Power Wiring for Container Houses

The power wiring for container houses should be designed according to the type of distribution box, the nature of the electrical load, and safety regulations. The core steps include determining the wiring method, selecting an appropriate distribution box, installing it in a standardized manner, and ensuring grounding protection.

1. Determining the Wiring Method for the Distribution Box

The power supply for container houses typically combines power distribution and lighting distribution. The incoming power distribution lines are mostly five-wire systems, including three phase lines (A, B, C, colored yellow, green, and red), one neutral line (light blue), and one ground line (yellow-green striped). The outgoing lines are configured according to the load type:

• 220V Loads (such as lighting and sockets): One phase line, one neutral line, and one ground line are used to ensure single-phase electrical safety.
• 380V Loads (such as three-phase motors): All three phases are taken, and a ground line is added; if the load requires local control (such as a motor with a start button), a neutral line is also introduced.
• Special Equipment (such as two-phase 380V AC welders): Any two phase lines plus a ground line can be used, but it should be noted that some construction sites may omit the ground line, posing a safety hazard.

Lighting distribution can be simplified to one phase line + neutral line + ground line according to the load size, or directly use the 220V configuration of the power distribution.

2. Selecting and Installing the Distribution Box

• Type Selection: AC integrated distribution boxes are commonly used for container houses, and three-phase balance design should be considered to avoid power supply and consumption deviations. The box body should reserve independent power supply circuits for equipment such as air conditioners, fans, and lighting, and be equipped with overload and short-circuit protection devices (such as circuit breakers).
• Installation Method:
  • Surface Mounting: Fixed to the wall with expansion bolts. The bolt length should cover the embedding depth (75-150mm), the thickness of the box bottom plate, and the thickness of the nut and washer, with a 5mm protrusion allowance; small distribution boxes can also be fixed with pre-buried wooden bricks.
  • Flush Mounting: When building the wall, reserve holes that are 20mm larger in length and width than the box body, with a depth equal to the box body thickness plus the plaster layer thickness. The box body is fixed by filling concrete between the box and the wall.
• Installation Requirements: The distribution box should be level and vertical, with a vertical deviation of ≤3mm; for flush mounting, the panel should be tightly attached to the wall with no gaps around it, and the part of the box body in contact with the building should be painted with anti-corrosion paint.

3. Grounding and Safety Regulations

• Ground Line Connection: The ground line must be crimped to the grounding terminal block and must not be omitted (especially in construction site environments) to ensure personnel safety in case of equipment leakage.
• Neutral Line Handling: The neutral line is crimped to the neutral terminal block and should not be mixed with the ground line; in power distribution, the neutral line is only introduced when the load requires local control.
• Line Identification: Phase lines, neutral lines, and ground lines should be distinguished by standard colors to avoid incorrect connections; the connection terminals should be tightened to prevent loosening and causing fires.