Analysis of Problems and Measures for Power Distribution Cabinets in Building Electrical Installation
1. Problems with Power Distribution Cabinets in Building Electrical Installation
(1) Quality issues of the power distribution cabinets themselves.
Non-standard grounding of power distribution cabinets: Some cabinets lack dedicated grounding terminals or neutral bar terminals, which compromises structural integrity and safety, increasing the risk of short circuits, fires, and posing serious threats to the entire building electrical system.
Failure to reserve spare circuits according to industry standards and system design: This leaves the power distribution cabinets in a high-risk state, endangering the safety of both the cabinets and the building electrical system.
(2) Installation quality issues of power distribution cabinets.
These issues primarily lie in installation details, which can be identified through measurement and inspection. Common problems include:
Uneven installation of the cabinet body;
Non-compliant gaps between the cabinet and the wall;
Poor opening or closing of the cabinet door;
Improper pipe penetration at welding points;
Non-compliant openings that do not meet design and technical requirements;
Damage to the cabinet’s appearance during construction;
Damage to the paint layer due to welding;
Incorrect dimensions for cable entry into the cabinet;
Poor protection of pipe openings;
Lack of protective grounding for the cabinet.
These issues severely affect the installation speed and quality of power distribution cabinets and may even threaten the safety of the power network during operation, potentially leading to fires or system failures in the building electrical system.
(3) Wiring quality issues inside power distribution cabinets.
Common wiring problems include:
Incorrect repeated grounding and insufficient conductor cross-sections;
Exposed wire ends, disorganized wiring, splices inside the cabinet, insufficient wire slack, and multiple wires connected to a single terminal;
Confusion in the color coding of three-phase, neutral (N), and protective earth (PE) wires;
Lack of circuit identification or non-standard labeling.
These issues compromise the functional stability and operational safety of the power distribution cabinets.
2. Analysis of Causes of Common Quality Issues in Power Distribution Cabinet Installation
(1) Causes of power distribution cabinet quality issues.
In a market economy, some construction companies resort to using substandard cabinets to reduce costs and maximize profits. Additionally, collusion between design, supervision, and construction units leads to lax quality control, allowing the use of products. Unqualified installation teams, guided solely by cost-cutting directives, often select low-quality cabinets and components, further exacerbating quality risks.
(2) Causes of common installation quality issues.
These issues are widespread and often stem from:
Poor coordination between cabinet installation and civil engineering work, such as inaccurate pre-opening and embedding during the civil construction phase, resulting in deviations;
Failure to integrate cabinet installation with existing structures, prioritizing installation over future maintenance and usability;
Rough construction practices to save time, leading to inaccuracies in pipe entry positions, opening sizes, and quantities;
Lack of understanding of installation standards, resulting in improper grounding and poor contact at grounding points.
(3) Causes of common wiring quality issues inside cabinets.
These primarily arise from:
Insufficient understanding of repeated grounding and electrical protection principles;
Lack of responsibility and neglect of wiring craftsmanship during installation.
3. Handling and Prevention of Common Quality Issues in Power Distribution Cabinet Installation
(1) Handling and prevention of power distribution cabinet quality issues.
Emphasize cabinet quality during building electrical installation by selecting reliable products to prevent common issues at the source. Strictly inspect quality certificates against technical standards and choose reputable manufacturers based on design requirements. Reject products during installation, avoiding short-term gains at the expense of long-term system safety.
(2) Handling and prevention of installation quality issues.
Ensure close coordination with relevant trades, particularly civil engineering, by sharing technical specifications in advance to align timelines and ensure quality. For example, during pre-embedding and pre-opening, civil engineers must ensure diagonal accuracy within ±2mm and support wall-mounted installations to allow cabinet doors to open beyond 180°.
Standardize wire entry lengths, controlling errors within (4±1)mm. Ensure one pipe per hole, match pipe and hole diameters, and use protective rings for steel pipes. Repaint damaged surfaces and use thin drills for additional openings if needed.
For grounding, avoid direct welding to the cabinet; use galvanized flat or round steel connected to dedicated grounding bolts or plates inside the cabinet.
(3) Handling and prevention of common wiring quality issues inside cabinets.
Ensure wire ends are insulated, wiring is neat and secured, and leave 5–10cm of slack inside the cabinet. Limit each terminal to one wire, or use a flat washer for two wires.
Clearly distinguish phase, N, and PE wires with correct color codes. Ensure all circuits are properly labeled, and complex cabinets should include wiring diagrams from manufacturers.
4. Conclusion
The installation of power distribution cabinets is a critical aspect of building electrical systems, impacting costs, operational safety, and the protection of lives and property. Therefore, it is essential to prioritize cabinet quality from the source—through careful selection of equipment, materials, and construction practices. By leveraging technical standards, rigorous supervision, and inspections, issues can be mitigated during installation, ensuring the overall quality and safety of the building electrical system.
