, meter configuration, measurement limits, or another condition.