The average person is easy to confuse the concept of flame-retardant cable and fire-resistant cable, although flame-retardant cable has many advantages more suitable for chemical enterprises, such as low halogen, low smoke flame retardant, etc., but in general, fire-resistant cable can replace flame-retardant cable, and flame-retardant cable can not replace fire-resistant cable. The main differences between them are:



1, the difference in principle

The principle of fire-resistant cable is different from that of flame-retardant cable. The flame retardant principle of halogen containing cable is based on the flame retardant effect of halogen, and the flame retardant principle of halogen free cable is based on the precipitation of water to reduce the temperature to extinguish the fire. The fire-resistant cable relies on the fire-resistant and heat-resistant characteristics of the mica material in the fire-resistant layer to ensure that the cable works normally in a fire.

2, the difference between structure and material

The structure and materials of fire-resistant cables are also different from those of flame-retardant cables.

The basic structure of the flame-retardant cable is: the insulation layer is made of flame-retardant materials, the sheath and the outer sheath are made of flame-retardant materials, the tape and the filling are made of flame-retardant materials.

The fire-resistant cable is usually between the conductor and the insulation layer and add a fire-resistant layer, so in theory, you can add a fire-resistant layer to the structure of the fire-retardant cable, forming a flame-retardant and fire-resistant cable, but in practice, there is no need.

Because of the refractory layer of fire-resistant cables, multiple layers of mica tape are usually used to wrap directly on the wire. It can withstand long-term combustion, even if the polymer where the flame is applied is burned, it can ensure the normal operation of the line.

Differences between video cables and RF cables

Video coaxial cable is also known as video cable or video surveillance cable, because it is mainly used to transmit image signals of a cable, mostly used to connect security surveillance cameras and realistic terminals (computers or monitors, etc.) wire and cable.

Radio frequency cable, also called coaxial cable, is composed of an inner conductor, an outer conductor and a medium that supports the inner and outer conductors. In radio communication, radio and television radio frequency transmission, radio frequency cable is an important backup.

Similarities:

1. The characteristic impedance is 75 ohms;

2. The outer sheath, shielding layer structure, outer diameter of insulation layer, selection of number of braid, selection of material, and number of shielding layers are basically the same;

The difference:

1. Insulation layer physical characteristics are different: SYV is polyethylene filled, dielectric constant ε=2.2-2.4; SYWV is also polyethylene filled, but filled with 80% nitrogen bubbles, polyethylene contains only 20%.

2. Core wire diameter is different: Take 75-5 as an example, because the -5 cable structure national standard stipulates that the outer diameter of the insulation layer is 4.8mm, which cannot be changed, in order to ensure the characteristic impedance of 75Ω, and the characteristic impedance is only related to the diameter ratio of the internal and external conductors and the dielectric constant ε of the insulation layer, ε large core wire is thin, ε small core wire is thick; Core wire diameter: SYV is 0.75-0.8mm,SYWV is 1.0mm; (The core structure can be single or multiple strands); This difference leads to the difference in core resistance.

3. The above two fundamental differences determine the transmission characteristics of the two types of cable transmission attenuation is different, SYV cable is an early coaxial cable, has been used for decades to transmit, including the transmission of radio frequency signals; But later, when SYWV appeared, it was rarely used in bands above radio frequency. Because the high frequency attenuation is so different; Slowly SYV is basically used in surveillance video transmission, people also put this radio frequency cable "elder", commonly known as "video cable".

Qingdao Tianxing Cable Co., Ltd. focuses on the production of customized wire and cable manufacturers, main: fire wire and cable, power cable, control cable and other products, exported to more than 40 countries and regions around the world, the annual production capacity of 1 billion yuan. 6000 square meters of storage, standing hundreds of millions of inventory, order demand for rapid distribution and delivery, large prices more favorable. Hotline: 16678668098