1.1 These requirements cover assemblies of wiring terminals and supporting blocks intended to provide for the connection of wiring. Compliance with these requirements does not assure that the terminal block is suitable for use as a component of an end product.
1.2 These requirements cover terminal blocks rated 1500 volts or less.
1.3 These requirements also cover protective conductor terminal blocks (PCTB) used to make the electrical and mechanical connection between conductors or between conductors and a fixing support such as a mounting rail. A PCTB is not required to be insulated.
1.4 These terminal blocks are intended to permanently support and insulate wire terminations and joints from each other, and from the surface on which the terminal block is mounted, where the absence of such support or insulation presents a risk of fire, electric shock, or injury to persons.
1.5 The acceptability of a terminal block in any particular application depends upon its suitability for continued use under the conditions that prevail in actual service. Accordingly, for a particular application a terminal block may be affected by the requirements for the equipment in which it is used, and it may be necessary to additionally evaluate that terminal block for features or performance characteristics that are not specified in this standard.
1.6 Terminal blocks employing types of connecting means not covered by this standard such as those in which conductors are secured to the terminals by means of a special tool can be evaluated under this standard but may require separate investigation.
1.7 These requirements do not cover field installed power distribution blocks intended to distribute power in a building to separate units such as apartments, separate heaters, and air conditioning units. Power distribution blocks are investigated to Subject 1953, Outline of Investigation for Power Distribution Blocks.