under load, and disconnecting link enclosures shall be interlocked to prevent access to energized parts.

368.240

Wiring 600 Volts or Less, Nominal. Secondary control devices and wiring that are provided as part of the metal-enclosed bus run shall be insulated by fire-

retardant barriers from all primary circuit elements with the exception of short lengths of wire, such as at instrument transformer terminals.

368.244 Expansion Fittings. Flexible or expansion con- nections shall be provided in long, straight runs of bus to allow for temperature expansion or contraction, or where the busway run crosses building vibration insulation joints.

368.258 Neutral Conductor. Neutral bus, where required, shall be sized to carry all neutral load current, including harmonic currents, and shall have adequate momentary and short-circuit rating consistent with system requirements.

368.260 Grounding. Metal-enclosed busway shall be grounded.

368.320 Marking. Each busway run shall be provided with a permanent nameplate on which the following information shall be provided:

(1) Rated voltage.

(2) Rated continuous current; if bus is forced-cooled, both the normal forced-cooled rating and the self- cooled (not forced-cooled) rating for the same temperature rise shall be given.

(3) Rated frequency.

(4) Rated impulse withstand voltage.

(5) Rated 60-Hz withstand voltage (dry).

(6) Rated momentary current.

(7) Manufacturer's name or trademark.

FPN: See ANSI C37.23-1987 (R1991), Guide for Metal- Enclosed Bus and Calculating Losses in Isolated-Pliase Bus, for construction and testing requirements for metal-enclosed buses.