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Portable 3-phase watthour meter tester

The MT-1/NT3 is the smallest portable 3-phase watthour meter tester available today and weighs only 6 lb! It is an ideal tool for field-testing and periodic sampling. No setup wiring is needed. A complete test is done within a few minutes!
The MT-1/NT3 can test commercial and industrial 3-phase meter forms 12S, 14S, 15S and 16S along with single-phase meter forms 1S and 2S.
The MT-1/NT3 comes with a calibration report certifying measurement accuracy over its entire 36-point operating range using a primary standard traceable to NIST.
The MT-1/NT3 can be set to test all 3 phases simultaneously in one step (Mode Preset-quick) or set to do a full test consisting of the 3 phases simultaneously followed by each element separately (Mode Preset-full).
The MT-1/NT3 also has reverse flow testing capability for net metering installations.
SKU: NT3 Category:


Three Built-in 50A Current Synthesizers (Phantom Load)

  • Simulates active and reactive loads.
  • Regulated test currents up to 50A.

Built-in 3-phase Watthour Standard

  • True 3-phase watthour standard.
  • Stable accuracy within the specified temperature operating range
  • Comes with a complete calibration report certifying measurement accuracy over its entire 36-point operating range using a reference standard traceable to NIST.

Easy to Use

  • Twist and lock removable tab can be placed without tools at 5, 6 or 9 o’clock.
  • Handheld remote control with its intuitive menus.
  • Deadfront design for safer operation.


Compatible Meters
Form 1S, 2S, 12S, 14S, 15S, 16S
Class 100, 200, 320*
Test Socket
Input Voltage 100 – 600VAC
Line Frequency 58 – 62Hz
Power Consumption 75VA (maximum)
Circuit Breakers 3 x 1A (press-to-reset mechanism)
Current Synthesizers
Adjustable Current 1 to 50A
Phase Angle Unity and 60° Lag
3-phase Watthour Standard
Typical Accuracy ±0.02%
Guaranteed Accuracy ±0.05%
Operation -4° to 140°F (-20° to 60°C)
Storage -4° to 140°F (-20° to 60°C)
Humidity 5% to 95% (non condensing)
Physical Dimensions
Test Socket (Diam. x D) 6.9” x 7.7”
Remote Control (HxLxD) 8.3” x 3.9” x 1”
Carrying Bag (HxLxD) 11” x 11” x 8”
Test Socket 6.0 lb
Remote Control 0.6 lb
Overall with Carrying Bag 8.7 lb
Parts and Labor 2-years limited**

*An adapter may be required depending on the meter installation.
*Only applicable to units shipped to Canada or USA. 1 year warranty for other countries.