Cable trenching on solar farm sites involves excavating hundreds of metres of shallow trenches to connect panels to inverters and substations. The work is repetitive and often takes place across open agricultural land with variable ground conditions. Existing underground services, live DC cables from installed panels, and plant movements all present significant risks. This talk covers the hazards and controls specific to solar farm cable trenching operations.
Key Hazards
Striking existing underground services during cable trench excavation
Electric shock from live DC cables already connected to installed solar panels
Trench collapse in sandy or waterlogged agricultural ground conditions
Workers struck by mini excavators tracking along narrow trench routes
Control Measures
Complete a permit to dig and carry out cable detection surveys before excavating any cable trench.
Ensure all existing underground services are marked out and visible before machine excavation begins.
Treat all DC cables from installed solar panels as live during daylight hours unless formally isolated.
Support trench sides where ground conditions are unstable using shoring or battered profiles as required.
Maintain pedestrian exclusion zones along both sides of the active excavation face during machine work.
Brief operatives on the cable trench route plan, connection sequence, and any known buried services.
Use insulated tools and gloves rated to the DC voltage when handling or laying live-side cabling.
Ensure safe crossing points are provided where trenches intersect pedestrian or vehicle routes on site.
Backfill and reinstate completed trench sections promptly to reduce open excavation hazards.
Emergency / Rescue
If someone receives an electric shock from a DC cable, isolate the supply if safe to do so. Call 999 immediately. Do not touch the casualty until the circuit is confirmed as de-energised. Begin CPR if the person is unresponsive.
Remember
A permit to dig and cable detection survey are required before any trench excavation begins
DC cables from installed solar panels are live during daylight and must be treated as energised
Trench sides must be supported or battered in unstable ground to prevent collapse
Pedestrian exclusion zones must be maintained along both sides of the active excavation
Insulated tools and voltage-rated gloves are required when handling live-side DC cables
Applicable Legislation: Electricity at Work Regulations 1989 · CDM Regulations 2015 · HSG47 (Avoiding Danger from Underground Services) · Health and Safety at Work etc. Act 1974