In the Russian system describes the reliability of the electricity service in a building based upon how the building receives its electricity from the electrical infrastructure of the city or district. Category 1 is for very important buildings where the even the short term cut off of electricity would have serious consequences: potential loss of life, damage to important infrastructure, communications, etc. Category 1 buildings must be connected to two independent sources of electricity each of which provides the full Permitted Capacity for the building. The permitted cut off time is only the time required for the automatic switch over from one source of electricity to the other. Within Category 1 Special Group buildings must have Uninterrupted Power Supply to avoid damage, fire or other emergency situations. Category 2 buildings are those where a loss of electrical power would result in a reduction of production, risk of work stoppage or interruption of the activities of a large number of people. Power to Category 2 buildings must be provided by two independent sources and be restoreable by the operations team of the consumer or mobile brigade of the electricity provider. For Category 3 buildings, the normative time for the restoration of power is 24 hours.