1. What are the tips for purchasing wires and cables?
The tips for purchasing wires and cables are as follows: Rubber and sheath: smooth and round, uniform in color, insulating rubber and copper core close together It is not easy to peel off. The low-quality rubber looks thick, but when squeezed hard, the squeezed area will turn white, and it will easily fall off in the future, causing leakage. For weak current sheaths, regular "unevenness" can be seen on the surface of the compressed mesh inside. There will be no relative sliding.
Eccentricity: The thickness of the rubber ring is consistent, that is, if the copper core is in the middle of the wire, the eccentricity will be low; Insulation layer: Cut the insulation layer diagonally and peel off the insulation layer to see if there is any larger The adhesion force (poor cable does not adhere); Flame retardant: Use a lighter to burn the rubber. When the lighter leaves the wire, the wire should automatically extinguish and release a small amount of white smoke. If the flame spreads and a large amount of white smoke is released, the quality of the rubber is poor; Copper core: You can use a magnet to detect whether it is doped with iron, or rub a piece of white paper on the copper core. If there is black matter on the white paper, it means there are more impurities in the copper core. The tighter the copper core of weak current cables is, the better; Thickness: The size of inferior copper cores is often smaller than that of regular manufacturers, and the outer insulation is thick, and the wire cross-section diameter error should not exceed 0.
02%; Length: The length of a coil of wire conforms to the national standard 100±0.5m (that is, based on 100 meters, the allowable error is 0.
5 meters); Weight: Whole Coiled wire (100 meters), 1. 5 square meters cannot be less than 1871 grams, 2.
5 square meters shall not be less than 2915 grams, 4 square meters shall not be less than 4312 grams, and 6 square millimeters shall not be less than 6107 grams.
2. How to choose wires
Look at the logo.
Check whether there is the "Great Wall Mark" and the production license number of the China Electrical Products Certification Commission on the package of rolled wires; check whether the outer plastic skin of the wire is bright in color and fine in texture, and light it with a lighter. There should be no open flames. Irregular products use recycled plastic, which is dull in color and loose in texture and can ignite open flames.
Look at the length and compare the price. Such as BVV2X2.
5 The length of each roll is 100±5 meters, and the market price is about 280 yuan; the length of informal products ranges from 60 to 80 meters. Some manufacturers make the insulation outer skin thicker, so that insiders can It’s also hard to see the problem. However, you can count the number of turns of the wire and then multiply it by the radius of the entire roll to roughly calculate the length. The price of this type of product is between 100 and 130 yuan. Secondly, you can ask the merchant to cut a broken end to see if it is copper. Core material.
2X2. 5 copper core diameter is 1.
784 mm, you can use a micrometer to measure it. Regular product wires use fine red copper, and the outer layer is bright and slightly soft.
The copper of informal products is black and hard, which is recycled miscellaneous copper. It has high resistivity, poor conductivity, heats up and is unsafe. Among them, BVV is the national standard code, which is copper sheathed wire, 2X2.
5 represents 2 cores 2. 5mm2; 4X2.
5 represents 4 cores 2. 5 square millimeters.
Look at the appearance. When purchasing wires, you should pay attention to the appearance of the wires, which should be smooth and flat, with no damage to the insulation and sheath layers, clear markings, and no greasy feeling when touching the wires.
Look at the cross section. When purchasing wires, owners should pay attention to whether the conductor diameter matches the cross-section indicated on the certificate. If the conductor cross-section is too small, it is easy for the wire to heat up and cause a short circuit.
It is recommended that wires for home lighting circuits should use wires of 1.5 square millimeters and above; household appliances with larger power such as air conditioners and microwave ovens should use wires of 4 square millimeters and above.
3. What are the tips for purchasing wires for home decoration?
1. Wire purchasing channels Users who are not very price sensitive can go to regular shopping malls to buy wires. After all, they can come into contact with the real thing. Be intuitive and look for the trademarks, specifications, voltages, etc. printed on the wires to prevent errors.
If you want to buy cost-effective wires, you can only choose online shopping channels. Some brands have also opened brand flagship stores on Taobao, which are officially directly operated. You can rest assured that the biggest advantage is the price ratio. Offline shopping malls are much cheaper because they don’t have to pay for venue rent, sanitation fees, and price increases from agents.
2. Wire types The two most important wire types in home decoration wires are BV and BVR wires. Currently, BV wires are used more widely than BVR wires in home decoration.
In terms of softness and hardness, BV wire is harder than BVR wire, and the inner core is 99.99% oxygen-free copper.
BV: Advantages: Long service life, not easy to oxidize due to small outer circle area/cross-sectional area ratio, and resistant to short-circuit current impact. It is generally used in shielding projects; in some places with strict requirements, such as the secondary lead wire of current transformer, the regulations clearly indicate that the use of BVR wire is prohibited.
Disadvantages: The wire is hard and difficult to straighten after bending. It is easy to be injured after repeated bending and straightening. It is labor-intensive when casing small tubes. It is mostly used in fixed and buried environments.
BVR: Advantages: Because the wire is relatively soft, it is mostly used in active and temporary power consumption places. It is easy to install, drag and drop, and move. Disadvantages: short service life, due to the large outer circle area/cross-sectional area ratio and fast oxidation rate. If affected by short-circuit current, the surface will be severely oxidized after high temperature, the effective cross-section will be greatly reduced, and problems such as core breakage and local heating will easily occur. It should be replaced in time for safe use of electricity.
3. Flame-retardant wires In recent years, flame-retardant wires with higher safety factors have become the first choice of many users. Flame-retardant BV is an upgrade of ordinary BV and is a safety technology revolution. Therefore, the process and raw materials The requirements are higher, so the cost is higher. Generally, the price on the market is about 10% higher than that of ordinary BV. Many brands are unable to produce flame-retardant BV due to lack of technical strength. Flame-retardant BV can withstand high temperatures of up to 1,000 degrees. However, ordinary BV will already burn at 200-300 degrees, posing a safety hazard. The main reason why flame-retardant BV has a high ignition point is that the outer sheath is made of flame-retardant plastic and there are flame-retardant components inside.
At high temperatures, this flame retardant sheath will not burn, it will only melt. Therefore, it will not burn directly like ordinary BV, and the safety factor will be much greater.
For long-term safety, it is recommended that you use flame-retardant BV wires! 4. Precautions when purchasing wires: The length of a bundle of wires is 100 meters, with a plus or minus error of 0. 5 meters, some businesses also provide zero-cut wires. This short-segment wire meets the needs of some users to purchase wires in small quantities.
Commonly used specifications are 1 square meter/1. 5 square meters/2.
5 square meters/4 square meters/6 square meters/10 square meters, etc.; Generally used for sockets are single core wire bv2. 5 square wires; 3 air conditioners and above use single core wire bv4 square wires, according to different colors It is a set of 3 rolls (used for neutral wire, live wire, and ground wire); the single-core wire bv1 is used for lamp lighting.
5 square wires, two rolls in sets of different colors (used for neutral and live wires); single-core bv6 square wires are used for home bus lines; live wires are generally yellow, green, red, and neutral wires It is blue, and the ground wire can be yellow and green. Two-core and three-core sheathed wires are used as open wires. They are mostly used for construction on construction sites and are rarely used in home decoration. Three-core sheathed wires are available in 2.5 square meters. on cabinet air conditioners.
4. How to choose wires
The purchasing method is as follows: 1. The cassette to install the switch should be of good quality. 2. The lighting wire is 1.5, the socket wire is 2.5, and the air conditioner Use 4 lines.
Panda wire is recommended. Use a 2.5 socket cord for the bathroom heater. If possible, 4 would be the best.
3. The quality of the threading pipe must be good. Place it on the ground and step on it. At least it cannot be easily broken. The threading pipe should be flame-retardant PVC pipe. The surface of the pipe wall should be smooth and the wall thickness should be as required. It must be strong enough to be pinched with fingers and cannot be broken, and it must have a certificate of qualification. You can also use national standard special galvanized pipes as threading pipes.
Nowadays, PVC pipes generally come in two types: 6 points and 4 points. If conditions permit, use 6 points.
A 4-point pipe can only pass 1.5 lighting wires, and only a maximum of 3 wires can be passed through a pipe. A 6-point pipe can be threaded with 2.5 wires, but a maximum of 3 2.5 wires can be threaded in one tube.
In addition, joints must be used when connecting PVC pipes, and glue must be used to connect them firmly. Moreover, the connection between the PVC pipe and the wire box must be covered with a special cover, and the PVC pipe and the wire box must not be directly connected.
5. What should you pay attention to when purchasing household wires?
When purchasing household wires, you must purchase wires that meet national standards.
First of all, we need to check whether there is a quality system certificate and whether the certificate is standardized. Secondly, look at the production date and inspection stamp, and whether there are trademarks, specifications, voltage, etc.
Then take a wire end and bend it repeatedly. If it feels soft to the touch, has high elasticity and has no cracks in the insulator. Generally, the weight of good quality wires is specified within a certain range.
Plastic insulated single-strand copper core wire with a cross-sectional area of ??1.5 mm2 weighs 1.8~1.9 kg per 100 m. 5 mm2 plastic insulated single-strand copper core wire weighs 3~3.1 kg per 100 m, etc.
Finally, check whether the copper core battery is purple-red in color, shiny and soft to the touch. Inferior quality generally has poorer toughness.
6. Are there any tips for purchasing wires and cables?
1. Look at the appearance: The insulation (sheath) layer of qualified products is soft, tough and stretchable, and the surface layer is tight and Smooth, no roughness, and has a pure gloss.
2. The surface of the insulation (sheath) layer should have clear and scratch-resistant markings. For products produced from informal insulation materials, the insulation layer feels transparent, brittle, and has no toughness.
3. Look at the insulation layer: National standards have clear data regulations on the thinnest point and average thickness of the wire insulation layer. The insulation layer of regular wires has a uniform thickness, is not biased towards the core, and is tightly packed around the conductor.
4. Look at the certificate: The standard product certificate should indicate the name of the manufacturer, address, after-sales service telephone number, model, specification structure, and nominal cross-section (that is, usually 2.5 square meters, 4 square wires, etc.), rated voltage (single-core wire 450/750V, two-core protective sheathed wire 300/500V), length (the national standard stipulates that the length is 100M±0.
5M), inspection employee number, Manufacturing date and national standard number or certification mark of the product. 5. Look at the specifications: It is particularly pointed out that the model number of the single-core copper core plastic wire marked on regular products is 227IEC01 (BV), not BV. Please pay attention to the identification.
6. Look at the wire core: The wire core is produced from pure copper raw materials and has been strictly drawn, annealed (softened) and twisted. Its surface should be bright, smooth, without burrs, tightly twisted and flat, soft and tough, and not easy to break.