Note• As indicated above, do not tighten the screw fully.• The pull-out strength of the installation area must be at least 294 N (30 kgf) per screw.• Do not block the operations of the cabinet. Allow space of at least 20 cm (8 in) above, 10 cm (4 in)at the sides, and 10 cm (4 in) below the PBX.• Make sure that screw heads are the same distance from the wall.• Install the screw perpendicular to the wall.• Be careful not to drop the cabinet.4. Hook the main unit on the screw heads.3.2.9 Surge Protector InstallationCAUTIONPerforming surge protection is essential. Make sure to follow the instructions in this section.OverviewA massive electrical surge can be caused if lightning strikes a telephone cable 10 m (33 ft) above ground, orif a telephone line comes into contact with a power line. A surge protector is a device that is connected to atrunk to prevent potentially dangerous electrical surges from entering the building via the trunk anddamaging the PBX and connected equipment.To protect the system from electrical surges, we strongly recommend connecting the system to a surgeprotector that meets the following specifications:– Surge arrestor type: 3-electrode arrestor– DC spark-over voltage: 230 V– Maximum peak current: at least 10 kAAdditionally, proper grounding is very important for the protection of the system (refer to "3.2.4 FrameGround Connection").Many countries/areas have regulations requiring surge protection. Be sure to comply with all applicablelaws, regulations, and guidelines.3.2.9 Surge Protector InstallationGetting Started 55