What Is A Clamp Meter And How Does It Work?

The clamp meter, often referred to as the Tong Tester, is a device used to measure current without putting it in series to a circuit. This equipment is simple to operate and can be used to measure a live conductor without endangering it or disrupting power.

What is a clamp meter?

It is a tool used to quickly and safely measure current. Without test leads, it is particularly effective at measuring current. All we need to do to measure current is insert a wire into the clamp meter‘s claws. A magnetic field is produced when a conductor is subjected to current. To provide a reading of the associated current, this device aids in detecting the magnetic field. Although most technicians carry combination clamp metres that also serve as their multimeters, dedicated clamp metres only measure current (like with the popular Meco clamp meter pieces). The main advantage is that we can do measurements quickly and safely without stopping the current flow or requiring test leads.

How does a clamp meter work?

For no-contact alternating current (AC) current measurements, clamp metres use the magnetic induction theory of operation. The magnetic field created by the flow of electric current down the wire is detected by the clamp meter’s internal current transformer, which converts the measurement to the matching AC current value. This is the fundamental idea behind the working of clamp metres.

Why are clamp meters popular?

The two main reasons why clamp metres have gained popularity as instruments are:

Safety — With clamp metres, electricians can avoid the traditional procedure of severing a wire and placing a meter’s test leads into the circuit to measure the in-line current. During a measurement, the clamp meter’s jaws don’t have to come into contact with the conductor.

Convenience — It is not essential to turn off the circuit that is carrying current during a measurement, which greatly improves efficiency.

What are clamp meters used for?

Industrial machinery, controls, residential, commercial, and industrial electrical systems, as well as commercial and industrial HVAC, all use clamp metres. They are mostly employed for:

Service: On-demand maintenance and repair of current systems.

Installation: Troubleshooting installation issues, conducting final circuit testing, and supervising trainee electricians as they install electrical equipment are all part of the installation process.

Maintenance: To carry out planned maintenance, proactive maintenance, and system troubleshooting.

The types of clamp meter

There are three varieties of clamp metres:

Current transformer clamp meters:

For current transformer measurement, two ferrites iron clamps are employed. These clamps have individual copper coil covers. They come together to create a magnetic core, whose surface is used for the measurements.

The electromagnetic principle states that a current in a conducting material result in the formation of magnetic flux. Magnetic flux, a unit of charge, can be used to measure the magnetic field. It is denoted by the Greek letter Phi.

Meco 3150 Digital AC Clamp Meter 1000 A 750 V

Meco 4671 (Resistance Range : 40–400°C) Digital Leakage Current Tester

Hall Effect clamp meters:

These can measure both AC and DC signals. When the clamps are closed around the conductor in a Hall Effect clamp metre, the current flowing through the conductor creates a focusing magnetic field.

Since the Hall Effect Clamp metre can concentrate DC magnetic fields, it can also measure DC. When measuring the current, these clamp metres need to be zeroed. It is essential to prevent errors brought on by the magnetic field of the Earth or any other nearby magnetic field sources.

Fluke I30S AC/DC Current Clamp

Flexible clamp meters:

These employ a Rogowski coil and measure ac only. They are good for measuring in tight spaces.

FLIR Flexible Clamp Meter CM57

Conclusion

Follow the steps listed below to learn how to use a clamp metre:

1. Connect the current probe and metre to supply the device with power.
2. Choose a wider range of values to prevent any circuit damage, and then progressively lower the scale reading as the current value decreases.
3. Make sure to attach the probe’s elastic pipe where the conductor is located and that the distance between the conductor and the probe is greater than or equal to 2.5 inches.
4. Turn on the ammeter now and measure the current across each cable in the winding. Only one reading will be measured at a time in this case.
5. Find the reading on the LCD display.

Modern clamp metres offer more measuring functions, more precision, and in certain cases, specialised measurement features than their predecessors, which were designed as a single-use test tool. Most of the fundamental capabilities of a digital multimeter (DMM), including the capacity to detect voltage, continuity, and resistance, are present in modern clamp metres.

Before purchasing, visit Industry Buying to learn more about the clamp meter price ranges.