My Emergency Lighting Change

[Dean83169]

I have worked on many large commercial and institutional projects. Most do not have emergency generators but my proposal would be directed to the portion of the code which relates to "if you have one circuit, the emergency lighting load must be tied to that circuit or if you have more then three you may pick one of the lines to tie to" I do not have the exact quote or article number.
My suggestion to change this is to monitor all legs within that room as so if ANY of the circuits trips then the emergency lighting would have to turn on.
I only say this due to the fact that you either need to have all the lights on or at least that circuit you tied to on in order to have emergency lighting. In the day of saving energy and the engineers installing to many lights, most cases you only use half the amount which could possibly result in no emergency lighting. I think it should change to have to monitor all phases of lighting in such rooms with multiple circuits. Any comments?

 

[George Stolz]

I think this is purely a design issue. In most cases, the designer will connect the emergency fixtures to the general lighting circuit in the area, if ancillary lighting is also present on a seperate circuit.

Such a change would be too restrictive to justify, IMO. Show me a body count.

 

[W6SJK]

I have worked on many large commercial and institutional projects. Most do not have emergency generators but my proposal would be directed to the portion of the code which relates to "if you have one circuit, the emergency lighting load must be tied to that circuit or if you have more then three you may pick one of the lines to tie to" I do not have the exact quote or article number.

If 3 or more circuits are used, you don't have to use one of them. You just have to tie to the same PANEL. 700.12 F

 

[don_resqcapt19]

The idea behind the existing rule is very reasonable. If the area lighting is served by 3 or more branch circuits, the only likely reason for the the area to become completely dark is loss of the power supply to the panel that feeds the ligting circuits. If that happens and the unit lighting equipment is fed from a branch circuit in the same panel as required by the code rule, then the emergency light will come on. I see no reason for a code change.
Don

 

[Dean83169]

The reason I say this is even if you tap off the panel it still does not protect you in the event of a tripped circuit for that room. With one circuit then its ok cause if it trips then you have em lighting but if you have 3 circuits and you tap one or the panel then all the lights would have to be on to provide protection or so called illumination. I feel if its about life safety then depending on how many circuits you have you should have to monitor all circuits that provide lighting to that room. A few schools that I have done didnt want the responsibility since having 3 circuits of lighting per room and only tapping one. What if the room had 3 circuits, you have the "A" phase of lights on but you tapped the em off the "B or C" phase or even the panel that provides the circuits. If the "A" trips now you have no em lighting provided for that room, if your child was in that room and had gotten hurt trying to get out because of no lighting, who's responsibilty is it and is it a case for a suit? I think its about life safety, I think it should be changed to monitor all circuits that provide illumination in that room.

 

[jtester]

......What if the room had 3 circuits, you have the "A" phase of lights on but you tapped the em off the "B or C" phase or even the panel that provides the circuits. If the "A" trips now you have no em lighting provided for that room, if your child was in that room and had gotten hurt trying to get out because of no lighting, ......

If A phase trips, you still have the lighting provided by B and C, I don't understand how the child is hurt because there "is no lighting".

Jim T

 

[don_resqcapt19]

Dean,

If the "A" trips now you have no em lighting provided for that room, if your child was in that room and had gotten hurt trying to get out because of no lighting, who's responsibilty is it and is it a case for a suit?

How could that happen? The only time you can put the unit lighting equipment on a circuit that does not serve the lighting in that area is where there is at least 3 lighting circuits serving that area. If you are saying that all three lighting circuits could be on A phase and for some reason A phase is lost, then it would be possible to put the area in the dark. The loss of a single phase is rare, but does happen. Maybe a better code change would require that the 3 or more lighting circuits in the area be served by all of the phases in the panel.
Don
Don

 

[Dean83169]

No, maybe I am not making this instance clear enough which could be my fault.
If you were to run a 3 wire homerun due to having 3 circuits of lighting in that room. Now you can either tap off one of those circuits (A,B,C Phase) which is derived from the same panel. In this case of not having all 3 circuits of lighting on in that room, but only 1 circuit which lets say is the "A" phase, but just so happens that the EM lighting is on the "B" or the "C" phase. A ballast burns out on the phase "A" circuit causing circuit "A" to trip which the end result is a dark room.
My recommendation was to monitor all CIRCUITS that provide lighting to that room. So at no point any under any circumstance you will be without EM lighting. This is just my thinking and my opinion.

 

[don_resqcapt19]

Dean,
That would be somewhat rare and not really practical. As such it is a design issue and not a code issue.
Don

 

[Dean83169]

I understand. I suggest it to the clients and they all have opted to install the relays for their own assurance that their children and employee's are protected. I guess its better to be safe then sorry, it only takes one instance, a small price for a few relays.

 

[don_resqcapt19]

Dean,

I suggest it to the clients and they all have opted to install the relays for their own assurance that their children and employee's are protected. I guess its better to be safe then sorry, it only takes one instance, a small price for a few relays.

I fail to understand the exteme danger when a single lighting circuit is out of service. I would expect that there is someone in the room who knows where the switches are and can turn one of the other circuits on.
Don