The Hioki CM3289 True-RMS AC Clamp Meter is a True-RMS rectifying 1000A AC clamp meter that has been designed with a thin sensor to help you get into the tightest spaces. The compact profile allows you to quickly clamp wires in confined spaces, yielding outstanding ease of use. The CM3289 utilizes True-RMS measurement, which produces accurate display values even when measuring a distorted waveform, for example from an inverter-equipped device or switching power supply. When connected to an optional flexible current sensor (sold separately), 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.

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 provides voltage measurement, continuity check, and resistance measurement functionality. Despite its thin, compact design, the CM3289 has a broad operating temperature range of -13°F to 149°F (-25 °C to 65 °C) and can withstand being dropped from a height of 1 meter onto concrete. It is engineered for use in tough environments.