The meaning of flame-retardant cable and the difference between zc, za and zb of flame-retardant cable

1、 What is the meaning of flame retardant wire?

The meaning of flame retardancy: under the specified test conditions, when the sample is burned, after the fire source is removed, the flame spread on the sample is only within the limited range and extinguishes itself, that is, it has the ability to prevent or delay the occurrence or spread of the flame.

The combustion of cables is caused by the flammable gas generated by external heating. To achieve the purpose of flame retardancy, the three elements that cause combustion must be suppressed, namely, combustible gas, heat and oxygen. Therefore, the generally adopted method for flame retardant wires and cables is to add halides and metal oxides containing halogens in the sheathing materials, which is an excellent method to evaluate from the perspective of flame retardancy. However, because these materials contain halogens, they release a lot of smoke and hydrogen halide gas during combustion, so the visibility in case of fire is low, which greatly hinders the safe evacuation of personnel and fire fighting, People are suffocated to death by toxic gases.

In addition, once the hydrogen halide gas reacts with the water in the air, it will generate "hydrogen halide acid", which will seriously corrode the instruments, equipment and buildings, causing "secondary disasters".

At present, with the continuous improvement of science and technology, the flame retardant problem has developed from halogen flame retardant in the past to low halogen and halogen-free flame retardant.

The representation method of wires and cables mainly consists of model, specification and standard number. 1. The meaning of model is that the models of chopped wire cables and power cables for electrical equipment are mainly composed of the following seven parts: some special wire and cable models have derivative codes at the end. The meanings of the letters in the most commonly used wire and cable models are introduced as follows: 1) Category and purpose code A - Installation line B - Insulated wire C - Marine cable K - Control cable N - Agricultural cable R - Flexible cable U - Mining cable Y - Mobile cable JK - Insulated overhead cable M - Coal mine ZR - Flame retardant NH - Fire retardant ZA-A flame retardant ZB-B flame retardant ZC-C flame retardant WD - Low smoke zero halogen type.

2、 What are the differences between cable models ZA, ZB and ZR?

ZR means flame-retardant. There are three levels of flame-retardant: A, B and C. ZB represents flame-retardant level B, and ZR defaults to flame-retardant level C.

Flame retardant characteristics ZA>ZB>ZC.

Flame retardant cable

3、 Flame retardant rubber sheathed cable

1. Purpose

This product is a series of rubber sheathed flexible cables for mining. It is suitable for power connection of shearers and similar equipment with rated voltage Uo/U of 1.9/3.3KV and below. It is mostly used in coal mines.

2. Conditions of Use

The long-term allowable working temperature of the wire core is 65 ℃, and the minimum bending radius of the wire is 6 times of the cable diameter. Yellow sheathed cables shall not be exposed to sunlight for a long time.

In the demanding electric power and electrician industry, the cables we use are also different from ordinary cables. They are often flame retardant and heat insulated cable products, and they will not have performance disorder after being baked at high temperature.