Токоизмерительные клещи и клещевые мультиметры

A clamp meter encloses a live conductor and detects the magnetic field generated by the current. From this it calculates the current flow without you having to disconnect any cables. Most clamp multimeters can also measure voltage, resistance and continuity via test leads – so they often replace a classic multimeter.

The measuring principle is decisive for the application. Pure AC clamps work on the transformer principle and only measure alternating current. For direct current – such as in the car, on battery storage or in a solar string – you need a clamp with a Hall sensor that detects both AC and DC. This appears as "AC/DC" in the datasheet.

If you place the clamp around a complete appliance cable, the current in the live and neutral conductors flows in opposite directions. The magnetic fields cancel each other out and the reading stays close to zero. You must always enclose a single conductor. For household appliances there are line splitter adapters that separate the conductors between plug and socket.

Pay attention to the measuring range (typically up to 400 or 600 A), the jaw opening for thick cables and True RMS for distorted currents behind power supplies or inverters. Inrush current functions help with motors and compressors. As with any measuring device, the measurement category under IEC/EN 61010 is the most important safety feature when you measure on the building installation.

For cars and photovoltaics, a DC-capable clamp with zero adjustment makes sense, because the Hall sensor can easily drift without it.

Clamp meters are used in heating and air-conditioning technology, on motors, in vehicle diagnostics and increasingly on photovoltaic systems and batteries. DIYers use them to track down parasitic drain in the car or to check the current draw of pumps and tools. For finding power hogs at home, a plug-in energy meter is usually the simpler choice.