4-wire, delta-connected systems shall be permitted to have the same phase configuration as the metering equipment.
FPN: See 110.15 for requirements on marking the busbar or phase conductor having the higher voltage to ground where supplied from a 4-wire, delta-connected system.
(F) High-Leg Identification. A switchboard or panelboard containing a 4-wire, delta-connected system where the mid point of one phase winding is grounded shall be legibly and permanently field marked as follows:
"CautionPhase HasVolts to
Ground"
(G) Minimum Wire-Bending Space. The minimum wire bending space at terminals and minimum gutter space provided in panelboards and switchboards shall be as required
in 312.6.
408.4 Circuit Directory or Circuit Identification. 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 overcurrent 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 panelboard, and located at each switch on a switchboard. No circuit shall be described in a manner that depends on transient conditions of occupancy.
(B) 408.5 Clearance for Conductor Entering Bus Enclosures. Where conduits or other raceways enter a switchboard, floor-standing panelboard, or similar enclosure at the bottom, sufficient space shall be provided to permit installation of conductors in the enclosure. The wiring space shall not be less than shown in Table 408.5 where the conduit or raceways enter or leave the enclosure below the busbars, their supports, or other obstructions. The conduit or raceways, including their end fittings, shall not rise more than 75 mm (3 in.) above the bottom of the enclosure.
Table 408.5 Clearance for Conductors Entering
Bus Enclosures
Minimum Spacing Between Bottom of Enclosure and Busbars, Their Supports, or Other Obstructions
Conductor mm in.
Insulated busbars, their 200 8 supports, or other
obstructions
Noninsulated busbars 250 10
408.7 Unused Openings. Unused openings for circuit breakers and switches shall be closed using identified closures, or other approved means that provide protection substantially equivalent to the wall of the enclosure.
II. Switchboards
408.16 Switchboards in Damp or Wet
Locations.
Switchboards in damp or wet locations shall be installed in accordance with 312.2.
408.17 Location Relative to Easily Ignitible
Material.
Switchboards shall be placed so as to reduce to a minimum the probability of communicating fire to adjacent combustible materials. Where installed over a combustible floor, suitable protection thereto shall be provided.
408.18 Clearances.
(A) From Ceiling. For other than a totally enclosed switchboard, a space not less than
900 mm (3 ft) shall be provided between the top of the switchboard and any combustible ceiling, unless a noncombustible shield is provided between the switchboard and the ceiling.
(B) Around Switchboards. Clearances around switchboards shall comply with the provisions of 110.26.