This European Standard specifies the characteristics as well as the verification of bonding in on-board aircraft electrical systems. They refer basically to requirements relating to the effect of lightning, return currents, electromagnetic interference, as well as to the accumulation of electrostatic charges and personnel shock hazard. This standard states the maximum permissible resistance values which guarantee, according to the installation, good conductivity of the whole of the structure, of the whole installation and the bonding terminals; these values shall ensure correct operation of the systems. The rules of installation are defined in EN 3197.