11. Introduction1.1 Safety instruction The UPS must be installed and maintained exclusively by quailifiedstaff. See installation and operation instructions before connecting tothe supply. The UPS must be installed with an earth connection. It has a highleakage current. The first wire to be connected is the earth wire, whichmust be connected to the terminal marked PE (yellow/green). The UPS generates a leakage current of over 3.5 mA. The leakagecurrent of the load should be added to that of the UPS on theprotective earth wire. The UPS needs a neutral connection to work properly. Operationwithout Neutral may damage the unit. A readily accessible disconnect device shall be incorporated in thebuilding installation wiring for permanently connected equipment. The UPS generates hazardous electric voltages inside it even whenthe input and/or battery switches are open. The inside of the UPS isprotected by safety guards that are not to be removed by non-qualifiedstaff. All installation and maintenance or other operations that entailgaining access to the inside of the UPS require the use of tools andare to be performed exclusively by qualified staff. The UPS contains an energy source: the batteries. All terminals andsockets may be powered even when the UPS is not connected to themains. The total battery voltage is potentially hazardous: it may cause anelectric shock. The compartment containing the batteries is protectedby safety guards, which are not to be removed by non-qualified staff.