These requirements cover power distribution blocks that are rated 1000 volts or less and intended to be used on either the line side or load side of service equipment in accordance with the National Electrical Code@ NFPA 70. These requirements also cover power distribution blocks that are rated 1500 volts DC or less and intended to be used in photovoltaic applications in accordance with Article 690 of the National Electrical Code@ NFPA 70. These blocks are used for splicing and tapping conductors in order to distribute power to separate circuits or loads. A power-distribution block consists of one or more connectors mounted on an insulating base. Each connector has provision for one or more incoming conductors and multiple tap-off conductors. A tap-off conductor is of the same or smaller size as the incoming conductor. The connectors may be of the lay-in construction which do not require the incoming conductor to be terminated. A power distribution block is intended to permanently support and insulate the wire terminations and joints of each polarity from each other@ and from the surface on which the power distribution block is mounted. A power distribution block may also be provided with an insulating cover. These requirements do not cover terminal blocks which are covered by the Standard for Terminal Blocks@ UL 1059.