Are motion sensors permitted on emergency lighting circuits
- Thread starter steve66
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bdarnell
Senior Member
- Location
- Indianapolis, IN
- Occupation
- Retired Engineer
700.20 says no.
Yes, under the exception in 700.20
In a medical distribution facility, we [combined] normal and emergency lighting circuits from separate systems/conduits into a common box with EM relay which switched both systems from a common OC.
The EM relay defaults to a NC contact upon normal power failure allowing the EM light to remain on.
In a medical distribution facility, we [combined] normal and emergency lighting circuits from separate systems/conduits into a common box with EM relay which switched both systems from a common OC
The EM relay defaults to a NC contact upon normal power failure allowing the EM light
bdarnell
Senior Member
- Location
- Indianapolis, IN
- Occupation
- Retired Engineer
Gmack said:
Agreed. As long as you meet the requirements of the exception.
- Location
- Massachusetts
Steve IMO you can control the emergency lighting most anyway you want as long as it will always come back on automatically if the utility fails as gmack was indicating.
A normally closed contactor or a relay as an override switch is a reliable way to do this.
I have also done this through energy management systems using normally open contacts which means the EMS system must be operational to provide the lighting, IMO leaves to much to go wrong.
A few large department stores we wired had a key switch that the last person out used to power the store down. This switch literally shut the entire place down, exit signs, emergency and normal lighting, receptacle outlets all off.
If the utility failed or the fire alarm tripped the emergency systems would come back on.
A normally closed contactor or a relay as an override switch is a reliable way to do this.
I have also done this through energy management systems using normally open contacts which means the EMS system must be operational to provide the lighting, IMO leaves to much to go wrong.
A few large department stores we wired had a key switch that the last person out used to power the store down. This switch literally shut the entire place down, exit signs, emergency and normal lighting, receptacle outlets all off.
If the utility failed or the fire alarm tripped the emergency systems would come back on.
In the application I saw (on blueprints), there was no aux. switch. Only motion sensors. If the motion sensors didn't see someone, the lights didn't come on. If both sensors detected a person, both normal and emergency lights would come on when you walked into the room.
I rejected it based on 700.3 - All equipment shall be approved for use on emergency circuits.
I would accept it if there was something that bypassed the motion sensor during a power failure.
Steve
I rejected it based on 700.3 - All equipment shall be approved for use on emergency circuits.
I would accept it if there was something that bypassed the motion sensor during a power failure.
Steve
That pretty much settles it Roger.
7.8.1.2.2 Automatic, motion sensor?type lighting switches shall be permitted within the means of egress, provided that the switch controllers are equipped for fail-safe operation, the illumination timers are set for a minimum 15-minute duration, and the motion sensor is activated by any occupant movement in the area served by the lighting units.
But, I'm not sure how one would verify they are equipped for fail safe operation.
Steve
7.8.1.2.2 Automatic, motion sensor?type lighting switches shall be permitted within the means of egress, provided that the switch controllers are equipped for fail-safe operation, the illumination timers are set for a minimum 15-minute duration, and the motion sensor is activated by any occupant movement in the area served by the lighting units.
But, I'm not sure how one would verify they are equipped for fail safe operation.
Steve
But, I'm not sure how one would verify they are equipped for fail safe operationcolosparker
Senior Member
Do motion sensors work in a smoke filled room? If people are crawling on the floor (in the case of a fire) will they activate the sensors for the emergency lighting? Is it worth the $100 for the sensor to save the small wattage it costs to leave the emergency lights on?
These are common sense questions to ask overzealous energy management companies, energy managers, etc.
Whenever I find a $100 motion sensor that failed (usually last a couple of years if we are lucky) I replace it with a $4 switch. Save the facility more money than the motion sensor did in it's short life.
These are common sense questions to ask overzealous energy management companies, energy managers, etc.
Whenever I find a $100 motion sensor that failed (usually last a couple of years if we are lucky) I replace it with a $4 switch. Save the facility more money than the motion sensor did in it's short life.
- Location
- Massachusetts
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In many places saving energy is not optional, it is required by energy codes.
Not sure how NFPA 101 comes into play if it is not adopted in your area. :?
In many places saving energy is not optional, it is required by energy codes.
Not sure how NFPA 101 comes into play if it is not adopted in your area. :?
I agree Iwire, energy saving systems are federally mandated for most larger complexes/buildings. I worked on a 20 screen theater that had OS in the stairwells. Think about that.
They are everywhere these days. But I wasn't talking about switch box type sensors. But rather ceiling mounted types integrated into a programmable EMS/switched relay panels with low voltage remote addressable overrides/switches.
As to seeing thru smoke and such, the OC's [ceiling type sensor] we installed had a "sonic" component with IR capability. I cannot vouch for long term reliability. As I stated above, they spec them in the stairwells too. So someone believes in them.
They come in a package with all sensors and relays complete with UL listing. The sensors themselves are low voltage signal only and do not switch any line voltage.
The EM relays both panel and "box mount" handle all that. All in all it works quite well.
They are everywhere these days. But I wasn't talking about switch box type sensors. But rather ceiling mounted types integrated into a programmable EMS/switched relay
As to seeing thru smoke and such, the OC's [ceiling type sensor] we installed had a "sonic" component with IR capability. I cannot vouch for long term reliability. As I stated above, they spec them in the stairwells too. So someone believes in them.
They come in a package with all sensors and relays complete with UL listing. The sensors themselves are low voltage signal only and do not switch any line voltage.
The EM relays both panel and "box mount" handle all that. All in all it works quite well.
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