Surge Protective Devices. Description. Installation

The first article Low voltage surge arresters. Components. Réseaux basse tension [D4840] presented recent technical and normative developments in the field of surge protection. Knowledge of these elements is essential to a good understanding of the selection mechanisms and installation rules for surge arresters, which are presented in this second article. Indeed, today's surge arresters have taken advantage of these developments, and their characteristics have improved the effectiveness of surge protection. Surge arresters perform two main functions: equipotential bonding between the electrical installation and the building's earth, and protection of sensitive equipment. The equipotentiality surge arrester is installed at the head of the installation in the building, and is designed to prevent ignitions and fires in the structure. The other surge protectors protect equipment and are located in the structure not far from the equipment to be protected. The two functions (equipotentiality and protection) of the surge arrester are directly linked to the characteristics of the components that make up the active part. A detailed description of the components used and their advantages and disadvantages can be found at [D4840] . However, these two main functions of an arrester have evolved less than the secondary functions (arrester fault indicator, remote status feedback, end-of-life control, etc.) which are now an integral part of most low-voltage arresters. These functions have sometimes taken on greater importance than the protection itself in the choice of arrester.

In recent years, knowledge of surge voltages and low-voltage networks has accelerated. The current state of knowledge in this field is presented in [D4840] . At the same time, significant progress has been made in surge arrester technology and testing facilities. Today's arresters have little in common with the previous generation, particularly when it comes...