Pre-installation Preparation
Technical and Safety Briefing: Familiarize yourself with design drawings and product manuals; clarify the branch box model, number of circuits, and cable specifications; obtain the work permit corresponding to the voltage level; and designate a safe working zone.
Tool and Equipment Verification: Prepare tools such as a torque wrench, cable stripper, 2500V insulation resistance tester, and earth resistance tester; ensure all insulated tools are within their valid calibration period.
Site Inspection:Confirm the installation location is well-ventilated, dry, and away from flammable or explosive materials and flood-prone low-lying areas; ensure foundation levelness deviation is ≤2mm/m and sufficient space is reserved for operation and heat dissipation.
Main Unit Installation Process
Foundation and Enclosure Positioning: Secure floor-mounted branch boxes to the prefabricated concrete foundation using expansion bolts; for wall-mounted/suspended types, first secure the load-bearing bracket. Ensure enclosure verticality deviation is ≤1.5mm/m and apply weather-resistant sealant at joints to meet protection rating standards.
Cable Laying and Entry: Feed incoming cables to the high-voltage bushings first, followed by outgoing cables; ensure the cable bending radius is ≥15 times the outer diameter, reserve ≥500mm of slack at both ends for operation, and attach clear circuit identification tags.
Standardized Cable Termination: Strip the outer semi-conductive layer and main insulation layer according to manual specifications; wipe the insulation surface unidirectionally with cleaning paper and apply insulating silicone grease evenly; install the stress control tube and T-type/elbow connectors in sequence (prioritizing Phase B, then Phases A and C); outdoor work during rain is strictly prohibited.
Core Component Connection: Precisely insert and lock cable connectors into the branch box's insulating bushings; ensure reliable grounding of the surge arrester tail; install flat washers and spring washers only on the outer side of the incoming/outgoing terminal studs-placing washers inside the bushing is strictly prohibited. Grounding system installation: The metal enclosure of the unit, cable armor, and shielding layers are all reliably connected to the grounding grid; the grounding main busbar consists of a copper bar with a cross-section of ≥25 mm², and grounding electrodes are buried at a depth of ≥0.8 m.