Clamp meters have their place in the amperage test world, being more useful than a standard multimeter in the case of high current values and accessibility. With a Fluke amp clamp, you don’t need to power down machinery before testing as they are non-contact and measure inductance in a given circuit.
Amp clamps have come a long way from the early days of dedicated amperage-only testing, typically including traditional multimeter ranges today, such as voltage and resistance. There are even wireless and detachable display varieties for ultimate safety.
Amprobe originally came up with the concept and they make solid equipment. As with their multimeters, Fluke seems to have gone the extra mile to produce a great range of clamps. These include standard amp-only models, to rugged, industrial clamp-multimeters, HVAC clamps, and wide-jaw varieties suited to heavy industry.
Many of these also have data logging capability and are fitted with Fluke Connect® to wirelessly talk with other devices, PCs and smartphones, such that you can share data.
A selection of Fluke amp clamp meters and multimeters:
This is one of their entry level amp clamp meters. It has basic functionality, able to measure to 400A AC and also includes voltage, resistance and continuity check ranges. Despite being one of their cheaper devices, it is also True RMS for accurate AC results on waveforms other than standard sinusoidal.
Good for general AC work, the 323 is okay for both residential and some commercial work. It is one of the slimmer amp clamps and is rated 300V CAT-IV. The main downsides are the lack of DC amperage scale and an unlit display. See full review…
Fluke 368 FC
More professional, and expensive, is this current leakage clamp meter. As such, it measures lower amperages – between 3mA and 60A – and is used for detecting AC issues. It comes with wireless connectivity, good resolution and wide jaws (to 40mm Ø).
The 368 is also a data logger and boasts Min/Max recording, a noise filter, backlit display, LED flashlight and FC connectivity. Rated to CAT-III 600V, it is best for maintenance engineers and electricians. See full review…
The 370 series of amp clamps from Fluke includes the high-performance 375 FC, which also has wireless connectivity and data logging options. It is a big step up from the 320 series of meters in that it can measure both AC and DC amps (to 600A) and also has the option to go to 2500A with the addition of an iFlex current probe.
This is a True-RMS device, meaning accurate direct measurements of voltage and amperage for non-sine waves. You can also measure voltage to 1000V AC/DC (and down to DC millivolts), along with resistance to 60kΩ, continuity, capacitance to 1000μF, and frequency. It also has Min/Max/Average recording mode and the Fluke Connect button lets it talk to smartphones and computers.
376 FC Wireless
The 376 is the same device as the 375, though it can measure DC current to 1000A, as opposed to only 600A, and comes included with the iFlex current probe. This handy probe also allows for the measurement of large sized conductors. Both units also have a backlit screen and are CAT-IV rated at 600V.
381 Remote Display
The 381 is a clamp meter with a remote, detachable display that also comes with an iFlex current probe for higher amperage measurements. It is True-RMS that can measure both AC and DC current and features standard multimeter test ranges. These include voltage, resistance and continuity.
The beauty of the 381, of course, is that you can remove yourself from cabling/machinery and read the measurement values from afar. Other pluses include a backlit display, noise filter and carry case. CAT-IV rated.
As with standard amp clamps, the 902 can measure high current values, albeit to AC amperage only. Being HVAC compliant, however, it also has a temperature range and a micro-amp range – good for checking out flame sensors and so forth. You also have voltage, resistance, continuity and diode check ranges and it can wirelessly send data up to 30m. Category ratings: CAT-IV to 300V, CAT-III to 600V.
A3003 FC Wireless
This is a dedicated current clamp meter for DC supplies. Noted for its wide jaw, to enable measurement of large conductors (max: 64mm), it can measure DC amperage from 10A to a whopping 2000A. It is thus suited to heavy manufacturing industry, such as marine or mining.
It also has a logging function and wirelessly connects to other devices, such as the Fluke 3000 multimeter and the Ti300 infrared camera.
If you need to measure big amps, current in large conductors or any conductor away from source, and to do this covertly, an amp clamp is the way to go. Fluke amp clamp meters are the best around, with a typically slick, rugged finish and lots of features. Though expensive, they offer great accuracy and reliability and are gimmick-free