You’ve probably come across the term “clamp meter” several times. But what is it? What does it do? And who is it for? 

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What is a True RMS Clamp Meter?


Fluke-325-clamp meter


You’ve probably come across the term “clamp meter” several times. But what is it? What does it do? And who is it for? 


Let’s define a clamp meter first. A clamp meter is an electrical tool that’s basically a combination of the basic digital multimeter and sensor. This device has jaws that allows an electrical conductor to be clamped around it. As mentioned by Fluke website, clamps measure current while the probes measure voltage. Simply put, it measures electrical current without physical contact. 


Technicians are the ones who mainly use true rms clamp meters. It allows them to clamp the jaws around a wire, cable or other conductor at any point in an electrical system, then measure current in that circuit without disconnecting/deenergizing it.


fluke clamp meter

To get to know the device better, let’s look into its anatomy. 


  1. Current-sensing jaw
  2. Tactile barrier (to protect fingers from shocks)
  3. Hold button: Freezes the display reading. Reading is released when the button is pushed a second time. 
  4. Dial (aka rotary switch)
  5. Display
  6. Backlight button
  7. Min Max button: On first push, display shows maximum input. On subsequent pushes, minimum and average inputs are shown. Works in current, voltage and frequency modes. 
  8. Inrush current button
  9. Zero button (yellow): Removes dc offset from dc current measurements. Also serves as dial’s shift button to select yellow functions scattered around the dial
  10. Jaw release lever
  11. Alignment marks: To meet accuracy specifications, a conductor must be aligned with these marks
  12. Common input jack
  13. Volts/ohm input jack
  14. Input for flexible current probe


The good thing about modern clamp meters are more measurement functions, and better accuracy. It includes basic functions of a digital multimeter i.e., measuring voltage, continuity, and resistance. 

So, why should technicians invest in a clamp meter? Two things: safety and convenience. Gone are the days when electricians have to manually cut into a wire and insert the meter’s test leads into the circuit to measure. Due to its “no contact” feature, measuring current is so much safer and more efficient. 

This well-structured device is also used in repairing electrical systems, installing electrical equipment, troubleshooting installation problems, performing final circuit tests, and maintaining. 

For all our technicians, a true rms clamp meter proves to be a definite bang for your buck.  

See our list of True RMS Clamp Meter: