InspectorJeff
Member
- Location
- Fountain Valley, CA., USA
Hello all,
See code section below. Both 2005 & 2008 NEC say the same thing. My interpretation is that (2) emergency branch circuits or equivalent should be designed into a required egress path such as an exit enclosure/stairwell. If (1) branch circuit was used for the whole stairwell and a ground fault occurred, the circuit breaker would trip rendering the stairwell in total darkness or at least dark enough to create a hazard when attempting to egress. Of course (2) sources of power should be available (Normal & Generator usually). I think the intent of this section actually adds another level of redundancy so that if the (1) panel or branch circuit fails, another will still be energized.
Need Comments.
Thanks .... Jeff
700.16 Emergency Illumination
Emergency illuminationshall include all required means of egress lighting, illuminatedexit signs, and all other lights specified as necessaryto provide required illumination.Emergency lighting systems shall be designed and installedso that the failure of any individual lighting element,such as the burning out of a lamp, cannot leave in totaldarkness any space that requires emergency illumination.Where high-intensity discharge lighting such as highandlow-pressure sodium, mercury vapor, and metal halideis used as the sole source of normal illumination, the emergencylighting system shall be required to operate untilnormal illumination has been restored.Exception: Alternative means that ensure emergency lighting
illumination level is maintained shall be permitted.See code section below. Both 2005 & 2008 NEC say the same thing. My interpretation is that (2) emergency branch circuits or equivalent should be designed into a required egress path such as an exit enclosure/stairwell. If (1) branch circuit was used for the whole stairwell and a ground fault occurred, the circuit breaker would trip rendering the stairwell in total darkness or at least dark enough to create a hazard when attempting to egress. Of course (2) sources of power should be available (Normal & Generator usually). I think the intent of this section actually adds another level of redundancy so that if the (1) panel or branch circuit fails, another will still be energized.
Need Comments.
Thanks .... Jeff
700.16 Emergency Illumination
Emergency illuminationshall include all required means of egress lighting, illuminatedexit signs, and all other lights specified as necessaryto provide required illumination.Emergency lighting systems shall be designed and installedso that the failure of any individual lighting element,such as the burning out of a lamp, cannot leave in totaldarkness any space that requires emergency illumination.Where high-intensity discharge lighting such as highandlow-pressure sodium, mercury vapor, and metal halideis used as the sole source of normal illumination, the emergencylighting system shall be required to operate untilnormal illumination has been restored.Exception: Alternative means that ensure emergency lighting