What is the most effective way to satisfy the two lamp requirement for emergency lighting for outdoor areas called out in the NEC?
A. The clause you refer to comes from article 700.16 in the NEC. The middle paragraph reads: “Emergency lighting systems shall be designed and installed so that the failure of any individual element, such as the burning out of a lamp, cannot leave in total darkness any space that requires emergency illumination”. While a lot of attention has been given to the middle of the sentence, referring to the failure of a lamp, there is much more to this requirement. First, the intent of the NFPA was to address interior spaces with two or more exits that require emergency lighting and where an emergency generator is provided for egress illumination. The goal was to require more than one fixture in that interior space to receive emergency generator power, thus, eliminating the potential to have that space left in total darkness should the luminaire (or lamp) fail. Secondly, the requirement specifically calls out the words “systems” and “total darkness”. These words carry the same, if not more, im
