FLUKE i400 AC Current Clamp, 400A, 1mV/A Output, CAT III 600V 2277225

Electricians and maintenance technicians working in industrial plants or commercial buildings often need to measure AC current without interrupting the circuit. The FLUKE i400 AC Current Clamp makes this possible by clamping around a conductor and converting the current into a millivolt signal that any standard multimeter can read. With a measurement range up to 400A AC and a 32mm jaw opening, it handles most common conductors found in distribution panels and motor circuits.

Key specifications

• AC current range: 1A to 400A AC RMS
• Output signal: 1mV per amp AC (e.g., 400mV at 400A)
• Basic accuracy: ±2% ±5 digits (45–65Hz)
• Frequency response: 5Hz to 20kHz
• Jaw opening: 32mm (1.25in) for conductors up to 32mm diameter
• Safety rating: CAT III 600V, CAT IV 300V
• Output connector: shrouded 4mm banana plugs
• Cable length: 1.5m
• Passive operation – no batteries required

Why choose it

The i400 is a reliable and accurate current transformer that works with most digital multimeters featuring 4mm banana inputs and 1MΩ input impedance. Its passive design means it draws power from the meter, so you never have to worry about dead batteries. The rugged construction and safety ratings make it suitable for use in CAT III and CAT IV environments, giving you confidence when working on live circuits.

Ideal use cases

• Measuring motor current in industrial control panels
• Verifying load balance in three-phase systems
• Troubleshooting HVAC equipment and compressors
• Monitoring current in building wiring without disconnecting
• Recording current trends with a logging multimeter

Good to know

The clamp outputs 1mV per amp, so set your multimeter to the AC millivolt range and read directly in amps. The 1.5m cable gives you flexibility to position the meter safely while the clamp is attached. The i400 is compatible with a wide range of Fluke multimeters as well as other brands that accept standard banana plugs.