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Wiring & Circuitry
Fire alarm circuits carry both power and signals between the panel and devices. Circuit class and pathway survivability determine how the system behaves during faults, and conductor selection must respect voltage drop and separation requirements.
- Differentiate Class A (redundant/loop) and Class B (single-path) circuits and how each behaves on a break.
- Explain the difference between an initiating device circuit (IDC) and a notification appliance circuit (NAC).
- Describe how an addressable signaling line circuit (SLC) lets the panel identify the exact device that activated.
Modules 1–3 are open to everyone. Create a free account to keep going:
- All 17 Learning Center modules with NFPA 72 code sections
- Module quizzes, quick checks and the capstone
- Your progress, scores and streak saved across devices
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Additional Resources
Code References
Adopted Code Editions — Verify Locally
Always confirm the NFPA 72 and NFPA 70 (NEC) editions adopted by your jurisdiction before using any concept from this trainer.
Best Practices
Working With Your AHJ
Engage the Authority Having Jurisdiction early. Local amendments and interpretations govern the final design.