A clamp meter is an electrical test tool that combines a basic digital multimeter with a current sensor. Clamps measure current such as AC current, AC and DC voltage, resistance, continuity, and, with some models, DC current, capacitance, temperature, frequency and more. Due to the hinged jaw, this tool allows the user to clamp the jaws around a wire, cable or other conductor at any point in an electrical system, then measure the current without disconnecting it. True RMS measurements, this tester typically measures to the nearest 10th of a unit making them perfect for electrical work such as repairing, installation and maintenance. Originally created as a single-purpose test tool, modern clampmeters offer more measurement functions, greater accuracy and sometimes specialised measurement features. Today’s clamp meters include most of the basic functions of a digital multimeter, such as the ability to measure voltage, continuity and resistance. Who uses them? Industrial maintenance technicians Control technicians Electricians – in-house and contractors Facilities, building maintenance and HVAC technicians Service organisations What are they used on? Industrial equipment Industrial controls Electrical systems Commercial/industrial HVAC Why are Clamp meters so popular? Safety: Clamp meters allow electricians to bypass the old-school method of cutting into a wire and inserting a meter’s test leads into the circuit to take an inline current measurement. The jaws of a clamp meter do not need to touch a conductor during a measurement. Convenience: During measurement, it is not necessary to shut off the circuit carrying current—a large boost in efficiency. They are primarily used for: Service: Repair existing systems on an as-needed basis. Installation: Troubleshooting installation problems, perform final circuit tests, and supervise apprentice electricians while installing electrical equipment. Maintenance: Perform scheduled and preventative maintenance and system troubleshooting.