Typical sources of test errors
Typical sources of accuracy verification testing errors include:
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Loose connections of voltage or current circuits, often caused by worn-out contacts or terminals. Inspect terminals of test equipment, cables, test harness and the meter under test.
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Meter ambient temperature is significantly different than 23 °C (73 °F).
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Floating (ungrounded) neutral voltage terminal in any configuration with unbalanced phase voltages.
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Inadequate meter control power, resulting in the meter resetting during the test procedure.
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Ambient light interference or sensitivity issues with the optical sensor.
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Unstable power source causing energy pulsing fluctuations.
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Incorrect test setup: not all phases connected to the reference device or the energy standard. All phases connected to the meter under test should also be connected to the reference meter/standard.
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Moisture (condensing humidity), debris or pollution present in the meter under test.