Characteristics of the plum rain season: prolonged rainfall, high humidity, frequent short-lived thunderstorms, muddy road surfaces, and poor visibility. In power‑construction projects, activities involving working at height, live electrical work, excavation pits, and lifting operations significantly increase risks. Risk management is organized into five key areas: safety control, civil engineering foundations, electrical installation, equipment protection, and emergency management.

I. General Personal and Electrical Safety (of Paramount Importance)

1 , Mandatory Work Stoppage Requirements During Thunderstorms and Rainfall

When thunder is heard or lightning is seen, or when a weather warning for thunderstorms is issued, immediately cease all work at height, including pole erection, wire stringing, lifting operations, cable withstand voltage testing, and related tests, as well as climbing poles. Personnel shall evacuate towers, excavation pits, and areas occupied by heavy machinery, and keep a safe distance from transmission towers, lightning rods, and metal scaffolding.

Allow to stand after the thunderstorm 30 Resume work in a few minutes.

2 , Leakage protection for temporary electrical use

All construction distribution boxes, welding machines, water pumps, and lighting fixtures shall be equipped with Class II residual current devices, and the grounding resistance shall be periodically retested.

Cables shall be installed overhead; they must not be submerged in water or dragged along the floor, and any damaged cables are to be replaced immediately. Distribution boxes shall be elevated. 30cm Above, a rainproof canopy has been installed, and the box door is closed to ensure waterproofing.

Used in damp excavations and basements 12V Safety extra-low voltage lighting, strictly prohibited. 220V The luminaire is directly submerged in water.

3 , Anti-slip Measures for Heights and Scaffolding

Before working on poles, cable trays, or rooftops, remove standing water and moss, and wear non-slip insulated footwear and double‑hook safety harnesses; install anti‑slip mats on pole‑tower steps and scaffolding.

The scaffolding foundation shall be thoroughly compacted, raised, and provided with drainage ditches to prevent waterlogging, settlement, and tilting; prior to daily work commencement, inspect the scaffold structure for deformation and verify that all couplers are securely tightened.

4 , Prevention of collapse and flooding in excavations and trenches

Excavate trenches, cable trenches, and equipment foundations with increased slope allowances; depth ≥ 1.5m Install additional steel sheet piling; trench edge 1m Piling of soil, steel materials, and utility poles is prohibited within the premises.

Each excavation pit is equipped with submersible pumps to continuously pump out accumulated water, and drainage ditches are excavated along the trench sides to prevent surface runoff from entering. After rainfall, the slope is first inspected for cracks and seepage; only when there is no risk of collapse are trenching operations commenced.

5 , Equipment and Personal Protective Equipment

Cranes and excavators shall be reliably grounded, and prolonged outdoor storage should be avoided in rainy weather. Wire ropes must be thoroughly dried and lubricated to prevent rust; any rope with excessive rust‑induced wire breaks shall be scrapped immediately.

Ensure that raincoats, insulated rain boots, and waterproof insulated gloves are fully equipped; in wet environments, do not touch metal components or cable joints with bare hands.

II. Civil Engineering Foundation Construction (Pole Foundations, Transformer Substation Foundations, Cable Trenches)

1 Concrete Pouring Control

For light rain, a rain shelter must be erected; for heavy rain, concrete placement should be halted. The freshly placed surface layer should be promptly covered with plastic sheeting to protect it from rain-induced erosion and to prevent sand loss and segregation.

After rainfall, any standing water and sludge on the subgrade must be thoroughly removed; concrete placement with mud present is strictly prohibited. Aggregate materials shall be covered to protect them from rain, and the moisture content of aggregates must be closely monitored and the mix proportions adjusted in real time.

Extend the curing and covering period; do not erect poles or lift equipment until the foundation has reached its design strength.

2.  Earthwork backfilling

The backfill soil shall be free of silt, wet clay, and standing water, and must be compacted in layers. Backfilling is prohibited on rainy days; after rain, the soil material must be allowed to dry before resuming construction.

Grounding Engineering

During the plum rain season, soil saturation results in low grounding resistance readings; however, these values tend to rebound once the soil dries after rainfall. After a rain event, re‑measure the grounding resistance, and if it fails to meet the required standards, install additional vertical grounding electrodes.

Apply anti-corrosion asphalt paint promptly to the welded joints of the grounding flat steel; exposure to rainwater can cause rust, so apply two additional coats.

III. Core Moisture-Proof Measures for Electrical Installation, Cabling, and Equipment Installation

1 Cable Laying and Splicing

Elevate cable reels and cover them to protect against rain, preventing the cable sheath from becoming waterlogged and cracking; before laying, wipe away any standing water on the cable surface.

It is strictly prohibited to manufacture cable intermediate joints or terminations in rainy weather when the air humidity exceeds… 80% Stop heat shrinking / Cold‑shrink installation: When installation is unavoidable, erect a sealed rain‑proof canopy and use a dehumidifier and hot‑air gun to dry the core conductors.

A drainage slope shall be provided within the cable trench, and a sump shall be installed in each manhole. Upon completion of cable laying, conduit openings shall be promptly sealed to prevent rainwater from backflowing into the distribution room and transformer substation.

2 , installation of high- and low-voltage switchgear, pad-mounted substations, and transformers

Upon arrival, immediately store the equipment indoors to protect it from rain; if temporarily stored outdoors, elevate it on pallets. + Full‑coverage rainproof tarp; upon unpacking, inspect for condensation or standing water—do not install if the interior is damp.

The transformer substation foundation has been raised, ventilation and moisture‑proof louvers have been installed at the base of the cabinet, and desiccant has been placed inside. The sealing strips have been inspected and found to be in good condition, and all door gaps and cable entry points have been tightly sealed.

After moisture ingress, current and voltage transformers, switches, and secondary components shall be dried with low‑temperature hot air; wiring may proceed only after passing insulation testing.

3 , insulators, hardware, and conductor installation

Porcelain insulators and composite insulators are prone to contamination and flashover in rainy conditions; wipe them dry before stringing. Ensure hardware bolts are rust‑proofed and re‑tighten them after rain.

Avoid stringing conductors during heavy rain, as standing water on the lines can cause slipping; when tensioning the conductors, implement additional anti‑slip measures. After rainfall, inspect new conductors for discoloration due to water immersion and signs of corrosion.

4 , Insulation Test Control

In the high-humidity conditions of the plum rain season, insulation resistance readings may be distorted; therefore, cables, switchgear, and transformers should be thoroughly dried before testing. If ambient humidity exceeds the specified limit, withstand voltage tests and insulation resistance measurements should be postponed.

After rainfall, insulation must be retested; if it fails, identify and address any moisture‑induced defects, then ventilate and dry the equipment until it meets the required standards before restoring power.

IV. Material Storage and Finished Product Protection

1 All insulation materials (heat-shrink tubing, insulating tape, current transformers, switchgear, and cables) are stored in a sealed warehouse equipped with dehumidifiers, with the floor raised to prevent moisture ingress.

2 Steel, angle steel, and flat steel shall be stacked outdoors on elevated pallets and covered with waterproof tarpaulins; surface water shall be drained daily, and anti-rust paint shall be applied at regular intervals.

3 Cable terminations and secondary wiring terminals that have been completed shall be wrapped with waterproof cling film to prevent condensation-induced short circuits.

V. On-site Management, Inspections, and Emergency Response

1 Pre-shift and post-rain inspection system

Daily pre‑work inspections and post‑heavy‑rain special checks: slope collapses, electrical leakage hazards, equipment moisture damage, scaffold settlement, and drainage system blockages.

2 , Meteorological Coordination-Based Work-Stoppage Mechanism

Designate personnel to monitor weather forecasts, and in the event of continuous heavy rainfall or an orange-level or higher thunderstorm warning, suspend all outdoor electrical construction activities without exception.

3 , Emergency supplies fully stocked

Submersible pumps, waterproof tarpaulins, dehumidifiers, heat guns, insulated rescue ropes, leakage‑current detection tools, and sandbags (for sealing excavation pits and preventing backflow at the entrances of transformer substations).

4 Special inspection prior to energization

Pre‑commissioning inspection: Ensure that trench drainage is unobstructed, cabinet surfaces are free of condensation, cable conduit openings are properly sealed, grounding is intact, and insulation levels meet specifications. Only proceed with energization after confirming there are no risks of water accumulation or moisture ingress.

VI. Key Prohibitory Provisions

1 , climbing poles, stringing conductors, lifting operations, and high-voltage testing during thunderstorms;

2 , manufacturing cable joints in high-humidity conditions and outdoors without rain protection;

3 • Accumulated water in the excavation has not been pumped out; trenching operations are being carried out on a cracked slope.

4 , electrical leakage protection, welding with cables submerged in water, and operation of power tools;

5 , Equipment was connected and energized directly without being dried after becoming damp.