A clamp meter is primarily built for measuring current (or amperage), while a multimeter typically measures voltage, resistance, continuity, and sometimes low current. Nowadays, some clamps also include the measuring abilities of basic multimeters, and, likewise, some test meters allow for the attachment of an amp clamp (such as the Fluke iflex).
The main clamp meter vs multimeter difference is that they can measure high current, while multimeters have higher accuracy and better resolution. However, an amp clamp multimeter somewhat thwarts this generalization in that they may also come with pretty good accuracy specs on voltage and resistance.
If you’re into electronics, having a DMM is a no-brainer, since the higher resolution/accuracy in a good one allows you to see minute changes at the milliohms, millivolts and even micro-amps level. With an amp clamp, you might get down to the hundredths of a unit, or tenths, as opposed to thousandths and millionths. But with many electrical tasks, the former will be fine.
What They Look Like
Architecturally, clamp meters are just that; non-contact test tools that clamp around a cable to determine amperage inductively. They are safe, quick and convenient. Multimeters that can test current do so ‘in series’ within the circuit, such that you need to break it to allow current to flow directly through the meter. This is both time-consuming and potentially dangerous.
They also only usually test to 10A – or up to 20A in short bursts – before fuses start to blow. You can get past this if you have one that allows for a plug-in accessory, such as many of the Flukes do.
- AC & DC measurements up to 600A
- True RMS with low pass filter
- Also measures voltage, resistance, continuity, capacitance, frequency
- AC amperage to 400A
- True RMS responsiveness
- Also measures AC & DC voltage, resistance
- One of Fluke’s cheaper models
They consist of a dial and display and are either auto- or manual-ranging. As with clamp meters, most are digital nowadays, but are typically available in many more brands.
- Good range of features for a cheap multimeter
- Includes capacitance
- A bit slow
- Good build quality from a decent make
- Includes temperature input and a micro-amps range
- Also good for HVAC engineers
- Voltage detection
Basic clamp meter: Measures higher AC amperage only and is without other measure criteria.
Advanced: Also has other functions, or perhaps loop/inrush current features. Some also boast wireless connectivity or have a detachable display.
Basic multimeter: Can measure voltage, resistance, continuity to varying degrees of accuracy.
Advanced: More features & functionality (such as Min/Max recording), better reliability, higher accuracy and resolution, faster continuity checks / auto ranging, and safer (higher CAT ratings).
- Lets you measure current without breaking the circuit
- Ideal for troubleshooting current in-situ
- Good for dual-purpose measuring, such as a machine speed as well as current drawn
- Generally lower accuracy and resolution
- Might struggle to open jaws in tightly-packed trunking
- More measurement criteria, such as voltage, capacitance and frequency
- Measure electrical systems to a higher resolution
- Better for electronics work
- Blows fuses on higher amps
There used to be stark clamp meter vs multimeter differences, with a clamp primarily built to measure amperage and a multimeter for voltage, resistance and establishing continuity, with less focus on current. Today, the line is blurred and a good model can be an electrician’s bosom buddy. Those requiring more accuracy would be better with a separate, high quality multimeter together with an amp clamp for heavier work.