The "Lifeline" for Stable Transmission of Fire Alarm Systems

The "Lifeline" for Stable Transmission of Fire Alarm Systems

Shielded VS Unshielded Fire Alarm Cables: How to Select for Better

In fire alarm systems, fire alarm cables serve as the last line of defense for life-saving signals. Any signal interruption or false alarm can lead to catastrophic consequences. Many contractors struggle with the choice: shielded or unshielded fire alarm cables? This article helps you make the right decision based on four dimensions: interference environment, transmission distance, code requirements, and cost.

1. Core Differences: Shielded vs. Unshielded

Unshielded Fire Alarm Cables

Structure: Conductor + Insulation + Sheath, no shielding layerAdvantages: Low cost, flexible for wiring, stable pricingApplication: Conventional projects with low interference, short distance, and no mandatory shielding requirements per codes

Shielded Fire Alarm Cables

Structure: Added aluminum foil/braided shielding layer + grounding wireAdvantages: Strong anti-interference, stable signal, prevents false/non-alarmsApplication: Strong electromagnetic environments, long-distance wiring, high-grade fire protection projects

2. When Must Shielded Fire Alarm Cables Be Used?

Shielded type is highly recommended if any of the following conditions are met:

· Installed in the same cable tray/conduit as high-voltage cables (220V/380V power lines)

· Near factories, equipment rooms, substations, elevators (high electromagnetic interference)

· Long-distance wiring (over 100 meters, signal prone to attenuation)

· Hospitals, data centers, intelligent buildings (high reliability requirements)

· Local codes/drawings explicitly specify F/PLTC or Shielded type

The shielding layer effectively blocks:

· Electromagnetic Interference (EMI)

· Radio Frequency Interference (RFI)

· Leakage and crosstalk, avoiding fatal issues such as false alarms, non-alarms, and mainframe failures

3. When Can Unshielded Fire Alarm Cables Be Used?

Unshielded type is applicable (more economical) under these conditions:

· Low-interference environments such as residences, small shops, and offices

· Short wiring distance (<50–80 meters)

· Separate wiring for strong and weak currents, different conduits/trays

· Limited project budget and no mandatory shielding per codes

Unshielded cables offer better cost performance and easier construction, making them the mainstream choice for conventional fire protection projects.

4. One-Sentence Selection Summary

Low interference + short distance → Unshielded fire alarm cables (economical and practical)High interference + long distance + high standards → Shielded fire alarm cables (safe and reliable)