Installation of Transformer Boxes and Distribution Boxes

Transformer and distribution boxes must be installed following strict pre-installation checks, proper positioning, grounding, wiring, and fixation procedures to ensure safety and operational reliability.Pre-Installation RequirementsBefore installation, ensure that indoor ceilings and walls are finished with no water leakage, and the ground leveling layer and foundation are completed and inspected. Embedded conduits, reserved holes for incoming and outgoing lines, and other embedded parts must be verified for compliance with design standards . Transformers and distribution boxes should only be installed after confirming that all equipment specifications, certificates, and factory test records are complete and correct .Positioning and FixationTransformers should be positioned accurately according to design drawings, with horizontal and vertical alignment deviations not exceeding ±25mm. Maintain a minimum distance of 800mm from walls and 1000mm from doors if not specified .Small to medium transformers can be positioned using forklifts with wooden boards and blocks to prevent damage, while large transformers require truck cranes or chain hoists .Seismic fixation is required for transformers with rollers, using detachable braking devices or removing rollers after positioning. Dry-type transformers can be placed directly on concrete floors with metal tracks .Distribution boxes should be surface-mounted or flush-mounted according to design, with firm installation and correct height for maintenance access .Grounding and SafetyThe neutral point of transformers must meet grounding resistance requirements, and all enclosures, supports, and casings should be reliably connected to protective conductors using copper core flexible wires of at least 4mm² .Doors of distribution rooms and static compensator enclosures must also be grounded. Surge protective devices (SPD) should be verified for correct model and performance before connecting power supply lines .Fire protection requirements must be met by sealing inlets and outlets of cabinets, stands, and boxes .Wiring RequirementsSecondary circuit wiring should comply with design specifications, using insulated copper wires rated at 450/750V or higher. Current-carrying circuits require a minimum cross-section of 2.5mm², while other circuits require at least 1.5mm² .Circuits of different voltage levels, AC/DC lines, and computer control lines should be bundled separately and clearly identified. Wiring should not obstruct draw-out or plug-in units .Maintain proper bending radius for cables, ensure tight connections without damaging wire cores, and use non-combustible materials for boxes and panels .Component Assembly and CommissioningAssemble dismantled components such as tank covers, conservators, and relays according to manufacturer specifications .Lubricate moving parts like on-load tap changers and verify that their positions match switch settings .Conduct pre-energization tests for transformer grounding, system grounding, and component functionality. Only after passing these tests should the equipment be energized .Fixation and Maintenance ConsiderationsUse galvanized bolts with anti-loosening parts to secure distribution cabinets, stands, and boxes .Ensure proper ventilation around transformers (minimum 1.25m clearance if enclosed) and provide oil drainage provisions and fire separation walls where necessary .Maintain neat wiring, correct component models, and proper PE bar connections before trial operation . By following these pre-installation, positioning, grounding, wiring, and fixation procedures, transformer boxes and distribution boxes can be installed safely, reliably, and in compliance with design and safety standards.