Exit Sign

[Corey Friedman]

HI Jerry,

Do you know of any code(s) that requires Exit signs to be on an independant circuit and have the breaker locked on with an external lock-on device like the little metal clip on piece with a set screw.

Your thoughts on this would be appreciated.

Thanks

Corey

[Jerry Peck - Codeman]

Hi Corey,

That's a nice simple question with a complicated answer.

The 2008 NEC states that emergency lighting, which includes exit signs, shall have an emergency backup power supply (which is typically the battery backup exit signs) and that the switches for emergency lighting circuits shall be arranged so that only authorized persons have control of them.

While not addressing your specific questions, I believe that does address the intent and reason behind your question.

The following is from the 2008 NEC. (bold and underlining are mine)
- ARTICLE 700 Emergency Systems
- - IV. Emergency System Circuits for Lighting and Power
- - - 700.16 Emergency Illumination.
- - - - Emergency illumination shall include all required means of egress lighting, illuminated exit signs, and all other lights specified as necessary to provide required illumination.
- - - - Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a lamp, cannot leave in total darkness any space that requires emergency illumination.
- - - - Where high-intensity discharge lighting such as high- and low-pressure sodium, mercury vapor, and metal halide is used as the sole source of normal illumination, the emergency lighting system shall be required to operate until normal illumination has been restored.
- - - - - Exception: Alternative means that ensure emergency lighting illumination level is maintained shall be permitted.
- - - 700.17 Circuits for Emergency Lighting.
- - - - Branch circuits that supply emergency lighting shall be installed to provide service from a source complying with 700.12 when the normal supply for lighting is interrupted. Such installations shall provide either of the following:
- - - - - (1) An emergency lighting supply, independent of the general lighting supply, with provisions for automatically transferring the emergency lights upon the event of failure of the general lighting system supply
- - - - - (2) Two or more separate and complete systems with independent power supply, each system providing sufficient current for emergency lighting purposes
- - - - Unless both systems are used for regular lighting purposes and are both kept lighted, means shall be provided for automatically energizing either system upon failure of the other. Either or both systems shall be permitted to be a part of the general lighting system of the protected occupancy if circuits supplying lights for emergency illumination are installed in accordance with other sections of this article.
- - V. Control — Emergency Lighting Circuits
- - - 700.20 Switch Requirements.
- - - - The switch or switches installed in emergency lighting circuits shall be arranged so that only authorized persons have control of emergency lighting.
- - - - - Exception No. 1: Where two or more single-throw switches are connected in parallel to control a single circuit, at least one of these switches shall be accessible only to authorized persons.
- - - - - Exception No. 2: Additional switches that act only to put emergency lights into operation but not disconnect them shall be permissible.
- - - - Switches connected in series or 3- and 4-way switches shall not be used.
- - - 700.21 Switch Location.
- - - - All manual switches for controlling emergency circuits shall be in locations convenient to authorized persons responsible for their actuation. In facilities covered by Articles 518 and 520, a switch for controlling emergency lighting systems shall be located in the lobby or at a place conveniently accessible thereto.
In no case shall a control switch for emergency lighting be placed in a motion-picture projection booth or on a stage or platform.
- - - - - Exception: Where multiple switches are provided, one such switch shall be permitted in such locations where arranged so that it can only energize the circuit but cannot de-energize the circuit.

(from above reference to 700.12)
- 700.12 General Requirements.
- - (Jerry's note: Left off remainder of this section - this section and its sub-sections provide for allowable second power sources for emergency lighting, including exit signs.)
- - - (A) Storage Battery. (Jerry's note: Left off remainder of this section.)
- - - (B) Generator Set. (Jerry's note: Left off remainder of this section.)
- - - (C) Uninterruptible Power Supplies. (Jerry's note: Left off remainder of this section.)
- - - (D) Separate Service. (Jerry's note: Left off remainder of this section.)
- - - (E) Fuel Cell System. (Jerry's note: Left off remainder of this section.)
- - - (F) Unit Equipment. (Jerry's note: Left off remainder of this section.)