Electric cables for households– A comprehensive guide

Depending on the number of devices and needs, a home electrical network can range from simple to complex structures. Some basic components include:

• Main circuit: This is the main power line coming from the electricity meter into the house, responsible for distributing electricity to branch circuits. It's the most critical part of the system, protected by devices like automatic circuit breakers to ensure safety.
• Branch circuits: These lines branch off from the main circuit, designed in parallel to independently supply electricity to specific areas or devices. They optimize electricity usage, allowing devices in different rooms to operate simultaneously without overloading the system.
• Protective devices: Components like MCB circuit breakers and RCDs prevent overloads, short circuits, or electrical leakage.
• Electricity meter: A device measuring household electricity consumption, acting as the connection point between the national grid and the home electrical network.
• Electrical appliances: End devices like sockets, switches, lighting fixtures, and household appliances that directly serve the user's needs.

A household electrical network distributes power to devices while ensuring stable and safe operation. Key characteristics include:

• Voltage and current: In Vietnam, household electrical systems operate at 220V, adhering to IEC standards, with rated current ranging from 15A to 20A depending on device power consumption.
• Branch structure: A branched design simplifies maintenance and ensures uninterrupted electricity supply when issues occur in one branch.
• Protection devices and grounding: Proper grounding safeguards users against electric shocks.
• Energy efficiency: The system should be optimized to minimize energy loss. High-quality cables with appropriate cross-sections are crucial.
• Smart home integration: Modern homes often integrate smart electrical systems for remote device control and energy-saving automation, requiring specialized cables for lighting, security, control systems, and fire alarms.

3.3 Three-phase four-wire system

This system is a suitable choice for households or small production facilities operating heavy machinery, such as grinders, cutting machines, or equipment requiring stable current. Its structure consists of three phase wires and one neutral wire, providing 380V voltage between the phases or 220V voltage between a phase and the neutral wire, ensuring high performance during operation.

3.4 Three-phase five-wire system

This is an advanced electrical system, less commonly used in residential buildings unless in special cases such as industrial devices or machinery with strict safety requirements. It includes three phase wires, one neutral wire, and one protective grounding wire. This configuration ensures maximum user safety by eliminating leakage current and minimizing the risk of electrical accidents. Although highly safe and efficient, the installation and operation costs of this system are high, making it more suitable for industrial projects or factories.

To determine the appropriate type of cables for household electrical systems, users should consider the following factors:

4.1 Identify the power source

Users need to identify the type of power source used in the household, such as single-phase or three-phase power. This depends on the household's energy requirements and the local power supply. Some households also combine solar energy with the national grid to optimize costs and minimize energy consumption. Determining the type of power source helps in selecting the right cables and designing a system that meets the home's electrical load requirements.

4.2 Determine the total power consumption

One of the most important principles in household electrical wiring is calculating the total power consumption of all electrical devices in the house. From lighting, fans, and TVs to high-power appliances like air conditioners, ovens, and water heaters, each device has a specific power consumption rating. Check the power rating indicated on each device and add them up to determine the total power requirement for each area in the house. Based on this calculation, you can select wires with appropriate cross-sectional areas to ensure efficient operation of the system without overloading it.

4.3 Select appropriate cables for each part of the system

Electrical cables should be chosen based on the branches of the electrical circuit and the characteristics of each area in the house. Key considerations when selecting cables for home electrical systems include:

• Cable cross-section: Choose cables with a cross-sectional area suitable for the load capacity. Undersized cables can overheat and cause short circuits or fires.
• Cable characteristics: For high-temperature areas like kitchens or outdoor spaces, select cables with good heat resistance. In areas with high humidity, such as bathrooms, choose cables with moisture- and water-resistant attributes.