210.6 Branch-Circuit Voltage Limitations. The nominal
voltage of branch circuits shall not exceed the values permitted
by 210.6(A) through (E).
(D) 600 Volts Between Conductors. Circuits exceeding
277 volts, nominal, to ground and not exceeding 600 volts,
nominal, between conductors shall be permitted to supply
the following:
(1) The auxiliary equipment of electric-discharge lamps
mounted in permanently installed luminaires where
the luminaires are mounted in accordance with one
of the following:
a. Not less than a height of 6.7 m (22 ft) on poles or
similar structures for the illumination of outdoor areas
such as highways, roads, bridges, athletic fields,
or parking lots
b. Not less than a height of 5.5 m (18 ft) on other
structures such as tunnels
(2) Cord-and-plug-connected or permanently connected
utilization equipment other than luminaires
(3) Luminaires powered from direct-current systems where
the luminaire contains a listed, dc-rated ballast that provides
isolation between the dc power source and the
lamp circuit and protection from electric shock when
changing lamps.
Informational Note: See 410.138 for auxiliary equipment
limitations.
