Wire and cable acceptance upon site entry is a critical link in ensuring project safety. The following steps and specifications must be strictly implemented:

I. Pre-Acceptance Preparation

1. Notify Relevant Parties:​ Notify the Supervision Unit and the Owner’s Representative in advance to schedule a joint inspection time.

2. Prepare Documentation:​ Have design drawings, specification documents, and acceptance record forms ready.

3. Acceptance Tools:​ Steel tape measure, Vernier caliper, Insulation resistance tester (Megger), etc.

II. Documentation Verification (Mandatory)

All documents listed below must be complete and valid.

⚠️ Note:​ Cables without valid certification documents shall not be allowed entry to the site.

III. Physical Acceptance Standards

1. Visual Inspection

• ✅ Insulation/Jacket layers are intact and undamaged, with uniform thickness and consistent color.

• ✅ No defects such as flattening, twisting, cracking, or blistering.

• ✅ Conductors show no oxidation, rust, breakage, or loose stranding.

2. Marking & Labeling Check

• Markings on the outer sheath shall be spaced at intervals not exceeding 1 meter.

• Content:​ Manufacturer's name, Specification/Model, Rated voltage, Length, CCC certification mark.

• Markings must be legible and remain clear after rubbing 5 times with a cloth dampened with gasoline or alcohol.

3. Dimensional Measurement

• Length Tolerance:​ Error shall not exceed 0.5% of the total length.

• Insulation Thickness:​ Measured with a Vernier caliper; must comply with GB/T 5023.3-2008.

• Conductor Resistance:​ Copper conductor resistance at 20°C ≤ 0.017241 Ω·mm²/m.

4. Electrical Performance Testing

• Insulation Resistance:

  • Low-voltage cables (0.6/1kV): ≥ 0.5 MΩ·km.

  • After immersing wires in water for 24 hours, test with a 750V Megger: Resistance > 0.5 MΩ.

  • For wires and cables, test with a 1000V Megger: Resistance > 10 MΩ.

IV. Sampling & Laboratory Testing Protocol

1. Sampling Principle

• Same manufacturer, same batch, same model, same specification.

• Sampling Ratio:​ Minimum of 1 sample per batch.

• Energy-Saving Acceptance:​ Spot check ≥10% of total specification types, minimum 2 types.

2. Non-Compliance Handling

• First test fails → Double sampling​ for re-verification.

• Re-verification fails → Reject the entire batch; use is strictly prohibited.

V. Common Issues & Disposal

VI. Visual & Manual Material Inspection

Copper Core:

• National Standard (GB) Copper:​ Purplish-red, bright luster, soft, not easy to break.

• Non-Standard Copper:​ Yellowish/dull, many impurities, hard, brittle.

Insulation/Sheath Material:

• Flame Retardant Material:​ Good flexibility/toughness; no white marks or cracking when bent.

• Inferior Material:​ Turns white when bent, hard, brittle, easy to crack.

Stripping Check:​ No internal impurities or air bubbles; insulation does not stick to the conductor.

VII. Simple On-Site Electrical Tests

Insulation Resistance Test:

Use a Megger to test phase-to-phase and phase-to-ground resistance. For LV cables, higher values are better. Low values indicate moisture/damage—reject immediately.

Continuity Test:

Test each core of multi-core cables for continuity. Ensure no open circuits, short circuits, or cross-connections.

VIII. Specialized Acceptance for Specific Cables

• Flame Retardant / Fire Resistant Cables:​ Verify markings and test reports. A simple lighter test can be performed (self-extinguishing upon removal from flame indicates pass).

• LSZH (Low Smoke Zero Halogen) Cables:​ Outer sheath should have no halogen odor; burning produces little smoke and no black smoke.

• Armored Cables:​ Steel tape/wire armor must be neatly arranged, free from rust, and lap joints must follow specifications.

IX. Sample Retention & Sealing

• Cut and seal 1–2 meters of sample from each batch, sign for retention, for future re-testing or dispute resolution.

• Sign for warehousing upon acceptance; directly reject non-conforming batches, take photos as evidence, and arrange return/replacement.

X. 8 Conditions for Immediate Rejection

1. Missing Certificate of Conformity, 3C mark, or Test Report.

2. Model/Specification does not match the contract.

3. Faint or missing markings on the outer sheath.

4. Damaged jacket, water ingress, or moisture.

5. Undersized conductor diameter or insufficient insulation thickness.

6. Dull, impure, hard, or brittle copper core.

7. Short length or missing meters on the drum.

8. Low insulation resistance or presence of short/open circuits.

XI. Key Reference Standards

• Code for construction quality acceptance of building electrical engineeringGB50303-2015

• Code for acceptance of energy efficient building engineeringGB50411-2007

• Conductors of insulated cablesGB/T3956-2008