What is a overhead service wire？
What is an overhead service wire?
Overhead insulated cable is a kind of overhead service line. It is composed of extruded inner shielding layer and weather-resistant cross-linked polyethylene or weather-resistant high-density polyethylene insulating layer outside the tightly pressed copper and aluminum conductors. Its structure is simple. , safe and reliable, at the same time has excellent mechanical and physical properties and electrical properties, excellent resistance to electric tracking and atmospheric resistance, compared with bare wires, the laying gap is small, saving limited line corridors, and reducing line voltage. General overhead insulated cables are single-core, due to different requirements for specifications and models in different places, overhead insulated cables can also be divided into two-phase overhead cables, three-core twisted overhead cables, and other types overhead service lines. Aerial insulated cables are used for laying in overhead power lines with a rated power frequency voltage of 35KV and below for power transmission and distribution. The allowable working temperature of the cable conductor is 90 degrees, and the maximum temperature of the cable is 250 degrees Celsius when short-circuited.
Duplex aluminum overhead cables have two conductors: one for the pole and the other for the messenger (neutral conductor). This wire, also known as duplex overhead aluminum wire, is designed and manufactured for use in 120 V distribution facilities. It is air mounted and has a maximum operating temperature rating of 75°C.
Triplex overhead service drop cable has three conductors, one for the neutral path, and two poles. Aluminum triplex cable is a type of cable used to run from utility lines through weather to distribution points at consumer premises. It is rated for a working voltage of 600 V and a maximum temperature rating of 75°C. This bare messenger wire cable is tightly bonded to two insulated aluminum conductors that are individually insulated with black XLPE for protection.
How to choose overhead insulated cables?
There are many types of wires on the market, and the appropriate wire should be used according to your own power load. Don’t choose cheaper cables because the performance of cheap wires may not meet the standards of the corresponding specifications, which will bring certain safety hazards. Here are a few ways to choose:
1. Wire surface mark
According to the national standard, the surface of the overhead service wire should have a continuous mark of the manufacturer's name, product model and rated voltage. This is conducive to finding the manufacturer in time when a problem occurs during the use of the wire. Consumers must pay attention to this when purchasing wires.
At the same time, consumers should pay attention to whether the manufacturer's name, product model, and rated voltage indicated on the certificate of conformity are consistent with the printed marks on the surface of the wire when purchasing wires, so as to prevent counterfeit products.
2. Appearance of the wire
When purchasing wires, consumers should pay attention to the appearance of the wires should be smooth and flat, the insulation and sheath layers should not be damaged, the logos should be printed clearly, and there should be no greasy feeling when touching the wires. From the perspective of the cross section of the wire, the thickness of the insulation or sheath on the entire circumference of the wire should be uniform, and the core should not be eccentric, and the insulation or sheath should have a certain thickness.
3. Conductor wire diameter
When purchasing wires, consumers should pay attention to whether the abc cable diameter of the conductor is consistent with the cross-section indicated on the certificate of conformity. If the cross-section of the conductor is too small, it is easy to cause the wire to heat up and cause a short circuit. It is recommended that wires for household lighting lines use 1.5 square millimeters and above; household appliances with large power such as air conditioners and microwave ovens should use wires with a size of 2.5 square millimeters and above.
4. Standard use
The wiring should be standardized, and it is best to use BV single-core wires to pass through the pipes for fixed lines. Be careful not to damage the wires when wiring, and do not damage the wires when decorating the room; do not connect the middle of a line; the wires are connected to the electrical box (box) Do not touch the line.