Online Consultation The quality inspection of the electrical cabinet after processing needs to be comprehensively tested from the dimensions of structural accuracy, appearance quality, electrical performance, protective performance, functional integrity, etc., to ensure that the product meets the design standards and usage requirements. The following are specific inspection items, methods, and judgment criteria:
1、 Structural and installation accuracy inspection
1. Dimensional and positional tolerance testing
Cabinet dimensions
Use a steel tape measure and vernier caliper to measure the length, width, and height of the cabinet, with an error controlled within ± 1.5mm of the design dimensions (such as a standard cabinet measuring 800mm × 600mm × 2200mm, with an allowable deviation of ± 3mm).
Diagonal difference: The diagonal length difference between the top and bottom of the cabinet is ≤ 3mm (when the diagonal length is greater than 2000mm, the allowable deviation is ≤ 5mm).
Flatness and verticality
Planeness of door and side panels: Use a 1m ruler and a feeler gauge to check, with a gap of ≤ 2mm/m.
Verticality of cabinet: measured with a right angle ruler or laser plumb line, the deviation of verticality between the column and the bottom surface is ≤ 1.5mm/m.
2. Installation hole accuracy
Hole spacing: Measure the center distance of the installation holes with a caliper, with an error of ≤± 0.5mm (if the distance between component installation holes is 200mm, the allowable deviation is ± 0.3mm).
Thread hole quality: Use a thread plug gauge to check and ensure that the screw is screwed in smoothly without slipping or chipping.
Installation of guide rails: The drawer cabinet guide rails should be parallel and evenly spaced, and there should be no jamming during push-pull testing. The shaking amount when pulled out should be ≤ 2mm.
2、 Appearance and surface treatment inspection
1. Appearance defect inspection
Visual inspection:
No obvious scratches, dents, or deformations (scratches longer than 10mm or deeper than 0.5mm are not qualified).
The surface of the weld seam should be smooth, without weld beads, undercutting, or porosity (undercutting depth>0.5mm or continuous length>10mm requires repair welding).
Coating quality:
Test adhesion using the scratch method (ISO 2409 standard): Use a blade to scratch a 1mm × 1mm grid, apply 3M tape and peel off. The number of coating peeling grids should be ≤ 5% (reaching level 4B is qualified).
Coating thickness: measured with an electromagnetic induction thickness gauge, the coating thickness on the metal surface must be ≥ 80 μ m (outdoor cabinet ≥ 120 μ m), and uniform without sagging.
2. Identification and protection inspection
Nameplate information:
The nameplate should include product model, rated voltage, protection level, manufacturer information, etc. The pasting position should be upright, and the handwriting should be clear and recognizable.
Sealing performance:
The door panel sealing strip should be installed firmly. After closing the cabinet, use a feeler gauge to check the gap, and the uniformity should be ≤ 1.5mm (IP54 cabinet gap should be ≤ 1mm).
3、 Electrical performance testing
1. Grounding system inspection
Grounding resistance measurement:
Use a grounding resistance tester to measure the resistance between the cabinet grounding terminal and various metal components (such as door panels and installation beams), which should be less than 0.1 Ω (standard requirement ≤ 4 Ω, higher requirement here).
Cross connection reliability:
The moving parts such as hinges and door locks need to ensure grounding continuity through jumper wires (cross-sectional area ≥ 4mm ²), and the jumper points should not be oxidized or loose.
2. Insulation performance test
Insulation resistance measurement:
Disconnect all power components and use a 500V megohmmeter to measure the insulation resistance between phases and between phases and ground, which should be ≥ 10M Ω (≥ 2M Ω in humid environments).
Voltage withstand test:
Apply 2000V AC voltage to the main circuit (test time 1 minute) without breakdown or flashover phenomenon (control circuit test voltage 1000V).
3. Component function verification
Component action test:
Manually operate circuit breakers, contactors, and other components to check whether the opening and closing are flexible, and whether the indicator lights and instrument displays are normal.
Wiring correctness:
Refer to the circuit diagram and use a multimeter to check the conductivity level of the wiring, ensuring that the wire number is consistent with the drawing and the terminals are securely crimped without any loose connections (batch testing can be performed using a harness tester).
4、 Protection and environmental performance testing
1. Verification of Protection Level (IP Level)
Dustproof test (IP5X/IP6X):
Place the cabinet into a dust test chamber (with a talc concentration of 2kg/m ³) and continue to extract dust for 8 hours. After that, there should be no visible dust deposition inside (suitable for outdoor cabinets or industrial environment cabinets).
Waterproof test (IPX4/IPX5):
IPX4: Spray water from any direction with a nozzle (flow rate of 10L/min) for 15 minutes without any water entering the interior.
IPX5: Use a 6.3mm nozzle to spray water from a distance of 3m (flow rate of 12.5L/min) for 3 minutes, with no obvious water stains inside.
2. Temperature and vibration resistance tests (optional)
Temperature rise test:
Simulate full load operation, use thermocouples or infrared thermal imagers to monitor the temperature of components and cabinet surfaces, with a temperature rise of ≤ 60K (such as circuit breaker contact temperature<105 ℃, cabinet surface temperature ≤ 55 ℃).
Vibration test:
Apply vibration with a frequency of 10~50Hz and an amplitude of 0.15mm to the cabinet (for 30 minutes), and check whether the components are loose and whether the wires are detached.
5、 Functional integrity verification
1. Drawer and door operation test
Drawer push-pull performance:
The drawer should be able to be easily inserted and withdrawn, with accurate locking position, and a shaking amount of ≤ 3mm when withdrawn. The mechanical interlocking function should be normal (if the drawer is not fully inserted and cannot be powered on).
Door opening and closing test:
The opening angle of the door panel is ≥ 90 °, there is no jamming when closing, the lock switch is flexible, and the sealing strip is compressed evenly.
2. Identification and wiring specifications
Wire identification:
Each wire must have a clear wire number identification (sleeve printing or terminal marking), the wire number should be consistent with the drawing, and the handwriting should be resistant to alcohol wiping (wiped 5 times with an alcohol cotton ball without fading).
Wiring harness organization:
The wires should be tied neatly, with a bending radius of ≥ 6 times the outer diameter of the wire, avoiding contact with sharp edges. The power and signal wires should be laid separately (with a spacing of ≥ 50mm).
6、 Inspection records and non conformance handling
1. Standardization of inspection records
Fill out the 'Finished Electrical Cabinet Inspection Report', record the inspection items, measured values, and qualified status, and have the inspector sign and confirm.
Attach original test records or instrument printed reports to key data such as grounding resistance and withstand voltage test results.
2. Control of non-conforming products
Rework and repair:
For issues such as size deviation and coating defects, rework shall be carried out according to the "Non conforming Product Handling Procedure" (such as welding repair, re spraying), and re inspection shall be carried out after rework.
Scrap judgment:
If there are serious problems such as insufficient structural strength (such as frame fracture), inadequate electrical safety performance (such as grounding resistance>1 Ω), etc., it will be directly judged as scrap.
