Yes, in general, running both the initiating device circuit (IDC) for the pull station and the notification appliance circuit (NAC) for the speaker strobe in the same conduit is allowed by most codes, including the National Electrical Code (NEC) and NFPA 72 (National Fire Alarm and Signaling Code), provided certain conditions are met. Here's a breakdown of the considerations

Reasons why it's generally allowed:
Common Function

Both circuits are related to the fire alarm system and contribute to its overall operation.

Wiring Method

Fire alarm circuits, both IDCs and NACs, are typically run using wiring methods permitted by the NEC, such as EMT (electrical metallic tubing), rigid conduit, or MC (metal-clad) cable. These methods are suitable for containing multiple circuits.

Code Compliance

The NEC and NFPA 72 do not generally prohibit mixing IDCs and NACs within the same conduit, as long as specific requirements for wire type, insulation, and separation are followed.

Important Considerations and Code Requirements (consult local codes for definitive answers)



Wire Type and Insulation

The conductors used for both the IDC and NAC circuits must be rated for the voltage and temperature conditions within the conduit. They typically must be THHN/THWN or similar rated conductors.

Voltage

Ensure the voltage ratings of all conductors are compatible and meet the requirements of both circuits. Typically, fire alarm circuits are low voltage (24V DC), but it's crucial to verify.

Power-Limited vs. Non-Power-Limited

A critical factor is whether the fire alarm circuits are classified as power-limited or non-power-limited. Power-limited fire alarm circuits (PLFA) have specific voltage and current limitations, usually provided by the fire alarm control panel.

If both circuits are PLFA, they can generally be run in the same conduit. If either circuit is non-power-limited, separation requirements may apply. This means using a barrier within the conduit or running the circuits in separate conduits. Non-power-limited circuits are less common in modern fire alarm systems, but it's essential to verify. NFPA 72 Requirements

NFPA 72 provides specific guidance on wiring methods and separation requirements for fire alarm circuits. It emphasizes the reliability and survivability of the fire alarm system.

Listing and Labeling

All components, including the conduit and conductors, must be listed and labeled for their intended use and meet the requirements of the applicable standards.

Ampacity

Ensure the conductors are appropriately sized for the maximum current they will carry, considering derating factors if multiple conductors are in the same conduit.

Mechanical Protection

The conduit must provide adequate mechanical protection for the conductors.

Local Amendments

Always check for any local amendments to the NEC or NFPA 72 that may impose stricter requirements.

Practical Advice



Consult the Fire Alarm System Manufacturer's Instructions

The manufacturer's installation instructions often provide specific guidance on wiring methods and circuit separation.

AHJ Approval

When in doubt, consult with the local Authority Having Jurisdiction (AHJ), such as the fire marshal or building inspector, for clarification and approval.

Documentation

Keep detailed records of the wiring methods used and ensure they comply with all applicable codes and standards.

In Summary:

Running IDCs and NACs in the same conduit is generally permitted as long as you follow the requirements for wire type, insulation, voltage, power-limited vs. non-power-limited classification, and ampacity, and provided that the selected method is compliant with the NEC, NFPA 72, and any local amendments. Always prioritize safety and code compliance. When in doubt, consult the AHJ and the fire alarm system manufacturer. Flag for review