General
Readability	180° Winkel

The earth resistance clamp C.A 6418 from Chauvin Arnoux is a specialised measuring instrument for testing earth loop resistances in electrical installations. It is particularly designed for use on strip earths, where the elongated measuring head enables secure encirclement of rectangular current busbars (30 x 40 mm, 20 x 55 mm) as well as cables with a diameter up to 32 mm. The device is used to check the earthing characteristics in industrial and commercial electrical installations, ensuring the safety and reliability of the installation.

Applications

The clamp is used in electrical practice to measure the resistance of earth loops, which serve as a protective measure in case of faults in the electrical system. It is suitable for testing equipment that features strip earths or cable earthing, particularly in production plants, machine building, building technology, and during maintenance work on electrical installations. The measurement is contactless, thereby minimising the risk of short circuits or electrical contact.

Functions and equipment in detail

The C.A 6418 simultaneously displays the earth loop resistance in ohms (Ω) and the leakage current in amperes (A). This simultaneous display enables a comprehensive evaluation of earthing characteristics. The OLED display ensures excellent readability under all lighting conditions, including strong sunlight, and is readable from an angle of 180°. The automatic Pre-HOLD function when the clamp is open simplifies measurement preparation, while the automatic air gap calibration upon switching on ensures constant measurement accuracy.

Technology explained simply

The device measures the resistance of the earth loop by passing a test current through the loop and measuring the voltage drop. The resistance is calculated from the ratio of voltage to current. The resistance measurement range extends from 0.010 Ω to 1,200 Ω, enabling the capture of both very low and very high values. Current measurement is performed in the range of 0.5 mA to 20 A, which is sufficient for most applications. The integrated memory function allows recording of up to 300 measurement values, each stamped with time and date, which is important for documentation and traceability.

Compatibility and accessories

The clamp is specifically designed for strip earth cross-sections and can encircle cables up to 32 mm in diameter. Optionally, a calibration loop CL1 is available, enabling on-site clamp calibration without having to return the device to the manufacturer. This increases efficiency during on-site maintenance and testing.

Installation and mounting

Installation is carried out by simply encircling the conductor or busbar to be tested with the clamp. No additional mounting or wiring is required. The clamp is placed directly onto the object to be tested, and the measurement starts automatically after closing the clamp. Operation is performed via buttons on the top of the device, designed for navigating menus and selecting functions.

Advantages in operation

The simultaneous display of resistance and current enables quick assessment of earthing characteristics. The memory function with time and date stamp supports documentation of tests. The OLED display ensures good readability even outdoors. Automatic functions such as Pre-HOLD and air gap calibration reduce operator effort and increase the reliability of measurement results. The device is delivered in a robust transport case, providing protection against mechanical damage. The operating manual is included in the delivery scope.

Delivery contents

The delivery includes the earth resistance clamp C.A 6418, a robust transport case, and the operating manual. Optionally, the calibration loop CL1 is available, which can be used for on-site clamp calibration. Batteries are not included in the delivery scope.