Can multi-core wires be used for comprehensive wiring of fire weak current system?

　　In the comprehensive wiring of fire protection weak current systems, multi-core wires can be used, but they need to be selected according to specific scenarios and specifications. The following is the detailed answer:

　　First, the applicability of multi-core wires

　　Advantage:

　　Anti-interference ability: Multi-core wires are composed of multiple conductors, which can effectively reduce external electromagnetic interference and are suitable for complex electromagnetic environments.

　　High tranSMission efficiency: supports parallel transmission of multiple signals to improve data transmission rate.

　　Long-distance transmission stability: Compared with single-core wires, multi-core wires experience less signal attenuation during long-distance transmission.

　　Applicable scenarios:

　　High-interference environments: such as large commercial buildings, industrial plants, and other places with complex electromagnetic environments.

　　Long-distance wiring: When the signal transmission distance is longer, the multi-core cable can provide more stable signal quality.

　　Multi-channel signal requirements: When multiple signals such as control, alarm, and communication need to be transmitted simultaneously, multi-core wires can simplify the wiring structure.

　　Second, fire protection weak current system wiring specification

　　Core cross-sectional area requirements:

　　Pipe laying: The minimum cross-sectional area of the insulated wire core is ≥ 1.0mm.

　　Wire trough/bridge laying: The minimum cross-sectional area of the insulated wire core is ≥ 0.75mm.

　　Multi-core cable: The minimum cross-sectional area of the core wire is ≥ 0.5mm ² (to meet the mechanical strength requirements).

　　Wire color and logo:

　　Color distinction: In the same project, wires for different purposes need to be distinguished by different colors (e.g., the positive electrode of the power cord is red, and the negative electrode is blue/black).

　　Clear identification: All lines should be clearly marked with their purpose and direction for easy maintenance and troubleshooting.

　　Wiring process requirements:

　　Avoid connectors: There should be no wire connectors in the wire pipe or the wire slot. The connectors should be welded in the junction box or connected with terminals.

　　Fire protection: Fire lines should be protected by metal pipes or fire-proof trough boxes, hidden in non-combustion structures, with a concrete protective layer thickness of ≥ 3cm.

　　Redundancy and isolation:

　　Redundant design: It is recommended to use dual or multi-route cabling for critical systems (e.g. fire alarms) to improve reliability.

　　Line isolation: Strong and weak lines should be laid separately to avoid electromagnetic interference.

　　III. Application cases of multi-core wires in fire protection

　　Fire alarm system:

　　Detector connection: smoke/temperature detectors, manual alarm buttons, etc. often use 2-core wires (signal bus).

　　Complex equipment, such as a manual alarm button with a telephone jack, may require four wires (signal + telephone cable).

　　Fire communication system:

　　Fire telephone: using 2-core wire (power supply + telephone line).

　　Fire broadcast: Use 2-core wires (signal + broadcast wires).

　　Linkage control system:

　　Fan/pump control: requires 5 or 4 wires (control + signal bus + power supply).

　　Input and output module: use 2-core wire (signal bus) + 2-core power cord.

　　IV. Precautions

　　Follow standards: Strictly follow national standards such as "Code for Design of Automatic Fire Alarm System" (GB50116) and "Code for Acceptance of Construction Quality of Building Electrical Engineering" (GB50303).

　　Material selection: Flame-retardant (ZR) and fire-resistant (NH) cables are preferred to ensure line safety in fire environments.

　　Comprehensive evaluation: According to factors such as building scale, system complexity, budget, etc., choose a single-core or multi-core line reasonably.

　　Summary: Multi-core wires can be used for comprehensive wiring of fire-fighting weak current systems, especially in long-distance and high-interference scenarios. However, it is necessary to strictly follow the specifications and choose the line type according to the actual needs to ensure the stability and reliability of the system.