1. Fire-resistant cable

According to the national experimental standard (gb12666-99), fire-resistant cables can be divided into two grades: NHA and NHB;In general product naming, NHA is usually GNH, is a high fire resistance cable.NHB is expressed as NH in general refractory products.

Fire resistance refers to the situation of flame combustion can maintain a certain time of operation, that is, to maintain the integrity of the circuit, this type of cable in the flame has a certain time of power supply capacity.

Fireproof cables are actually another type of fireproof cable.It is made of copper as conductive core, seamless copper tube as sheath and inorganic mineral magnesium oxide as insulating material.

As the whole is composed of inorganic materials, therefore, the whole fire cable neither combustion, nor delay combustion.And can withstand fire.Experiments show that the flame burning in the 800 ~ 900 ℃ for 2 hours, have been normal the power cable, 30 minutes under 1000 ℃ flame combustion is still intact, continue to work normally.Normal working temperature is 250 ℃, safe and reliable operation.

Fire resistant cable can continue to work in the event of fire (transmission current and signal), the delay of its own combustion is not included in the assessment.Flame retardant cable in the event of fire will soon stop working, its function is difficult to burn and do not spread out can self-extinguish.Fire-resistance cable in 750 ~ 800 ℃ flame to maintain normal operation of 180 minutes

Two, flame retardant cable

Flame retardant cables can be divided into three grades according to the national experimental standard (gb12666-99) : ZRA, ZRB and ZRC.In general product naming, ZRA is usually represented by GZR, which belongs to the category of high flame retardant cable or oxygen insulation layer cable or high flame retardant oxygen insulation layer cable.ZRC stands for ZR in general flame retardant products.

Flame retardant refers to the retardation, delay the spread of flame along the wire and cable, so that the fire does not expand, this type of cable fire with self-extinguishing ability.

Flame retardant technology of oxygen insulation layer is mainly to fill a layer of inorganic metal hydride between cable insulated core and cable outer sheath.Flame retardant cables with oxygen insulation layer can be applied to low, medium and high voltage power cables, control cables and communication cables without changing the cable structure and raw material parameters, and make the cables flame retardant class A.

Halogen-free flame retardant cable has the advantages of low toxicity, low smoke and halogen-free compared with halogen-free flame retardant cable.Flame retardant level is not high, basically class C.The reason is that the energy efficiency of halogen free radical is higher than that of non-halogen flame retardant.

Flame retardant cable is to maintain the electrical and physical and chemical properties of ordinary cable, with self-extinguishing, that is, not easy to burn, or when the cable is on fire or external fire source ignition fire, after the fire extinguishing cable will not continue to burn, or combustion time is very short (less than 60 minutes), or the length of extended burning is very short.