The model GM-250 is the most advanced high voltage ground monitor on the market today because:

  • Pilotless or pilot wire operation.
  • Continuity monitor (45 ohm trip resistance)
  • Time delay (250 mS). Reduces nuisance tripping.
  • Immune to high and low voltage conditions. (+10%, -30%)
  • Immune to DC and AC stray currents.
  • Easy installation and maintenance.
  • Transient protection on all inputs and outputs.
  • Approved to work with cable lengths to 10,000 feet.
  • Saves cable cost and repairs.
  • Only M.S.H.A. -accepted high-voltage pilotless ground monitor.
Dimensions: 6″W x 7.75″H x 8.5″D
(152.4mm x 196.9 x 215.9)
Weight: 11.25 lbs (5.1 kg)
Certifications: MSHA
Enclosure Rating: Industrial Powder Coated Aluminum
Main Assembly Installation: Flush or Flange Mount
Operating Voltage: 120 VAC
Current Consumption: 250 mA
Operating Temperature: -20 to 70C
Humidity: 0 to 90% R.H.
Phase Voltage Filters: 7.2 kV, 15 kV, or 25 kV
Trip Resistance: Adjustable up to 75 ohms
Trip Delay: 250 ms
Reset Mode: Auto
Transmitter Frequency: 1000 Hz +/- 1%
Transmitter Output Current: 200 mA
Outputs: (1) Normally open or normally closed contact relay
Contact Relay Rating: Form C – 120 VAC @ 10 A or 240 VAC @ 5 A
Contact Operating Mode: Fail Safe
Display: LED Indicators, Analog Current Meter
Backup Battery: No
Test Feature: Yes
Option: Blocking Inductor – prevents parallel earth pass of signal
High Voltage phase filter for pilotless operation
Warranty: 90 Days