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 cables?

Flame-retardant cables refer to the characteristic that the cable is burned under the specified test conditions. After the fire source is removed, the flame spread on the cable is only within a limited range and extinguishes itself, that is, it has the ability to prevent or delay the occurrence or spread of flame.

The combustion of the cable is caused by external heating to produce flammable gas. To achieve the purpose of flame retardancy, the three elements that cause combustion must be suppressed, namely: flammable gas, heat and oxygen. Therefore, the method generally used for flame-retardant cables is to add halogen-containing halides and metal oxides to the sheath material. This is an excellent method to evaluate from the perspective of flame retardancy. However, because these materials contain halides When burning, it releases a large amount of smoke and hydrogen halide gas, so the visibility during fire is low, which greatly hinders the safe evacuation of personnel and fire fighting, and people are more likely to die from suffocation due to toxic gas.

In addition, once the hydrogen halide gas reacts with water in the air, "hydrohalide acid" is generated, which will severely corrode equipment and equipment and cause "secondary disasters" to buildings.

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

2. What is the difference between ZA, ZB and ZR of flame-retardant cables?

According to the category and purpose, the meanings of the letters in the wire and cable model are:

A-installation wire
B-insulated wire
C-ship cable
K-control cable
N-agricultural cable
R-soft wire
U-mining cable
Y-mobile cable
JK-overhead insulated cable
ZR-flame-retardant
NH-fire-resistant Type
ZA-A flame-retardant
ZB-B flame-retardant
ZC-C flame-retardant
WD-low smoke zero halogen cable

ZR means flame retardant. Flame retardant is divided into three levels: A, B, and C. ZB stands for B flame retardant, and ZR defaults to C flame retardant.

Flame retardant properties ZA >ZB >ZC.