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Arm-type Personal Electric Alarm — Higher Antenna for Noisy Environments

2026年05月12日

When the field is dense, the bigger antenna wins — here is when to choose arm-type over wrist-type.

When Wrist Is Not Enough

In a transformer yard or 110 kV switchgear room the electric field is dense and three-dimensional. A wrist-mounted alarm with a small antenna can show ambiguous response — alarming once, then silent as the wearer turns. An arm-type personal electric alarm like the A187 has a larger antenna mounted higher on the body — the response stays unambiguous.

1. Bigger Antenna = Sharper Threshold

The A187's antenna is 2.5 × the area of the wrist version. Result: cleaner threshold, less directional dependence, fewer false negatives in dense fields.

2. Higher Body Position

Mounted on the upper arm, the antenna sits closer to head height — the part of the body most likely to enter an HV field first when reaching upward. Wrist-mount units protect the hand; arm-mount units protect the head.

3. Same Detection Envelope

  • 40 V to 500 kV.
  • Five sensitivity steps.
  • Audible + vibration + LED simultaneous.

4. Field Use Discipline

  1. Mount on the dominant arm, outside any conductive PPE.
  2. Self-test before EVERY shift.
  3. Confirm on a known-live reference (substation test station).
  4. Sensitivity step matched to task voltage.

5. Battery

CR2032, 2-year life, slide cover replacement. Low-battery LED at 20 % remaining.

6. Strap and Comfort

Velcro nylon strap with silicone underlay — stays put under coveralls and rain gear. Adjustable from 22 to 38 cm upper-arm circumference.

EK Recommendation

For substation operators, transformer yard crews and HV switchyard work the A187 arm-type personal electric alarm is the upgrade from wrist-type. Talk to EK service teams for site-specific sensitivity calibration.