Article 700.16

[RETKWA]

Emergency lighting systems shall be designed so that failure of any individual lighting element such a burning out of a lamp shall not leave in darkness any space that requires emergency illumination.

My question is, if I use a (1) LED wall pack over an egress door and the lamps are wired in parallel on the boards does the fixture need (2) drivers and separate boards?

 

[IMFOTP]

This question has been asked a couple times before, search the forum. You'll probabwly get a fe different answers. My opinion is that 700.16 is easily interpreted multiple ways.

I always question what is meant by "lighting element". The code gives an example of a lamp. I think of it as a "lighting element" is the part of the fixture that turns electrical energy into electromagnetic radiation (light). Thinking of it this way...the individual LED is the lighting element, not the driver, not the wiring, not the board. Just the individual LED. So if you have a board with multiple LEDs do you satisfy 700.16? I think so.

Alternatively if you assume you need (2) of everything, where does it stop. Two drivers, two boards...well we'll need two battery packs, or two emergency circuits then two generators. Tongue in cheek but it can be difficult to draw the line.

Bottom line you probably need to ask the AHJ, the ambiguity in this part of 700 seems to be interpreted differently depending on who talk to.

 

[steve66]

I agree with the previous response. To me a lighting element is a lamp or LED.

However, I do believe there are some exterior fixtures you can get with two separate drivers for emergency lighting to satisfy inspectors who are a little more strict in their interpretation.

Like this one:


http://www.acuitybrands.com/product...onia_Lighting/114968/document/WSR-LED_pdf.pdf

All ELCW configurations include an independent secondary driver with an integral relay to immediately detect AC power loss. Dual light engines are wired in parallel so both engines operate in emergency mode and provide additional component redundancy. These design features meet various interpretations of
NFPA 70/NEC 2008 -
700.16

 

[n1ist]

That fixture does have two drivers, however it sounds like one is AC powered for normal use and one is battery-powered for emergency use. The relay switches the light engine between the two drivers upon power loss.