Giving Your Ground Tester a One-Two Punch

Keep in mind that many electrical tests, and the required instrumentation, complement each other. What one test doesn't reveal, another will. Don't be satisfied with guesswork or negative evidence. Look around the fringes of your application to see if there's more than a single designated test can tell. The benefits can pay off!

An interesting new example is the use of the DCM300E Earth Leakage Clamp Meter in conjunction any Megger® Ground Tester. The DCM300E conveniently clamps over a ground rod or conductor, and within seconds, digitally indicates the presence of any current flowing to ground. True, there shouldn't be any, but you'll be surprised at how often there is. Unbalanced electrical systems can send a leakage current of anywhere from a few milliamps to several amps, more or less constantly, to earth via the ground wires and rods. The test operator wants first to protect himself from any unpleasant surprises caused by contacting several amps of leakage current unaware. The Earth Leakage Clamp Meter clamps safely around rod or conductor to sense field influence without actual contact, warning the operator before any physical contact is made with the grounding system.

Once this determination is made, the benefits don't end there! At the least, you are protected from unjust recriminations when power quality problems (e.g., nuisance tripping) persist after adequate grounding has been installed. At best, the operator may be revealing a costly and dangerous condition that hadn't been suspected, and becomes a hero!

This one-two combination doubles both your protection and capabilities...and it's easy. The DCM300E fits in a shirt pocket and is simple to operate. Its range significantly surpasses that of an ordinary clamp-on... measuring down to as little as 0.01 mA to detect small leakage currents which may be symptomatic of large power quality problems, and up to 300 A for more routine measurements. And it has a unique analog bar graph to observe the time dynamics of current flow, a critical function in isolating the source of a problem.

When performing a ground test, have you been "bitten" by a "live" ground, or are you concerned about the possibility? Have there been electrical disturbances, unsatisfactory equipment operation, or perplexing inconsistencies in the electrical system? You will be interested to learn of the benefits that this handy addition to the tool kit can bring.