UNI-T UT278A+ earth ground clamp tester

The UNI-T UT278A+ is part of the UT270+ series of clamp earth ground testers. It can quickly and safely measure a grounding system without disconnecting the ground lines or driving test stakes into the soil, which makes it usable indoors, in substations, on pylons and on paved sites. It measures ground loop resistance up to 1200Ω with a resolution of 0.001Ω, while also measuring leakage current with a resolution of 0.01mA.

The measurement is based on mutual induction: a coil in the jaw induces a voltage in the ground loop and a second coil measures the resulting current, from which the resistance is calculated. Unique to the UT278A+ in this series is that it shows both the measured resistance and current on the same display. The leakage current is measured independently from the earth resistance through digital frequency filtering, so the two readings do not affect each other. Furthermore, the tester recognises interference automatically and shows a "NOISE" indicator when the loop is too noisy for a reliable reading.

The jaw opening of the clamp is 55 x 32mm. Its memory is capable of storing up to 300 groups of data, and it has a measuring time of 2/s. Moreover, an adjustable alarm warns audibly and visually when a value exceeds the set limit, and a calibration loop with 1Ω and 10Ω references is included so the tester can be checked in the field. Finally, the sturdy housing makes the tester suitable for outdoor work, and the auto-off function ensures the battery is not being drained needlessly.

Specifications

Accessories

The UT278A+ comes by default with:

• 4x 1.5V battery
• Calibration loop (1 Ω / 10 Ω)
• Carrying case

Downloads

UNI-T UT270+ series datasheet	(277.54 KB)	Download
UNI-T UT276+ UT278+ user manual	(5.25 MB)	Download