As an essential component of building electrical power, wires and cables have a wide range of applications. With the increasing electrical load in buildings, electrical fires caused by cable combustion are becoming more common. Furthermore, in the event of a fire, the safe and reliable operation of firefighting equipment requires the protection of wires and cables. Therefore, flame-retardant cables are frequently used in daily life.
What are WDZ-YJY cables?
I. Meaning
WDZ: Low-smoke, halogen-free, flame-retardant power cable.
WDZN: Low-smoke, flame-retardant, fire-resistant, flame-retardant, cross-linked power cable.
W = Halogen-free, D = Smoke-free, Z = Flame-retardant, N = Fire-resistant, YJ = Cross-linked polyethylene insulation, V = Polyethylene sheath, YJV = Cross-linked polyethylene insulation, polyethylene sheathed power cable.
Principle of Omission in Model Numbers: Copper is the primary conductor material in wire and cable products, so the copper core code T is omitted, except for bare wire and bare conductor products. Bare wire and conductor products, power cables, and magnet wire products are not listed with a major code. Electrical equipment and communication cables are also not listed, but subcategories or series codes are listed.
II. Product Introduction
Low-smoke, halogen-free, flame-retardant cables are suitable for transmitting power in power lines with a rated voltage of 0.6/1 kV and below.
III. Description of Low-smoke, halogen-free, flame-retardant cables
Low-smoke, halogen-free, flame-retardant cables are difficult to ignite and have the ability to prevent or prevent the spread of fire. Furthermore, if a fire ignites, they are halogen-free, low-smoke, non-toxic, and non-corrosive. They are suitable for applications such as high-rise buildings, hotels, hospitals, subways, nuclear power plants, tunnels, power plants, mines, the petroleum industry, and the chemical industry.
Low-smoke, halogen-free, fire-resistant cables not only meet the characteristics of low-smoke, halogen-free, flame-retardant cables but also provide adequate power supply capability under fire conditions. They are primarily used in power supply lines for fire alarms, firefighting equipment, smoke exhaust systems, and emergency transportation, lighting, and other emergency facilities where fire resistance is required.
(1) Flame retardant grade of low smoke halogen-free cable
According to the test conditions specified in GB/T18380.3-2002, the flame retardant grade of low smoke halogen-free cable is divided into four grades: A, B, C, and D.
(2) The insulation of low smoke halogen-free cable adopts halogen-free cross-linked polyethylene, and the sheath adopts halogen-free polyolefin material, so all the materials that make up the cable are halogen-free. The amount of smoke released when the cable burns is very small. It does not produce thick acid mist or toxic gas, and its toxicity is very low.
What are the characteristics of WDZ-YJY cable?
1. Low smoke halogen-free flame retardant type
1) The flame retardant performance should be able to pass the bundled cable burning test of GB18380. After the test, the height of the burnt or affected part of the cable should not exceed 2.5m above the flame action point, or a single vertical burning test.
2) The halogen acid gas release test must meet the requirements of GB/T17650.1-1998, Determination of Total Halogen Acid Gas (5 mg/g), and GB/T17650.2-1998, Determination of Gas Acidity by pH and Conductivity (4.3 in 1 L of water; the conductivity value should not exceed 10 μs/mm).
3) The smoke density test must meet the requirements of GB/T17651.2-1998, Determination of Smoke Density of Cables or Optical Fibers Burning under Typical Conditions (minimum transmittance 60%).
4) The DC resistance of the conductor must comply with the requirements of GB/T3956.
5) Power frequency withstand voltage test: Power cables must withstand 3500V for 5 minutes without breakdown. Control cables must withstand 3000V for 5 minutes without breakdown.
6) The specimen must withstand a -15°C low-temperature winding test or a low-temperature impact test. After the test, no visible cracks should be observed on the surface of the specimen.
2. Low-Smoke, Halogen-Free, and Fire-Resistant Type
In addition to meeting the flame-retardant, low-smoke, and halogen-free performance requirements, it must also pass the fire resistance test specified in GB/T19216-2003, "Line Integrity Tests for Cables or Optical Fibers Under Flame Conditions," requiring a 2A fuse to burn at 750°C for 90 minutes without breaking.
The above is a brief introduction to WDZ-YJY cables. I believe you have already understood their characteristics. The selection of wires and cables for building electrical systems not only affects the proper operation of electrical equipment and the cost of building electrical projects, but more importantly, it impacts the safety of electrical equipment and even the personal safety of building occupants.
