Fireproof wire and cable refers to the general term for wire and cable with fireproof performance. It is usually divided into two types: flame retardant wire and cable and fire resistant wire and cable.
1, flame retardant wire and cable
Flame retardant refers to retarding and delaying the spread of flame along the wire and cable, so that the fire does not expand. This type of cable has self-extinguishing performance after ignition.
Flame-retardant cables can be divided into three grades according to national experimental standards (GB12666-99): ZRA, ZRB, ZRC. In the general product naming, ZRA is usually expressed by GZR, which is called high flame-retardant cable or oxygen barrier cable or high flame-retardant oxygen barrier cable. ZRC represents ZR in general flame retardant products.
The flame-retardant cable is self-extinguishing, that is, it is not easy to burn, or when the cable is ignited by fire or the external fire source ignites the fire, the cable does not continue after the fire is extinguished. Burning, or burning time is very short (within 60 minutes), or the length of the flame retarding is very short.
The flame-retardant technology of the oxygen barrier layer is mainly filled with an inorganic metal hydrate between the cable insulated core and the outer sheath of the cable, which is a non-toxic, odorless, halogen-free white gel. The oxygen barrier flame retardant cable 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 makes the cable flame retardant Class A.
2, fire resistant wire and cable
Refractory refers to the operation that can be maintained for a certain period of time in the case of flame combustion, that is, to maintain the integrity of the circuit. This type of cable has a certain power supply capability in the flame.
Fire-resistant cables can be divided into two grades according to national experimental standards (GB12666-99): NHA, NHB; in general product naming, NHA is usually expressed by GNH, which is called high-resistance cable. NHB is indicated as NH in a general refractory product.
Fire-resistant cables can continue to work in the event of a fire (transmission of current and signals), and their own flame retardation is not included in the assessment. The flame-retardant cable stops working quickly in the event of a fire, and its function is that it is difficult to burn and self-extinguish. The fire-resistant cable is maintained at 750-800 ° C for 180 minutes in normal operation.
A fire resistant cable is actually another type of fire resistant cable. It is made of copper as the conductive core, with a seamless copper tube as the sheath and inorganic mineral magnesium oxide as the insulation material.
Since the whole is made of inorganic materials, the entire fireproof cable neither burns nor ignites. And can withstand fire. Tests have shown that: the cable is burned for 2 hours in the flame at 800-900 ° C, the cable has been running normally, and it is still intact under the flame of 1000 ° C for 30 minutes, and continues to operate normally. The normal working temperature is 250 °C, which can operate safely and reliably.