A common scheme for indoor commercial lighting is to let the lighting panel circuit breakers serve double duty as light switches. In such a scheme, each breaker is also the only disconnect for the lighting circuit it controls.
So it might seem logical that you would add sign (or outline lighting) as just another of these circuits. But you can’t. One reason why is there’s an exterior wall between the sign (or outline lighting) and the breaker panel.
You must install an externally operable disconnect [600.6] at the point where the supply circuit enters a sign enclosure (or pole) [600.6(A)(1)].
The NEC also requires this disconnect to be within sight of the sign (or outline lighting) it controls [6006.(A)(2). This requirement has a couple of ramifications:
- Choose the point of circuit entry such that the disconnect mounted there is in sight of the controlled sign (or outline lighting).
- If you’re considering using one sign (or outline lighting box) enclosure as a pull box for another sign (or outline lighting system), the line of sight rule might obligate you to skip that option.
But why this second ramification? Notice the wording “enters a sign enclosure” rather than “enters the sign enclosure). If that enclosure you’re using as a pullbox is on the east wall and your sign is on the north wall, the disconnect you’re required to install on the east enclosure is not in line of sight of the sign it’s controlling on the north wall.