UL-67-2009 pdf download – Panelboards.
4.7 BONDING JUMPER – A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected. 4.8 BONDING SCREW – A screw that is used as a bonding jumper. 4.9 BUS – A conductor, or group of conductors, that serves as a common connection for two or more circuits. 4.10 CABINET – An enclosure designed for either surface mounting or ush mounting and is provided with a frame, mat, or trim in which a swinging door or doors are or can be hung. 4.11 CARTRIDGE FUSE – A fuse consisting of a current-responsive element inside a fuse body with contacts on both ends. 4.12 CIRCUIT BREAKER – A device designed to open and close a circuit by nonautomatic means, and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating. 4.13 CLASS CTL PANELBOARD – A panelboard that has physical means to prevent the installation of more than 42 overcurrent devices, or if fewer than 42, that number for which the panelboard was designed and rated. Note 1 – When properly installed, Class CTL panelboards will comply with the Lighting and Appliance Branch-Circuit Panelboard requirements in the National Electrical Code. Note 2 – Class CTL panelboards were included in 1965 through 2005 editions of the National Electrical Code. Requirements within this Standard dealing with Class CTL Panelboards are applicable to products for use with those Codes. 4.14 CONTINUOUS DUTY – Operation at a substantially constant load for an indenitely long time. 4.15 CURRENT-LIMITING DEVICE (AC) – An overcurrent protective device that, when interrupting currents in its current-limiting range, will reduce the current owing in the faulted circuit to a magnitude substantially less than that obtainable in the same circuit if the device were replaced with a solid conductor having a comparable impedance.
4.16 CURRENT RATING – The designated maximum direct current or alternating current (RMS Amperes at rated frequency) that a device can carry continuously under specied conditions. 4.17 CUTOUT BOX – An enclosure designed for surface mounting that has swinging doors or covers secured directly to and telescoping with the walls of the box proper. 4.18 DEADFRONT – A barrier that prevents live parts from being exposed to a person on the operating side of the panelboard. 4.19 DEADFRONT SHIELD – A barrier that is used behind a door to cover wiring spaces and uninsulated live parts that would otherwise be exposed to a person when the door is open. 4.20 DEVICE – A unit of an electrical system that is intended to carry or control, but not utilize, electrical energy.