1.1 These requirements cover power distribution blocks that are rated 600 volts or less and intended to
be used on the load side of service equipment in accordance with the National Electrical Code, NFPA 70.
These blocks are used for splicing and tapping conductors in metallic wireways, auxiliary gutters, junction
boxes, termination boxes, and the like, in order to distribute power to separate circuits or loads.
1.2 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.
1.3 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.
1.4 These requirements do not cover terminal blocks which are covered by the Standard for Terminal
Blocks, UL 1059.
1.5 A product that contains features, characteristics, components, materials, or systems new or different
from those covered by the requirements in this Outline of Investigation, and that involves a risk of fire,
electric shock, or injury to persons shall be evaluated using the appropriate additional component and
end-product requirements as determined necessary to maintain the acceptable level of safety as originally
anticipated by the intent of this Outline of Investigation. A product whose features, characteristics,
components, materials, or systems conflict with specific requirements or provisions of this Outline of
Investigation cannot be judged to comply with this Outline of Investigation.