UNI-T UT278A+ earth ground clamp tester
Details
The UNI-T UT278A+ is part of the UT270+ series of clamp earth ground testers. It measures a grounding system without disconnecting the ground lines or driving test stakes into the soil, covering ground loop resistance up to 1200Ω with a resolution of 0.001Ω and leakage current down to 0.01mA. The sturdy housing makes it suitable for both indoor work and work at outdoor sites. It is a lower-cost alternative to the Fluke 1630-2 FC.
The measurement is based on mutual induction, meaning a coil in the jaw induces a voltage in the ground loop, and a second coil measures the resulting current. Unique to the UT278A+ in this series is that resistance and current appear on the same display. Digital frequency filtering keeps the two readings independent, and a "NOISE" indicator appears when the loop is too noisy for a reliable reading.
The jaw opening is 55x32mm, and the memory holds up to 300 groups of data at two measurements per second. An alarm warns when a value exceeds the set limit, and the included calibration loop with 1Ω and 10Ω references allows a check in the field.
Specifications
| Display resolution | 9999 counts, 4 digits |
| Leakage current range | 0 - 20 A |
| Leakage current resolution | 0.01 mA |
| Resistance range | 0.01 - 1200 Ω |
| Resistance resolution | 0.001 Ω |
| Measuring rate | 2 measurements/s |
| Clamp size | 55 x 32 mm |
| Other functions | Auto range, data hold, data access, visual/audible alarm setting, auto-off, jamming signal recognition |
| Display | 46 x 29 mm |
| Power supply | 4x 1.5 V batteries |
| Dimensions | 285 x 85 x 58 mm |
| Weight | 1.18 kg |
Accessories
The UT278A+ comes with:
- 4x 1.5V battery
- Calibration loop (1 Ω / 10 Ω)
- Carrying case
Pros and cons
- Measures earth resistance and leakage current at the same time
- Calibration loop included for field checks
- No external interfaces
Downloads
| UNI-T UT270+ series datasheet |  (277.54 KB) | Download |
| UNI-T UT276+ UT278+ user manual | (5.25 MB) | Download |
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