Basic Knowledge of Cables and Wires and Main Methods of Laying Cables

Basic Knowledge of Cables and Wires and Main Methods of Laying Cables

Understanding cables and wires, their types, uses, and installation methods is crucial for efficient and safe electrical work. This article provides comprehensive insights into these aspects.

Basic Knowledge of Cables and Wires

Cables and wires come in various types and are used for different purposes. The common symbols and abbreviations in cable identification help in recognizing and selecting the right cable for specific applications.

1. Common Symbols and Their Meanings:

• B: Electrical wire (sometimes not indicated)

• T: Copper core (default representation)

• L: Aluminum core

• R: Soft copper

• V: Polyvinyl chloride insulation

• X: Rubber insulation

• F: Neoprene rubber

• P: Shielding

• B: Parallel

  
  

2. Examples of Common Wires:

• BX, BLX: Rubber insulated wires, used for fixed installations indoors.

• BXF, BLXF: Neoprene rubber insulated wires, suitable for outdoor use.

• BXR: Rubber insulated soft wires, used in installations requiring flexibility.

• BV, BLV: Polyvinyl chloride insulated wires, better for damp and weather-exposed environments.

• RV: Single-core copper core polyvinyl chloride insulated flexible wire, used for connecting various mobile appliances, instruments, and telecommunication devices.

1. Specification Indication Methods:

• Example: RVVP 2×32/0.2 means soft wire with double sheath and shielding, 2 cores with 32 strands of 0.2mm diameter copper wire each.

2. General Wire Specifications:

• Voltage Rating: 300/500V, 450/750V

• Wire Sizes: 1.5, 2.5, 4, 6, 10, 16, 25, 32, 50, 70, 95, 120, 150, 185, 240, 300, 400.

Methods of Laying Cables

Laying cables involves several methods, each suitable for different environments and requirements. Proper laying ensures the safety, efficiency, and longevity of the cables.

1. Open Laying:

• Description: Cables are laid openly on walls, ceilings, or poles, visible and accessible for maintenance.

• Applications: Used in industrial and commercial buildings where aesthetics are less important.

• Advantages: Easy to install and maintain.

1. Concealed Laying:

• Description: Cables are hidden within walls, floors, or ceilings.

• Applications: Residential buildings and offices where aesthetics are important.

• Advantages: Protects cables from mechanical damage and improves aesthetics.

2. Underground Laying:

• Description: Cables are buried underground in trenches.

• Applications: Outdoor and long-distance cable runs, such as between buildings or across fields.

• Advantages: Protects cables from weather and physical damage.

3. Cable Support and Fixing Methods:

• Clamp Boards: Used for fixing cables on walls and ceilings.

• Porcelain Bottles: Provide insulation and support for overhead cables.

• Wire Ducts: Enclosed channels for organizing and protecting cables.

1. Additional Laying Methods:

• Clipboard Wiring: Using porcelain or plastic clipboards to hold and fix wires.

• Porcelain Bottle Wiring: Using porcelain bottles to support and fix wires, suitable for large cross-sectional areas and damp environments.

• Slot Wiring: Using plastic or metal slots to support and fix wires in dry environments.

• Clamp Nail Sheath Wiring: Using plastic clamps to support and fix wires in dry environments.

• Steel Cable Wiring: Suspending wires on steel cables for large-span areas like large spaces and lighting.

2. Conduit Wiring:

• Description: Wires are placed inside conduits which are then laid openly or concealed within buildings.

• Applications: Used in various environments based on conduit material, primarily for concealed installations.