Proper Circuit Identification is not only required by NEC and OSHA but will also pay for itself a thousand times over by eliminating countless hours spent searching for circuits that are not identified and labeled. ESS can get your panel schedules and equipment labeling back in shape. Not only is this a requirement for the safety of your personnel but proper labeling will save your company thousands of hours allowing you to know the power sources for your equipment. Hours will be saved by not having your maintenance personnel waste time searching for unknown power sources and avoid potentially fatal lockout locations.
OSHA definitions for proper Circuit Identification
408.4 Field Identification Required
(A) Every circuit and circuit modification shall be legibly identified as to its clear, evident and specific purpose or use. The identification shall include sufficient detail to allow each circuit to be distinguished from all others. Spare positions that contain unused over-current devices or switches shall be described accordingly. The identification shall be included in a circuit directory that is located on the face or inside of the panel door in the case of a panel-board and located at each switch or circuit breaker in a switchboard. No circuit shall be described in a manner that depends on transient conditions of occupancy.
(B) Source of supply. All switchboards and panel-boards supplied by a feeder in other than one or two family dwellings shall be marked to indicate the device or equipment the power originates.
110.22 Identification of Disconnecting Means
(A) General. Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident. The marking shall be of sufficient durability to withstand the environment involved.
700.10 Wiring, Emergency System
(A) Identification. All boxes and enclosures (including transfer switches, generators and power panels) for emergency circuits shall be permanently marked so they will be readily identified as a component of an emergency circuit system.
708.10 Feeder and Branch Circuit Wiring
(1) Boxes and Enclosures. All boxes and enclosures (including transfer switches, generators, and power panels) for critical operations power system (COPS) shall be permanently marked so they will be readily identified as a component of the system.
Service Equipment – Disconnecting Means
230.70(B) Marking. Each service disconnect shall be permanently marked to identify it as a service disconnect.
409.102(B) Phase Arrangement. The phase arrangement of a 3 phase horizontal common power and vertical buses shall be A,B, C from front to back, top to bottom or left to right, as viewed from the front of the industrial control panel. The B phase shall be that phase having the higher voltage to ground on 3- phase, 4-wire, delta connected systems. Other busbar arrangements shall be permitted for additions to existing installations, and the phases shall be permanently marked.