Matis-Nomad is a secure grounding clamp which allows, in explosive atmospheres, to insure a correct ground connection of the containers avoiding electrostatic charges during filling and discharging operations. The ATEX design of the Matis-Nomad permits to control a potential spark when grounding the containers. The clamp is fitted with a spiral cable wired to the movable enclosure which plugs on a wall support. The device is suitable for any container type, and is movable and stand-alone. A version with digital outputs is available.