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Alarm: SLC and NAC circuits in the same raceway?

Alarm: SLC and NAC circuits in the same raceway?

Alarm: SLC and NAC circuits in the same raceway?

Hi to everybody.

Is it possible under the NFPA 72 to have different circuits in same raceways?...
Please see included sketch.
1. NAC and SLC in the same receway (EMT for example)?
2. Two different SLCs in the same raceway.?
3. Two different NACs in the same raceway?
Supossed class A go and return of same circuit are separated OK.

If no, what governs, NFPA70, or NFPA 72 class/integrity designations, please tell where it is addressed?

If yes, please tell if there is a limit (provided the size of the EMT is OK according to NFPA 70?

Thanks a lot in advance?

RE: Alarm: SLC and NAC circuits in the same raceway?

If you are asking a general question, I think your set up is ok.

Now the answer also might depend on the building you are putting it in and use of the building.
Plus what the contract requires.

You might look at NFPA 72 2016
Sections 12.4 and 12.5

72 does not mandate it, but tells you how to design to the different levels

I am not an engineer or designer

RE: Alarm: SLC and NAC circuits in the same raceway?

My answers are based on the 2013 edition of NFPA 72. Pathway Class designation is established by the designer, or the Engineer of Record if a specification was prepared. Neither the IFC nor NFPA 1 establish a requirement for Pathway Class designations. My response is going to be limited to conventional detection devices and audible and visual alarms based on your figure.

NFPA 72 only requires Class A and Class X circuits using physical conductors to be routed separately. The outbound and inbound conductors to the FACP or NAC power supply area allowed in the same cable assembly, enclosure under certain conditions prescribed in Section 12.3.7.

Section 12.5 also allows shared pathways depending on its survivability designation in NFPA 72 Section 12.4. For protected premises fire alarm systems the Pathway must be classified as part of the design per NFPA 72 Section 23.4.3. This includes IDCs and SLCs.

If you start dealing with Mass Notification, Area of Refuge Communications, In-Building Two-Way Radio Communication Enhancement systems or Two-Way Firefighter Telephone Communication systems, pathway survivability is required by various provisions in NFPA 72 Chapter 24. I have no experience with the NFPA 72 requirements for Public Emergency Alarm Reporting Systems but I am aware it has requirements for pathway survivability.

RE: Alarm: SLC and NAC circuits in the same raceway?


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