Common uses for clamp meters

Clamp meters are intuitive, straight-forward tools that can measure electrical current quickly. They’re common among electricians and technicians since they can save time and effort. Clamp meters are often preferred over other similar tools for their safe and easy design. Whether you’re an apprentice, an avid DIY-er, or just curious about measurement tools, it’s worthwhile learning about the design and uses of a clamp meter.

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What is a clamp meter?


Clamp meters are extremely useful tools used to measure current. You’ll find these devices in the toolboxes of many electricians and electrical engineers. The hand-held device combines the functionality of a multimeter with a current sensor.


The current sensor is located within the clamp, which resembles a pincher at the top of a digital meter. A release lever opens the clamp so that the technician can place the clamp around a conductor, such as a wire or cable. Through this simple method, one can measure the current without going through the trouble of disconnecting the circuit.


Clamp meters have a lot in common with digital multimeters. Knowing the differences between the two will help you understand when it’s appropriate to use one over the other.

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Clamp meters versus multimeters


Multimeters allow you to measure several things: voltage, capacitance, continuity, resistance, and current. Most multimeters let you measure up to 10 amps of current. Clamp meters, on the other hand, can measure a much higher number of amps. The lowest measure up to 100 amps, but some can measure up to 2,500 amps.


Measuring current with a multimeter takes several steps. This instrument measures the current in series through its jacks. You start the measurement process by powering down the equipment that you want to measure. This allows you to safely connect the multimeter to the circuitry. Once the multimeter is properly connected, you turn the power back on. At this point, you’ll be able to read the electrical current measurement on the multimeter.


Although it’s nice to have the option to measure current with a multimeter, these extra steps are time consuming. It gets in the way of the workflow and decreases efficiency. For that reason alone, many people prefer a clamp meter when measuring current.


There’s also the safety aspect. It can be dangerous to open a circuit. Any time you make physical contact with a test point, you’re at risk of electrical shock. Because a clamp meter lets you read the electrical current without opening the circuit, it’s a much safer and simpler option. Many technicians prefer them for this reason, as well.


When you have a clamp meter in your toolbox, you can read a current in a jiffy. All you need to do is clamp the device around a conductor and you’ll get your reading. There’s no need to waste time and energy on extra steps.


In addition to reading the current, modern clamp meters offer a lot of other features like those in a multimeter. Many are capable of measuring resistance, voltage, and continuity. Clamp meters are preferred by many electricians because of their flexibility in addition to their convenience. Since they’re safer to use — and can read a higher ranger of currents — they bring a lot to the table.

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How do clamp meters work?


A clamp meter works by detecting and measuring the magnetic field generated by a current. The clamps are made of ferrite iron, surrounded by the safe, hard plastic on the outside. When the instrument is clamped around a conductor, the ferrite iron interacts with the magnetic field to provide the measurement of the current.


Most modern clamp meters are digital. When the tool is clamped around the conductor, the digital display will show the measurement reading. Many instruments have a button that will freeze the measurement on the screen for your convenience. If that's not available, it’s also simple to hold the device with your non-dominant hand to write down the reading with your dominant hand.


Originally, clamp meters were made just to measure electrical current. But their accuracy, simplicity, and convenience made them so useful, that manufacturers began to optimize clamp meters by adding in more features.


When to use a clamp meter


Clamp meters come in handy any time a project calls for checking the current of a circuit. This makes for a wide range of potential uses. Below are some of the most common.


Troubleshooting A clamp meter is an essential tool for testing equipment. As electrical equipment continues to advance with each year, electricians must keep up with changes. That means knowing how to perform troubleshooting quickly and safely through testing procedures.


Whether testing a plant or a piece of machinery, the quick functionality and safety of a clamp meter is ideal. When troubleshooting something like this, a technician often needs to be able to test the electrical current as well as voltage. The versatility of a modern clamp meter is perfect for this situation, as it can read both measurements.


Electrical installations Measuring and monitoring electrical current is, of course, essential in electrical work. As such, a clamp meter is used across several contexts in electrical installation. They come into play when installing residential electrical systems, as well as commercial and industrial electrical systems. They’re also useful when building and repairing industrial equipment and machinery.


Supervise apprentice electricians When a new electrician is in training, it’s essential to be aware of all conditions on the job site. A clamp meter is often used to monitor the system, and to supervise the apprentice as they work to install or update equipment. At the end of an installation, a clamp meter allows for a quick and final circuit test.


Repairs and maintenance It’s common to see a clamp meter in an HVAC technician’s toolbox. These specialists spend lots of their time performing regular maintenance and checkups on HVAC systems. In this process, it’s essential to get quick and accurate readings on electrical current, resistance, and volt. The right clamp meter is a great all-in-one tool that serves this purpose well.


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Phil Wiseman

Phil Wiseman

Phil Wiseman is Chief Marketing Officer at Alliance Calibration. He earned a B.S. in Chemical Physics from Centre College. Phil is an ASQ Certified Quality Auditor and ASQ Certified Manager of Quality/Organizational Excellence.

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