Electrical Tester Contractor edition
October - November 2017
Earth leakage clampmeter trounces nuisance tripping

Earth leakage clampmeter trounces nuisance tripping

12 October 2017

The DCM305E is easy to use and has been designed to provide accurate results even in difficult conditions. It offers true RMS (TRMS) measurement, which means that readings are unaffected by distortion in the supply waveform, and has a built-in low-pass filter that greatly improves the stability of results on circuits where high levels of harmonics or electrical noise are present.

When investigating nuisance tripping, the DCM305E allows earth leakage currents to be measured quickly, accurately and safely, since no physical connection to the circuit under test is needed. The measurements show immediately whether the problem is an overly sensitive protective device (RCD or RCBO), or an issue related to excessive earth leakage current caused, for example, by cable deterioration.

As a further aid to fast and convenient operation, a valuable compare function is provided, which has three preset leakage limits: 0.25, 0.50 and 3.5 mA. When this function is enabled, the instrument gives a visual indication and an audible warning when the preset limit is exceeded.

To facilitate its use in wider applications, the DCM305E offers six current ranges, from 6 mA up to 100 A, with a choice of auto-ranging or manual range selection. Auto hold, data hold and peak hold functions are available on all ranges. These functions are particularly useful when performing measurements in locations where access is limited.

The Megger DCM305E earth leakage clampmeter is a compact instrument that features rugged construction to ensure that it can withstand the rigours of regular on-site usage. It has 40 mm jaws suitable for use with both insulated and uninsulated conductors, and incorporates an integrated hand barrier for enhanced safety. Results are shown on large backlit 6000-count digital display, which also includes an analogue bargraph to aid trending.

For more information on the DCM305E click here

For a presentation making sense of earth leakage click here