Definition of Structured Cabling Cables: Structured cabling system cables refer to materials used for power, communication, and related transmission applications. There is no strict boundary between "wires" and "cables." Generally, products with fewer cores, smaller diameters, and simpler structures are called wires; those without insulation are called bare wires, and others are called cables. Conductors with larger cross-sectional areas (greater than 6 square millimeters) are called large wires, and those with smaller cross-sectional areas (less than or equal to 6 square millimeters) are called small wires. Insulated wires are also called building wires. Wires and cables mainly include bare wires, magnet wires, insulated wires for motors and electrical appliances, power cables, communication cables, and optical fibers.
I. How to select cables for a structured cabling system
Despite the rapid urbanization in China, the construction industry remains vibrant. Today's society has embraced the smart city model, and intelligent management has quietly permeated public facilities, high-rise buildings, and even residential communities. The buildings of the future will undoubtedly be intelligent buildings, and intelligent management has become an indispensable part of our lives.
In today's society, intelligent buildings have become an inevitable trend in the construction industry. According to the "2013-2017 China Intelligent Building Industry Development Prospect and Investment Strategy Planning Analysis Report", the development of intelligent buildings in China has been rapid, with an annual growth rate of 20%. It first exceeded 20 billion yuan in 2005 and reached 86.1 billion yuan in 2012.
In this trend of rapid development of intelligent technology, the nervous system of intelligent buildings—the integrated cabling system—has become even more important and indispensable. In the ordinary construction industry, communication cables are infrastructure; but in intelligent buildings, the integrated cabling system becomes the most critical and fundamental part.
The planning, design, construction, installation, maintenance, and use of building projects are all closely related to structured cabling. As the nervous system of intelligent buildings, it undertakes the important task of collecting and transmitting information, becoming a bridge for our communication.
In other words, structured cabling systems play a crucial role in intelligent buildings, closely connecting communication equipment, computers, and other facilities, providing excellent support for high-level intelligence. Therefore, fire prevention becomes a particularly important factor to consider. In the event of a fire within a building, the cables will inevitably release large amounts of heat and toxic gases, posing serious safety hazards and dangers.
It is not hard to imagine that in the several major fire accidents that have occurred in China in recent years, the tragedy occurred because the cables released toxic gases at high temperatures, and the heat and smoke generated during the combustion caused the trapped victims to be unable to breathe and ultimately unable to escape.
Therefore, communication cables in the current domestic market are classified into different grades, the difference being the material of the cable sheath. The "Integrated Cabling Engineering Design Standard GB50311-2007" (2007) classifies cables into fire-resistant and environmentally friendly grades. According to this standard, users can better select different grades of fire-resistant and environmentally friendly cables to meet different requirements. Generally speaking, cable sheaths on the market are mainly divided into three types: ordinary (PVC); low-smoke halogen-free (LSZH/LS0H); and fire-resistant.
Firstly, regarding the use of raised floors or suspended ceilings on-site, if PVC cable trays are built-in and an air conditioning ventilation system is installed, we recommend users use flame-retardant (CMP or OFNP) structured cabling. For those with built-in metal cable trays/conduits or fire-resistant PVC cable trays/conduits, we suggest users use structured cabling of any fire resistance rating (CM//CMR/CMP or OFN/OFNR/OFNP).
Structured cabling of grades such as LSZH is suitable for densely populated areas, such as train stations, subways, airports, hospitals, or convention centers. Because these locations naturally have the highest requirements for environmental protection and fire prevention, after selecting the highest grade structured cabling, we also recommend that users use fire-resistant metal cable trays/conduits or flame-retardant PVC cable trays/conduits.
II. What are the differences between cables in a structured cabling system?
The difference between SYV and SYWV: SYV is a video transmission line, insulated with polyethylene. SYWV is a radio frequency transmission line, with physical foam insulation. It is used for cable television.
The difference between RVS and RVV2 cores: RVS is made of two stranded RV wires without an outer sheath and is used for broadcast connections. RVV2 cores are laid straight into a cable, have an outer sheath, and are used for power supply, control signals, etc.
The difference between RVV and KVVR/RVVP and KVVP: RVV and RVVP use soft wire composed of multiple strands of fine copper wire, i.e., RV wire. KVV and KVVP use hard wire composed of a single strand of thick copper wire, i.e., BV wire.
The difference between AVVR and RVVP: AVVR refers to unshielded cables with a wire diameter of less than 0.5 mm, while RVVP refers to shielded cables with a wire diameter of 0.5 mm or greater.
The difference between RVS and RVV2 cores: RVS is made of two stranded RV wires without an outer sheath and is used for broadcast connections. RVV2 cores are laid straight into a cable, have an outer sheath, and are used for power supply, control signals, etc.
That's all for today's discussion on cabling for structured cabling systems. Of course, when selecting cables for a structured cabling system, we can also choose based on the intended use. For example, video signal transmission generally uses direct modulation technology at baseband frequency (approximately 8MHz bandwidth), and the most commonly used transmission medium is coaxial cable. Coaxial cable is specifically designed for transmitting video signals, and its frequency loss, image distortion, and image attenuation are relatively small, making it well-suited for transmitting video signals.
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