How to Ensure the Quality of Low-Voltage Switchgear?

The quality assurance of low-voltage switchgear relies on closed-loop management throughout the entire process, from design and production to inspection. The core lies in three key aspects: a standardized system, process inspection, and factory testing, ensuring the long-term safe and stable operation of the equipment under complex working conditions.

 

1. Establish a Comprehensive Quality Management System

Implement Total Quality Control (TQC), with the project manager as the primary responsible person and the Quality and Safety Department providing full supervision.

All production activities are carried out in accordance with national standards (such as GB/T 7251.1) and the company's "Production Operation Instructions" to ensure process consistency.

Use calibrated measuring instruments to eliminate quality hazards caused by measurement deviations.

 

2. Segmented Inspection of Key Processes

Each process must be inspected after completion to prevent the accumulation of defects:

Machining Stage: Check the cabinet's height, width, and depth dimensional deviations (≤1%), diagonal difference ≤5mm, and ensure structural verticality.

Surface Treatment: The coating must be uniform, free of flow marks and bubbles, with strong adhesion, meeting thickness standards, and a flatness of ≤3mm per meter.

Component Assembly: Verify that the model and quantity match the drawings; ensure secure installation; and ensure instruments and buttons are horizontally and vertically aligned, meeting ergonomic requirements.

 

3. Electrical Connection and Busbar Installation Quality Control

Wiring Process: Wire connections must be secure, with a maximum of two wires connected to each terminal; moving parts should use multi-strand copper wire with sufficient slack.

Busbar Processing: Surface should be nickel-plated or tin-plated, free of cracks and wrinkles; lap bolts should be tightened with a torque wrench (e.g., M6 bolt torque 78.5～98.1 N·m) to ensure reliable contact.

Safety Distance: The distance between exposed live parts and between the live parts and the casing should be ≥20mm to prevent short-circuit risks.

 

4. Pre-shipment Full Functional Testing Each device must pass the following tests before leaving the factory

Insulation Resistance Test: ≥1MΩ

Power Frequency Withstand Voltage Test: 2.5kV for 1 minute without breakdown

Mechanical Operation Test: Smooth switching between the three positions of the drawer unit (run/test/isolation), and reliable interlocking

Type Test (New Products): Sent to a nationally accredited laboratory for short-circuit withstand, temperature rise, and other extreme tests.