The microprocessor-based metering device acceptance test is a multi-part verification that a new or reconditioned digital meter has been installed correctly, is mechanically sound, and will function as intended once energized. NETA ATS-2025 7.11.2 organizes the test into six sections: Identification (manufacturer, model number, serial number, rated control voltage, meter type and function, firmware and software revision levels); Visual and Mechanical Inspection (physical damage, mounting, case integrity, display); Analog Input Measurement Verification (accuracy of voltage and current signals being fed to the meter); Auxiliary Input and Output Features (relay function, communications, optional modules); Post-Energization Verification (live readings under load, confirming the meter is displaying what the circuit actually carries); and Ambient (temperature and humidity at test time). The test set documents each section and flags any discrepancy before the meter is placed into service.
A microprocessor-based meter is the eyes of a protection scheme, an energy accounting system, or a power-quality monitoring program. If it has been misconfigured, miswired, or shipped with the wrong firmware or software release, it will report incorrect values for voltage, current, power, or fault conditions - mistakes that can cause protective relays to misoperate, energy billings to be wrong, or asset condition to be undetected. Running a structured acceptance test before the meter is energized catches those errors in the shop, rather than in the field where they cause operational or financial harm. The test also serves as a baseline: any future deviation in the meter's readings or function can be compared against this acceptance record.
Acceptance: performed before a new or reconditioned microprocessor-based metering device is first connected to its signal inputs and powered up, and includes the full identification and mechanical sections plus live post-energization checks under whatever steady-state load is available in the acceptance-test environment (or, if the meter is being installed into an energized circuit, the functional verification is deferred until the meter is in service and can see actual system loads, after which the acceptance data is completed with those live readings). Maintenance: while the periodic recertification of a meter's accuracy is a calibration or conformance function separate from acceptance testing, a re-check of the identification and mechanical sections may be requested after maintenance work or as part of a rebuild program.
With the meter isolated from its signal sources and de-energized, the technician begins by recording the nameplate data (manufacturer, model, serial number, control voltage rating, meter type and function) and comparing it against the specifications or purchase order to confirm the right unit is being tested. The case, display, terminal blocks, and front-panel indicators are inspected for physical damage or loose parts. If the meter has a firmware or software version display, those version numbers are captured per NETA ATS-2025 7.11.2.A.5. Before the meter is powered, steady-state AC voltage and current sources (or simulators) corresponding to the meter's input ranges are connected to its voltage and current terminals, and any auxiliary inputs or outputs (relay contacts, pulse output, communications port) are also connected to their test apparatus. Once the meter is energized, its display is observed to confirm it starts up normally, the software or firmware version matches the expected release, and the live readings on the display match or closely track the input signals being supplied to it. If the meter has been shipped with an unexpected firmware version, has a mechanical defect, or displays readings that do not correspond to the input signals, the issue is documented and resolved before the meter is released for installation.
Under the Identification section: manufacturer, model number, serial number, rated control voltage, meter type and function, and firmware and software revision numbers as found on the device. Under Visual and Mechanical Inspection: the condition of the case, display, terminal blocks, and any visible wiring or modules, and confirmation that the meter is mounted securely. Under Analog Input Measurement Verification: the applied test voltage and current, and the meter's corresponding display readings, for each input range or channel being tested. Under Auxiliary Input and Output Features: any relay, pulse output, or communications function that the meter possesses and whether each responded correctly to a test signal. Under Post-Energization Verification: the type of load or signal applied when the meter was powered up, the readings displayed (in volts, amperes, watts, or other units appropriate to the meter type), and any ambient temperature and humidity at the time of test. Any anomalies, deficiencies, or follow-up actions are recorded in the Comments section.
NETA ATS-2025 7.11.2 requires that the identification data (manufacturer, model, serial, firmware and software revisions per section 7.11.2.A.5) match the purchase specification and the equipment tag or nameplate, confirming the correct unit is in place. The Visual and Mechanical Inspection section must show no physical damage that would affect operation. The Analog Input Measurement Verification section requires that the meter's displayed readings fall within the manufacturer's own published tolerance for accuracy - NETA ATS-2025 sets no universal numeric percentage for this criterion; the tolerance is whatever the specific meter's accuracy class or specification sheet states. Under Post-Energization Verification per section 7.11.2.B.3, loads present and readings observed must be captured and must be consistent with the input signals being supplied, confirming the meter is functioning. Any reading that falls outside the meter manufacturer's published accuracy tolerance, any mechanical defect, or any auxiliary function that does not respond to a test signal is cause for repair, replacement, or further investigation before the meter is accepted and placed into service. See the purchased standard for the complete text and any function-specific or manufacturer-specific acceptance criteria.
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