What is PVC wire and cable?
What is PVC wire and cable?
PVC cable is based on polyvinyl chloride resin, adding stabilizers and other materials mixed and extruded into insulation materials required for wire and cable. The wires and cables made of polyvinyl chloride cables are called polyvinyl chloride wires and cables, which have good flame retardancy, and the gas released in case of fire will not cause serious secondary damage to the human body.
一、What are the requirements for environmental protection of PVC wire and cable?
1. Requires low content of lead and heavy metals
It is well known that lead and some heavy metals will have adverse effects on human health, and in PVC formulations, it is usually necessary to mix additives of heavy metal compounds such as lead, cadmium, and barium. Since the 1990s, some developed countries and large electric companies have successively formulated regulations, and the content of eight heavy metals in the PVC wires and cables used should not exceed the regulations. While these new normative systems bring new business opportunities to manufacturers, they also bring certain challenges.
2. It is required to have low smoke and low hydrogen oxide
The biggest advantage of PVC wire and cable is its superior flame retardant performance. However, when ordinary flame retardant PVC cables are on fire, they will release thick black smoke and a large amount of HCI gas, which will cause "secondary disasters" after the fire. ", directly and seriously affect the work of fire rescue personnel and the rapid evacuation of personnel. Therefore, while the flame retardant requirements are put forward for wires and cables, the requirements for "low smoke" and "low HCI" will be further put forward in some use occasions.
3. Low toxicity or non-toxicity is required
Cables used in some household appliances, medical appliances and electric toys for children that may come into contact with food and blood products are required to be non-toxic (or low-toxic) in addition to lead-free and heavy metal-free. This means that all ingredient materials used in PVC formulations should be non-toxic. Cable materials contain a large amount of plasticizers, but non-toxic plasticizers must be selected for the manufacture of non-toxic materials. Therefore, the requirements of this PVC material are higher than those of lead-free and heavy metal-free materials, and the price is naturally more expensive.
4. Other prohibited items
At present, the regulations under review by the European Union restrict the following items to ensure that wires and cables can meet environmental protection requirements. For example: 1) asbestos; 2) mostly biphenyl and its ethers, polybrominated phenol; 3) polychlorinated biphenyl; 4) short chain (C10~C13) chlorinated paraffin.
二、Precautions for purchasing PVC wire and cable
1. Prefer regular manufacturers and merchant products. The wires packaged in reels should have a certificate of conformity, and the wire body should be printed with the factory name or trademark, voltage, 3C logo, etc.
2. The conductor materials used for wiring are mainly copper and aluminum. When we choose wires and cables, we should choose the corresponding specifications according to the load used. For example, the lighting circuit uses 1.5 square millimeter copper wire or 2.5 square millimeter aluminum wire, and the air conditioner, microwave oven, oven, etc. use 2.5 square millimeter copper wire or 4 square millimeter aluminum wire. Aluminum wires, choosing wires with appropriate specifications can avoid short-circuit fires caused by insufficient carrying capacity of small-sized wires; secondly, pay attention to the quality of conductors when purchasing, and qualified copper core wires should use purple-red, shiny, and soft copper materials. , while the copper core of fake and inferior copper core wires is purple-black, yellowish or white, with many impurities, poor mechanical strength, poor toughness, and will break with a little force, and if it is multi-strand copper wire, it often breaks. Short life.
3. The sheath used for the wiring is polyvinyl chloride insulating material. Qualified wire insulation has a smooth appearance and clear printing on the surface. The insulation of wires and cables should be evenly distributed and completely wrap the entire core. The insulation layer of some fake and inferior wires seems to be very thick, but in fact they are mostly made of recycled plastics. Over time, the insulation layer will age and cause electricity leakage.
4. Good quality wires are generally within the specified weight range. In terms of product prices, the production cost of fake and inferior products is low. Therefore, we must prevent being deceived when purchasing cables.