Modifications reserved Page 9/79OPM_SGS_USM_M40_M50_2US_V010.doc User Manual SG Series 400 & 500 UL S2Safety symbols and warningsSafety warningsThe text of this manual contains some warnings to avoid risk to the persons and to avoid damages tothe UPS system and the supplied critical loads.The non-observance of the warnings reminding hazardous situations could result in human injury andequipment damages.Please pay attention to the meaning of the following warnings and symbols.Throughout this manual the following symbols are defined:WARNING, if instruction is not followed injury or serious equipment damage mayoccur!CAUTION, internal parts have dangerous voltage present.Risk of electric shock!PE (Earth) – GND (Ground)PROTECTIVE GROUNDING TERMINAL:A terminal which must be connected to earth ground prior to making any otherconnection to the equipment.A terminal to which or from which an alternating (sine wave) current or voltagemay be applied or supplied.A terminal to which or from which a direct current or voltage may be applied orsupplied.This symbol indicated the word “phase”.This symbol indicates the principal on/off switch in the on position.This symbol indicates the principal on/off switch in the off position.