What Are The Factory Tests Of Elbow Connectors？

​Elbow connectors (also known as cable elbow joints, elbow cable connectors, insulated elbow terminations, widely used in 10kV/35kV ring main units, transformers and switchgear) undergo a complete series of strict factory inspection and type tests before delivery. All tests follow international standards IEC 60840, IEC 62067 and domestic standards GB/T 12706, GB/T 3840, covering raw material incoming inspection, semi-finished intermediate tests and finished product factory routine tests, plus periodic type verification tests. Below is a full classification and detailed introduction of all factory test items.

1. Raw Material Incoming Inspection Tests (Pre-production Factory Test)

All raw materials entering the workshop must pass sampling tests to eliminate defective raw materials at the source.

Insulation Material Performance Test

Conductor & Copper Fitting Test g.

Semiconducting Shield Material Test .

Accessory Material Inspection .

2. Semi-finished Product Intermediate Workshop Tests

Carried out after single component molding, before full assembly of elbow connectors.

2.1 Insulation Molding Appearance Inspection .

2.2 Semi-conductive Shield Layer Bonding Test .

2.3 Copper Fitting Dimensional & Machining Precision Test .

2.4 Partial Discharge Pre-screening for Single Insulation Shell.

3. Routine Factory Tests (100% Full Inspection for All Finished Elbow Connectors)

Every finished elbow connector must pass all routine items before packaging and shipment; unqualified products are reworked or scrapped.

3.1 Visual & Dimensional Inspection

Appearance check.

Overall dimension test.

Marking inspection.

3.2 DC Resistance Test of Conductive Loop

3.3 Power Frequency Withstand Voltage Test

3.4 Partial Discharge Test (Key Routine Test)

3.5 Sealing Performance Test (Water Immersion / Air Pressure Leakage Test)

Two common factory inspection methods:

Air tightness test.

Water immersion test.

3.6 Assembly Matching Test

Match the elbow connector with standard supporting cable, transformer bushing and grounding fittings. Check smooth insertion, reliable locking, no loose fit or excessive tightness, and complete grounding connection.

4. Periodic Type Tests (Sampling Regularly, Not 100% Routine)

Manufacturers take sample elbow connectors from mass production every 6/12 months to complete full type tests, to verify long-term reliability of product design and production process.

4.1 Thermal Cycle Aging Test.

4.2 Short-time Current Withstand Test (Thermal Stability & Dynamic Stability) .

4.3 Impulse Lightning Withstand Voltage Test.

4.4 Mechanical Strength Test

4.5 Tensile pull-out test .

4.6 Bending mechanical test.

4.7 Impact resistance test.

4.8 High & Low Temperature Alternating Test .

4.9 Hydrolysis & Damp Heat Aging Test .

4.10 Grounding Circuit Continuity Test .

4.11 Salt Spray Corrosion Test

.

5. Packaging & Shipping Auxiliary Inspection

Before leaving the factory, finished elbows pass auxiliary inspection items:

Complete set accessory inspection: grounding wire, lubricating grease, installation instruction manual, packaging parts all complete.

Packaging drop test (periodic sampling): finished carton with product free drop from specified height to confirm packaging protects elbow connectors from damage in logistics.

Batch record review: All test data of the production batch is archived; only batches with full qualified test reports can be released for delivery.

Summary

Factory tests of elbow connectors form a three-layer control system: raw material incoming control, semi-finished intermediate screening, finished product full routine inspection, supplemented by regular sampling type tests. The full test system covers electrical insulation safety, conductive current-carrying performance, mechanical structural strength, sealing waterproof ability and environmental aging resistance, ensuring all factory-outlet elbow connectors meet power system safe operation requirements.

​

​