UL-2577:2013 pdf free download – STANDARD FOR SAFETY Suspended Ceiling Grid Low Voltage Systems and Equipment.
13.3 A bus bar insulator shall be secured to the grid rail by mechanical fit or adhesives. The insulator shall continue to preform its intended function after being subjected to the performance tests specified within this standard.
14 Current-Carrying Parts
14.1 The current-carrying part of a system shall be of copper, a copper alloy, aluminum, or other material investigated and found to meet the performance requirements of this standard.
14.2 A current-carrying part shall have mechanical strength and ampacity for the intended use and shall be of metal or other material that is acceptable for the application.
14.3 Current-carrying parts shall be isolated from dead metal parts.
14.4 Conductors shall be 18 AWG (0.82 mm2) minimum copper or equivalent cross sectional area.
Exception: Conductors of a size smaller than 18 AWG copper (0.82 mm2) or equivalent, but not smaller than 24 A WG copper or equivalent, may be used for Class 2 circuits where they are completely enclosed and not subject to movement or strain under normal use or installation.
14.5 The power feed conductors shall be 16 AWG copper (1.3 mm2) minimum or equivalent cross sectional area.
14.6 The bus bars shall be 16 AWG copper (1.3 mm2) minimum or have an equivalent cross sectional area. For a bus bar with a circular cross section the diameter should be 1.29 mm (0.051 in) copper minimum or equivalent, and for a cross section other than circular the area should be 1 .32 mm2 (0.002 in2) copper or equivalent.
14.7 A bus bar and connectors which have current carrying parts which are exposed or can be repositioned during use, shall be plated with silver, tin, nickel, or similar corrosion resistant material to withstand the long term effects of indoor atmospheric corrosion.
14.8 Iron or steel, if protected against corrosion, may be used for screws, plates, yokes, springs, or other parts that are employed as a means of clamping the conductor, if such parts are not the primary current-carrying members.
15 Securement of Components
15.1 An uninsulated live part, including a terminal, shall be secured to its supporting surface by a method other than friction between surfaces so that it will be prevented from turning or shifting in position if such motion may result in reduction of spacings below the minimum acceptable values. The security of a contact assembly shall maintain continued alignment of contacts.
15.2 The means for preventing the turning or shifting mentioned in 15.1 is to consist of more than friction between surfaces — for example, a properly applied lock washer is acceptable as the means for preventing a small stem-mounted switch or other device having a single-hole mounting means from turning.
15.3 A live screw head or nut on the underside of an insulating base shall be prevented from loosening
and shall be acceptably insulated or spaced from the mounting surface.
16 Splices and Connections
16.1 A splice shall be provided with insulation and mechanical protection equivalent to that of the conductors involved.
16.2 In determining if splice insulation consisting of fabric, thermoplastic, or other type of tubing is acceptable, consideration is to be given to such factors as its dielectric properties, heat- and moisture-resistant characteristics. Thermoplastic tape wrapped over a sharp edge is not acceptable.
16.3 A soldered connection shall be made mechanically secure before being soldered.
16.4 A lead is considered to be mechanically secure when one or more of the following is provided prior to soldering.