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24 July 2017

New Megger DCM305E Earth Leakage Clamp Meter

Application shot Megger DCM305E Earth Leakage Clamp Meter, by Acutest

Megger DCM305E Earth Leakage Clamp Meter

DCM305E Earth Leakage Clamp Features:

  • 0.001 mA resolution
  • Up to 100 A AC
  • TRMS reading
  • Low pass filter to aid stability of readings
  • Auto, data & peak hold
  • Compare feature
  • 40 mm jaw
  • Auto back light
  • Auto power off (switchable)

DCM305E TRMS Current Ranges:

  • 6 mA, 60 mA, 600 mA, 6 A, 60 A, 100 A (AC)
  • Manual or Auto ranging
  • 0.001 mA resolution (6 mA range)
  • TRMS meters allow accurate measurements on both pure, undistorted, sinusoidal AC waveforms and non-sinusoidal AC waveforms which can contain triangles, pulse trains and other ragged waves


DCM305E Display Hold Features

Megger DCM305E Buttons and Screen Display

  • Data Hold
  • Freezes display readings
  • Auto Hold
  • Automatically freezes display readings
  • Peak Hold
  • Maintains highest current  reading


DCM305E Low Pass Filter:

  • Wide response (all frequencies)
  • 50-60 Hz response (low pass filter)
  • Low pass filters pass frequencies lower than cut-off frequency and attenuate frequencies above the cut-off frequency
  • Filters out high frequency harmonics to enable stable measurements
  • Cut-off frequency 100 Hz
  • Attenuation characteristic -24 dB / octave


DCM305E Compare Feature:

Megger DCM305E Buttons and Screen Display

  • Selectable limit values 0.25 mA, 0.5 mA, 3.5 mA
  • Clamp compares measured current with chosen limit value
  • Buzzer activates and display flashes when limit exceeded

Megger DCM305E Earth Clamp Meter


DCM305E Application Note Excerpt:

An earth leakage clamp, such as the Megger DCM305E, is generally a lightweight pocket size clamp meter designed to measure very small AC currents. They enable earth leakage faults to be detected and located without having to isolate and disconnect circuit wiring. In addition, most of these clamps are capable of performing AC current tests like any normal clamp meter. The measurement of earth leakage can be conducted on single or three phase systems.

RCD and RCBO operation
These two devices effectively monitor the currents flowing in the phase and neutral conductors. Under normal circumstances, these two conductors will have matching currents. An imbalance between the conductor currents will be detected by the RCD / RCBO sensing circuitry with the supply being disconnected by the RCD / RCBO.  A similar principle is utilised when using an earth leakage clamp to detect / measure earth leakage. An imbalance between the phase and neutral currents = leakage current.

Megger DCM305E Earth Leakage Clamp Single Phase Operation

DCM305E Earth Leakage Clamp Meter Single Phase Operation

Megger DCM305E Earth leakage clamp 3 phase + neutral operation

Megger DCM305E Earth leakage clamp 3 phase + neutral operation

While it is possible to simply clamp the instrument around the earth conductor this procedure will only indicate leakage current present in the earth conductor. This may not offer a true indication of earth leakage in the entire installation.