725 and 760, class 1 circuitry

[Isaiah]

Does the definition of Class 1 circuitry remain the same regardless of the whether its remote control and signaling or fire alarm systems circuits?


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[don_resqcapt19]

The wiring methods do, but I don't think that Article 760 has any Class 1 circuits. As I recall it has non-power limited fire alarm circuits, which are installed using Class 1 wiring methods, and power limited fire alarm circuits which are installed using wiring methods more like what would be used for an Article 725 Class 2 circuit.

Unless you are working on an old fire alarm system, it would be very rare to see a non-power limited fire alarm circuit.

 

[Isaiah]

The wiring methods do, but I don't think that Article 760 has any Class 1 circuits. As I recall it has non-power limited fire alarm circuits, which are installed using Class 1 wiring methods, and power limited fire alarm circuits which are installed using wiring methods more like what would be used for an Article 725 Class 2 circuit.

Unless you are working on an old fire alarm system, it would be very rare to see a non-power limited fire alarm circuit.

Great feedback Don.
So basically PLFA has lesser insulation (300V?) and has to be routed in separate conduit, right? But NPLFA (600V?) can be routed with other circuits?
It also seems non conductive FO can be routed with PLFA or NPLFA.


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[don_resqcapt19]

PLFA does not have to be by itself, as it can be mixed with other limited energy cables per 760.139. However specs often require the FA to be in its own raceway.
NPLFA can only be in the same cable or raceway with power conductors where the power conductors are connected to the fire alarm equipment. 760.48.

 

[Isaiah]

PLFA does not have to be by itself, as it can be mixed with other limited energy cables per 760.139. However specs often require the FA to be in its own raceway.
NPLFA can only be in the same cable or raceway with power conductors where the power conductors are connected to the fire alarm equipment. 760.48.

Thanks again Don! Very useful info as usual


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[Isaiah]

Thanks again Don! Very useful info as usual


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Don
So it goes without saying e.g., 120VAC Power cannot be routed in the same raceway with PLFA even if it is functionally associated with same equipment since a fault on the 120VAC cable could damage the PLFA, due to its lesser insulation?


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[Isaiah]

PLFA does not have to be by itself, as it can be mixed with other limited energy cables per 760.139. However specs often require the FA to be in its own raceway.
NPLFA can only be in the same cable or raceway with power conductors where the power conductors are connected to the fire alarm equipment. 760.48.

Don what if the PLFA is installed within a protective duct in the conduit? Would this suffice as a barrier if routed with say, 120Vac power ?


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[don_resqcapt19]

Don what if the PLFA is installed within a protective duct in the conduit? Would this suffice as a barrier if routed with say, 120Vac power ?


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That would probably be acceptable in accordance with 760.136(G), but only your AHJ knows for sure.

 

[Isaiah]

That would probably be acceptable in accordance with 760.136(G), but only your AHJ knows for sure.

Good point!


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