Quickly clamp wires in even more confined spaces!
Hioki clamp meters are best-in-class measuring devices incorporating
Hioki’ s expertise in current sensing technology. The CM3289 is a True
RMS rectifying 1000A AC clamp meter that features a broad operating
temperature range of -25° C to 65° C, thin and compact clamp core and
optional flexible current sensor that you can attach to let you get into
the tightest spots.

Model No. (Order Code)

CM3289True RMS

CAT IV 300 V (Current)
CAT III 600 V (Current)
CAT III 300 V (Voltage)
CAT II 600 V (Voltage)
Key Features

• The CM3289 is the successor to the popular 3280-20F with a redesigned thinner sensor to help you get into the tightest spaces.
• New redesigned sensor for even easier clamping (CM3289)
• Expanded -25 °C to 65 °C operating temperature range
• Model CM3289: Measure even harmonic waveform components using the True RMS method
• Model 3280-10F: Measure the fundamental waveform component using the average rectified method
• Connect the CT6280 flexible sensor to measure up to 4199 A in thick or paired wires

Video introducing the AC Clamp Meter CM3289

The popular 3280-20F AC Clamp Meter has be redesigned with a thinner sensor to help you get into the tightest spaces.
Watch this video to learn more.

Quickly clamp wires in even more confined spaces!

A new sensor profile yields outstanding ease of use

True RMS model capable of accurately measuring even distorted waveforms

The waveform including harmonic components is calculated according to an RMS calculation formula and displayed.
True RMS measurement yields accurate display values even when measuring a distorted waveform, for example from an inverter-equipped device or switching power supply.

A pocket clamp meter that can use flexible sensors

When connected to an optional flexible current sensor*, the CM3289 can be used to measure the current flowing in pairs of wires or in tangled or complexly routed wires around which it was not possible to apply a clamp-on sensor in the past.


Essential for electrical work: A thin card tester that fits in the pocket with all the capabilities of a clamp meter

The CM3289 delivers all the functionality of a clamp meter and card tester in the form factor of the latter. In addition to current measurement, this single instrument delivers voltage measurement, continuity check, and resistance measurement functionality.

Rugged, portable design that’s drop-resistant

Despite its thin, compact design, the CM3289 has an operating temperature range of -25°C to 65°C and can withstand being dropped from a height of 1 m onto concrete. It’s engineered for use in tough environments.

Basic specifications (Accuracy guaranteed for 1 year, Post-adjustment accuracy guaranteed for 1 year)

AC Current range42.00 to 1000 A, 3 ranges
(40 Hz to 1 kHz, True RMS),
Basic accuracy: ±1.5 % rdg. ±5 dgt.
DC Voltage range420.0 mV to 600 V, 5 ranges, Basic accuracy: ±1.0 % rdg. ±3 dgt.
AC Voltage range4.200 V to 600 V, 4 ranges
(45 to 500 Hz, True RMS),
Basic accuracy: ±1.8 % rdg. ±7 dgt.
Crest factor2.5 or less at 2500 counts
(Linearly decreases to 1.5 or less at 4200 count)
Resistance range420.0 Ω to 42.00 MΩ, 6 ranges, Basic accuracy: ±2 % rdg. ±4 dgt.
Other functionsContinuity: Buzzer sounds at 50 Ω ±40 Ω or less, Data hold, Auto power save, Drop-proof from height of 1 meter
DisplayLCD, max. 4199 dgt., Display refresh rate: 400 ms
Power supplyCoin type lithium battery (CR2032) ×1
Continuous use 70 hours
Core jaw dia.φ 33 mm (1.30 in)
Dimensions and mass57 mm (2.24 in) W × 181 mm (7.13 in) H × 16 mm (0.63 in) D, 100 g (3.5 oz)
AccessoriesCARRYING CASE 9398 × 1, TEST LEAD L9208 × 1, Coin type lithium battery (CR2032) × 1, Instruction manual × 1

CT6280 Basic specifications (Accuracy guaranteed for 1 year, Post-adjustment accuracy guaranteed for 1 year)

Core jaw dia.φ 130 mm (5.12 in) (Cable cross-section diameter: 5 mm (0.20 in); tip cap diameter: 7 mm (0.28 in))
AC Current419.9 A/ 4199 A, 2 ranges (±3.0 % rdg. ±5 dgt.)
Cable length800 mm (31.5 in)
Catalog: AC CLAMP METER CM3289Download PDF  [2MB]English

For more information, click here