Digital multimeter Benning CM E1 — handheld meter, battery powered, dimensions 276×100×47 mm, CAT III 300V

Benning CM E1 is a handheld digital multimeter designed for electrical measurements in environments up to CAT III 300V. Battery powered and compact (276×100×47 mm), this meter combines clamp-based earth loop resistance measurement with TRUE RMS current measurement for leakage and load currents from 0.3 mA to 35 A. The instrument uses an excitation winding and a sensor winding in the measuring clamp to induce and detect current in the clamped earthing conductor, allowing calculation of the entire earth loop resistance without disconnecting the earthing conductor.

Advantages

The clamp-based earth loop resistance measurement eliminates the need for auxiliary earth electrodes or disconnection of the earthing conductor, enabling safe, fast and non-invasive testing even in corroded or hard-to-access earthing points. TRUE RMS measurement ensures accurate readings for both sinusoidal and non-sinusoidal currents. The meter’s handheld form factor and battery operation make it suitable for on-site inspections, service work and troubleshooting in installations where CAT III 300V protection is required.

Suitable for

• Measuring earth loop resistance in multiply earthed systems without disconnecting the earthing conductor
• Measuring leakage and load currents from 0.3 mA to 35 A using TRUE RMS
• Testing and troubleshooting electrical installations, street lighting and telecom groundings
• Inspection of lightning protection systems and overhead line networks with pole-type earth electrodes
• Routine maintenance and service work where portable, battery-powered meters are required

Key specifications

• Protection category: CAT III 300V
• Dimensions: 276 × 100 × 47 mm
• Power supply: battery operated
• Earth loop resistance measurement via clamp (no disconnection or auxiliary probes needed)
• Leakage and load current measurement range: 0.3 mA to 35 A (TRUE RMS)
• Measuring principle: excitation winding and sensor winding in clamp; induced AC excitation at approx. 3.333 kHz

How to use

Place the measuring clamp around the earthing conductor to be tested, ensuring the conductor is centered in the clamp jaws. Activate the meter and select the earth loop resistance function or current measurement as required. For earth loop resistance, the meter applies a constant AC excitation to induce current; the sensor winding measures the induced current and the instrument calculates the resistance as the ratio of excitation voltage to measured current. For current measurements, enclose the conductor with the clamp and read the TRUE RMS value displayed. Follow general safety procedures for working on live installations and observe the CAT III 300V rating.

Usage recommendations

To obtain reliable earth loop resistance readings, ensure the clamp fully encloses a single conductor and avoid nearby parallel conductors in the clamp opening. Use the TRUE RMS mode for non-sinusoidal currents and perform measurements with stable connections; keep batteries charged and verify zero or offset functions where available before critical tests.