Emergency lighting on an optional standby generator

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Grouch1980

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Location
New York, NY
Hi all,
I checked through other threads, but none that specifically answer the question that i have (or maybe one does, I just missed it):

We are using a voluntary generator for a building, it is not a code required generator... therefore, this generator falls under Article 702 of the NEC... it is an optional standby generator (please correct me if i'm wrong). So that means all loads connected to the generator are considered optional standby, and can all be connected via one automatic transfer switch (the optional standby ATS). Can the lights which need generator power also be connected to this same ATS switch? If so, do the lights need integral emergency ballasts? I'm asking because these lights are considered emergency lights... and having them connected to an optional standby ATS, as opposed to a life safety ATS, implies that they are not EM lights... and so now need integral emergency ballasts (or do they not??).

Thanks!
 

Grouch1980

Senior Member
Location
New York, NY
I found this online:

http://www.nyc.gov/html/dob/html/codes_and_reference_materials/tppn0107.shtml

it states:

"Recognizing that the installation of emergency generators can be very beneficial to the building and in order to encourage voluntary installations, only the following life safety loads shall be required to be connected to such generators:

  1. Emergency lighting (unless supported by battery packs of adequate capacity), including stairway lighting.
  2. Fire alarm system.
  3. One elevator serving all floors of the building."

seems like you don't need integral emergency ballasts on lights connected to an optional standby transfer switch.

any feedback is welcome!
 

charlie b

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I agree with Don. If there is a requirement for an "emergency" light (e.g., to illuminate the path of egress), then there needs to be an emergency (article 700) power source. It is OK to put those lights downstream of an optional standby ATS. That would actually give you an additional source of power, which is not an evil thing. But it would not satisfy the requirement for an emergency power source. So they would also need an emergency battery backup or some other article 700 power source.
 

ron

Senior Member

That TPPN is from 2007. The codes have progressed, and now similar requirements are found in the building code for NYC. http://www.nyc.gov/html/dob/apps/pd...apter_27_Electrical.pdf&section=conscode_2014

2702.4 Required loads for optional standby power systems.
In addition to any other loads, optional standby power systems shall be capable of providing power to the following systems upon failure of the normal power supply or the emergency or standby power system:
1. Emergency lighting;
2. Fire alarm systems; and
3. Elevators as follows:
3.1 For Group R-2 occupancies in buildings greater than 125 feet (38 100 mm) in height, at least one elevator serving all floors, or one elevator per bank where different banks serve different portions of the building; or
3.2 For all other buildings having occupied floors located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access, at least one elevator that serves all floors.
 

LIM

Member
Location
NC
You have two options:

1. Provide a Article 700 generator/transfer switch arrangement and connect the emergency lights through the transfer switch.
2. Provide emergency lights per 700.12(F) and let the optional generator (702) be just that. The optional generator will not become a 700 if you back up the 700.12(f) lights with it. They are covered for the required 90 min by the battery, everything beyond that is a bonus.
 

Grouch1980

Senior Member
Location
New York, NY
Thanks everyone. That actually clears it up a lot. So with a voluntary generator, i would still need either a dedicated transfer switch for the emergency lights (to satisfy article 700), OR integral battery packs for each light if they are fed via the optional standby ATS. It's much clearer now.
 

don_resqcapt19

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Location
Illinois
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retired electrician
Thanks everyone. That actually clears it up a lot. ... OR integral battery packs for each light if they are fed via the optional standby ATS. It's much clearer now.
You can't just feed the battery back up lights with generator power ... you would have to feed the normal lighting circuit that the battery units are connected to.
 

don_resqcapt19

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Location
Illinois
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hmm... that i didn't follow... can you explain that again?
Battery em lights are required to be fed from the circuit that provides the normal lighting for the area. You would have to feed that normal lighting circuit from your generator. 700.12(F)(2)(3)
 

GoldDigger

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Placerville, CA, USA
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Battery em lights are required to be fed from the circuit that provides the normal lighting for the area. You would have to feed that normal lighting circuit from your generator. 700.12(F)(2)(3)
Or, more verbosely, fed from the transfer switch on the generator output.
Still, not just a normal panel circuit.
And one might argue that all of the other lights in the area would also have to come from the same circuit.
But probably more to the point, if the em lights are switched off, then they need to turn on when power to the rest of the area lighting is lost.
Typically battery backup em lights will have one (switched) primary power input and one control-only sensing input for the normal power source. The latter must NOT be fed from the generator.
 
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iwire

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Location
Massachusetts
Typically battery backup em lights will have one (switched) primary power input and one control-only sensing input for the normal power source. The latter must NOT be fed from the generator.

Both inputs to the fixture must come from the same panel. There is no choice in that. There is only one neutral connection for both inputs.

The only choice is that one of the inputs can be be run through a switching device and the other must be on 24/7.
 

GoldDigger

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Both inputs to the fixture must come from the same panel. There is no choice in that. There is only one neutral connection for both inputs.

The only choice is that one of the inputs can be be run through a switching device and the other must be on 24/7.
Looks like you have that part nailed down

Next question is whether the em equipped fixtures have to be supplied from the same panel as all the other lighting for that area. The wording can be taken to imply that.
Which would in turn imply that all lighting serving a given area must originate from a single panel.

Going back for a moment to the first question, I suppose you could use a single circuit transfer contactor and thereby have both normal and backed up circuits come from the same panel?
 

iwire

Moderator
Staff member
Location
Massachusetts
Looks like you have that part nailed down

I install a lot of them and have been involved with fixing them when the construction crew runs two-12/2 cables to each instead of a single 12/3 cable for both the switched and the constant feeds.


Next question is whether the em equipped fixtures have to be supplied from the same panel as all the other lighting for that area. The wording can be taken to imply that.
Which would in turn imply that all lighting serving a given area must originate from a single panel.

The NEC requires the unit equipment to be supplied from the same circuit as the lighting in the area it serves. I don't see any way to read that as coming from the same panel.

There is an exception for large open areas where the lighting is supplied from multiple circuits.


Here is part of 700.12(F)

.... The branch circuit feeding
the unit equipment shall be the same branch circuit as that
serving the normal lighting in the area and connected ahead
of any local switches. .....


Exception No. 1: In a separate and uninterrupted area
supplied by a minimum of three normal lighting circuits, a
separate branch circuit for unit equipment shall be permitted
if it originates from the same panelboard as that of the
normal lighting circuits and is provided with a lock-on
feature.




Going back for a moment to the first question, I suppose you could use a single circuit transfer contactor and thereby have both normal and backed up circuits come from the same panel?

I am not following you here.
 
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