UL 67-2020 pdf download – Panelboards.
3 Units of Measurement 3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information. 4 Undated References 4.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard. 5 Glossary 5.1 For the purpose of this standard, the following definitions apply. 5.2 AMBIENT TEMPERATURE – The temperature of the surrounding medium that comes in contact with the panelboard. For an enclosed panelboard, it is the temperature of the medium outside the enclosure. 5.3 AMPACITY – The current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating. 5.4 AVAIL ABLE SHORT-CIRCUIT CURRENT – That current which would flow in a circuit if a short-circuit of negligible impedance were to occur at a given point. 5.5 BARRIER – A partition for the insulation or isolation of electric circuits or electric arcs. 5.6 BONDING – The permanent joining of metallic parts to form an electrical conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed. 5.7 BONDING JUMPER – A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected. 5.8 BONDING SCREW – A screw that is used as a bonding jumper. 5.9 BUS – A conductor, or group of conductors, that serves as a common connection for two or more circuits.
5.47 MAINS (MAIN TERMINALS) – The terminals, or main device, provided for the connection of the main incoming line conductors. 5.48 NEUTRAL (ASSEMBLY); SOLID NEUTRAL – An assembly consisting of enough terminals to provide for the connection of the grounded (neutral) line and load conductors. When used as a component of service equipment, the neutral also includes the following: a) A means for making the required bonding connection between the neutral and the enclosure; and b) A terminal for the grounding electrode conductor. 5.49 NEUTRAL CONDUCTOR – A conductor that is connected to the midpoint of a three-wire single- phase system, the center point of a wye-connected three-phase system, or the midpoint of one side of a delta-connected three-phase system. Note: The neutral conductor is the grounded conductor. 5.50 OVERCURRENT PROTECTIVE DEVICE – An individual fuse or circuit breaker pole. 5.51 PANELBOARD – A single panel or a group of panel units designed for assembly in the form of a single panel; includes buses, automatic overcurrent devices, and may be equipped with switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall or partition and accessible only from the front. 5.52 PEAK LET-THROUGH CURRENT (AC) – The maximum instantaneous current through an overcurrent device during the total clearing time. 5.53 PLUG FUSE – A screw-in type fuse for use in an Edison base type fuseholder.