July 06, 2022 / by Danny Mavis

Ask any sparky, tradie, or facility engineer what’s the most important piece of information they can have when working with electric cabling or wiring, and they’re likely to tell you that it’s knowing whether the conductor has a current flowing through it, and if it does, how much. They know that overcurrents and unstable currents can lead to costly equipment damages and dangerous system failures. At their mildest, an instance of either can be a terrible inconvenience. At their worse, however, the results can be catastrophic.

The challenge has always been how to take precise, preventive electrical measurements without disconnecting an active circuit or making physical contact with it, neither of which are desirable approaches. Fortunately, there are handheld devices readily available that are designed for taking a multitude of current measurements; and you don’t have to interrupt a live circuit to use them.

Digital Clamp Meters Put Safety First

Make no mistake: safety is the most important factor when measuring the current flowing through an active circuit. Physically cutting into a circuit to take live measurements, however, even when possible, generally isn’t very practical, and it’s never safe. This is the advantage that a digital clampmeter designed to measure AC and DC currents affords electricians when they’re measuring current loads. Instead of making direct contact with the bare electrical conductor in a circuit, a clamp meter’s sealed, copper wound jaws only need to encircle it. By reading fluctuations in the magnetic field surrounding the conductor – a phenomenon called the Hall Effect – a clamp meter never needs to make contact with any part of the electrical system. The reading, however, is just as accurate as one taken by making physical contact with the conductor, only infinitely safer.

Modern clamp meter testers are designed to measure constant AC or DC voltages, inrush (surge) and transient (spike) states, as well as leakage currents. A user only needs to correctly indicate whether they’re reading from an AC or DC source, and with current sensing ranges up to 2,000 amps AC and 1,000 volts DC, they’re also suitable for taking readings from large load cables, as well as 3-phase power sources.

Depending on the type, nature, and even environment of the circuits to be tested, certain clamp meters will inherently be better suited for some jobs than others, but the underlying safety factor for testing and troubleshooting critical electrical systems, is consistent quality. They’re also capable of measuring more than just current too, and that’s why you’ll be surprised by how quickly a digital clamp meter can even take the place of your multimeter.

Testing clampmeters
source: bestadvisor.com

Clamp Meter Meets Multimeter

Although measuring current – the rate at which electricity flows past a point in a circuit – is what clamp meters are designed to do, top-of-the-line digital clamp meters are capable of doing much more. They not only measure current, but they also measure a range of parameters that would typically be performed by digital multimeters (DMMs), including:

· Voltage. The electrical force that drives electrical currents.

· Resistance. The forces opposing the movement of an electrical current.

· Frequency. The number of times an electrical current’s sine wave repeats.

· Capacitance. The amount of current stored in a circuit.

· Continuity. The unbroken flow of current through a circuit.

In fact, it’s because of this array of testing functionality that a clamp meter will sometimes be referred to as a digital clamp multimeter. It does the work of 2 instruments, with the benefit that it doesn’t need to make physical contact with any part of the system.

clampmeter check current in panel
source: housetechlab.com

Checking Temperatures With Clamp Meters

Combination multimeter clamp meter instruments are typically regarded as the best handheld analyzers for live circuit testing, but some models go even further. These testers include an even broader range of testing and troubleshooting tools that can be used beyond circuit analysis, including:

· Infrared thermometers for troubleshooting circuit hot spots;

· Type-K thermocouple connections for measuring conductor temperatures; and,

· Integrated thermal imaging that allows electrical staff to visually capture problems that the clamp meter may not detect.

It underlines how the all-in-one troubleshooting capabilities built into a high-quality DC clamp meter increase an organization’s ability to proactively identify and isolate electrical problems. Because the earlier an organization can take preventive action on them, the less likely they are to become larger problems.

Checking Temperatures With Clamp Meters
source: ubuy.vn

Clamp Meter With Bluetooth

When you buy clamp meter instruments, you also want to make sure they offer a solid suite of support tools that’ll let the electrical team get the most out of the data obtained from every circuit test. Clamp meters equipped with Bluetooth connectivity can be operated and monitored from a safe distance by either a smartphone or a tablet, and all of their results are logged and stored for trend analysis.

As an instrument whose primary function is to allow electricians to take preventive measures, Bluetooth connectivity is undoubtedly one of a clamp meter’s best attributes.

Clamp Meter With Bluetooth
source: hioki.com

Clamp Meter Jaw Size

Because the jaws on an electric clamp meter are its main measuring apparatus, and because they shouldn’t come in contact with the circuit being measured, their size is one of the meter’s most important features. A conductor that can’t be positioned in the centre of the jaws, or is too large for the jaws to completely close around, can’t be measured accurately.

Ultimately, facility engineers and electricians need to ensure that the current clamp meter they’re using has appropriately sized jaws for the maximum diameter of the conductors they’ll be measuring. Oval-shaped, hard-type jaw openings ordinarily vary between 13mm and 55mm, while flexible-type opening diameters extend to as much as 110mm.

A variety of different jaw shapes and thicknesses meant to accommodate double-wired or closely spaced conductors are also available across the various jaw sizes. Ultimately, the type of measuring that needs to be done is going to determine the type of jaws that are needed, but there are jaw size/voltage rating combinations available for every circuit testing contingency.

Clamp Meter Jaw Size
source: electronicsweekly.com

The Final Word

At the end of the day, accurate and preventive circuit testing is the only way to ensure that electrical systems are operating as intended, and free from any problems that could prevent them from operating as intended. The real challenge, however, is being able to conduct that testing in the safest, and least disruptive manner possible.

A full-featured, digital clampmeter can be an invaluable piece of equipment when it comes to taking the kind of precise measurements needed to keep systems performing at their best at all times. They’re not tremendously expensive instruments as far as the test equipment is concerned, but they’re one of the best investments that any company or electrician can make.