Fire Alarm Power must come from main panel?

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mkgrady

Senior Member
Location
Massachusetts
In this one family home that has a security and fire alarm system I failed inspection because the systems are powered from a general purpose receptacle. I did not know of the requirement which I have since found in 760.41. It does not seem to apply to security systems though. I don't even know how to tell if the FA is non-power limited. Both systems were installed by another contractor, who simply told me he needed an outlet for his systems.

I told the inspector I would resolve the problem by running to the pool subpanel which is about three feet away. He said it must come from the main panel because if someone shuts off the pool subpanel it will kill power to the two systems. Running a circuit back to the main panel would be very difficult so I don't want to do it. I don't think there would be any good reason to shut down the pool panel, and if they did, the loss of power alarm is deafening, so I think they would just turn it back on. But in any case, I don't believe there is any code reason not to feed the security and fire systems from the pool panel.

Is the inspector correct?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
In this one family home that has a security and fire alarm system I failed inspection because the systems are powered from a general purpose receptacle. I did not know of the requirement which I have since found in 760.41. It does not seem to apply to security systems though. I don't even know how to tell if the FA is non-power limited. Both systems were installed by another contractor, who simply told me he needed an outlet for his systems.

I told the inspector I would resolve the problem by running to the pool subpanel which is about three feet away. He said it must come from the main panel because if someone shuts off the pool subpanel it will kill power to the two systems. Running a circuit back to the main panel would be very difficult so I don't want to do it. I don't think there would be any good reason to shut down the pool panel, and if they did, the loss of power alarm is deafening, so I think they would just turn it back on. But in any case, I don't believe there is any code reason not to feed the security and fire systems from the pool panel.

Is the inspector correct?

He may be, but neither the NEC nor NFPA 72 explicitly says this. It would be based on a local requirement. The general requirement is for a "dedicated" circuit. It could be argued that a sub panel does not meet that requirement because the breaker feeding the sub panel is feeding more than one load, whether the breaker is at the sub panel or back at the main panel.
 

kwired

Electron manager
Location
NE Nebraska
If someone shuts off the main panel you still lose power to the alarm system. Chances are it has a backup battery and possibly gives a trouble alert should the AC power be lost.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
IMHO, except for cases such as legacy three wire range circuits were the origin in some cases must be the service equipment, the word dedicated refers only to the branch portion of the circuit.
Otherwise where do you draw the line?
Separate service? Separate distribution transformer? Separate POCO?
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I took another look at NFPA 72. Under 11.6.3 (2007 edition), for a residential system, you can get AC power from either a dedicated branch circuit or the unswitched side of a power and lighting circuit. It also doesn't have to be hardwired, as long as you have a means to secure the "brick" from being accidentally dislodged.
 

iwire

Moderator
Staff member
Location
Massachusetts
The general requirement is for a "dedicated" circuit. It could be argued that a sub panel does not meet that requirement because the breaker feeding the sub panel is feeding more than one load, whether the breaker is at the sub panel or back at the main panel.

Using that argument would mean there is never a dedicated circuit unless you install a seperate service disconnecting means for each dedicated circuit.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Using that argument would mean there is never a dedicated circuit unless you install a seperate service disconnecting means for each dedicated circuit.

Which is probably how NYC got to where it is regarding power for fire alarm control panels. I agree that it can get ridiculous, but I don't know where you should draw the line. Maybe at the end of the season, they kill everything to the pool. Now the sub panel has to stay on. I just don't know.
 

charlie b

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Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I don't believe there is any requirement, not in the NEC at least, that a single family home even have a fire alarm system. It certainly is not required to have a security system. So basically, why should the inspector care if it does not work? :?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I don't believe there is any requirement, not in the NEC at least, that a single family home even have a fire alarm system. It certainly is not required to have a security system. So basically, why should the inspector care if it does not work? :?

For the same reason that you are not required to have a wire EGC in a compliant metallic raceway, but if you choose to put one in it must obey the sizing rules?
 

mkgrady

Senior Member
Location
Massachusetts
I don't believe there is any requirement, not in the NEC at least, that a single family home even have a fire alarm system. It certainly is not required to have a security system. So basically, why should the inspector care if it does not work? :?

The house is too large to use standard hard wired smoke detectors so they had to go with a system of wired low voltage detectors. I don't even know if 760.41 applies nor do I know how to find out.
 

kwired

Electron manager
Location
NE Nebraska
Which is probably how NYC got to where it is regarding power for fire alarm control panels. I agree that it can get ridiculous, but I don't know where you should draw the line. Maybe at the end of the season, they kill everything to the pool. Now the sub panel has to stay on. I just don't know.
Many school buildings I have been in that had fire alarms installed/updated somewhere beteen 1965 -1985 seem to always have a 30 amp fused disconnect tapped to the supply side of the service disconnecting means (usually with just a 10 AWG copper in the same lug port as a much larger service conductor) and this disconnect usually supplies the fire alarm. Some also have another similar supplied disconnect that does emergency egress lighting units.

I think it was done that way because of misunderstandings of what was meant by "dedicated circuit", maybe even by fire marshal more so then an electrical inspector. It is almost automatic that you will find a facility set up that way if the last major change to those systems or the main service was in that time frame.
 

iwire

Moderator
Staff member
Location
Massachusetts
Many school buildings I have been in that had fire alarms installed/updated somewhere beteen 1965 -1985 seem to always have a 30 amp fused disconnect tapped to the supply side of the service disconnecting means (usually with just a 10 AWG copper in the same lug port as a much larger service conductor) and this disconnect usually supplies the fire alarm. Some also have another similar supplied disconnect that does emergency egress lighting units.

I think it was done that way because of misunderstandings of what was meant by "dedicated circuit", maybe even by fire marshal more so then an electrical inspector. It is almost automatic that you will find a facility set up that way if the last major change to those systems or the main service was in that time frame.


I would see the same set up in buildings of that time frame to supply power strictly for an electric bell that would ring if there was water flow in the main sprinkler line. Typically the disconnect switch was painted red.

But is no longer 1985 and we feed fire alarm systems from sub panels all the time. Every building that we do that has an emergency generator has the fire panel supplied from one of the emergency panels. This is often a few layers away from the service disconnect.


480Y/277 VOLT UTILITY > SERVICE DISCONNECT MAIN BREAKER MDP > ATS FEEDER BREAKER > 480Y/277 VOLT EMERGENCY PANEL MAIN BREAKER > TRANSFORMER FEEDER BREAKER > TRANSFORMER > 208Y/120 VOLT EMERGENCY PANEL MAIN BREAKER > FACP BRANCH CIRCUIT BREAKER > FACP
 
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