ENE/Solar/TBT-ENE-008

Solar Farm Cable Trenching

Energy & Renewables › Solar › Solar Farm Cable Trenching

Presenter		Project
Location		Date

Solar farm cable trenching installs DC and AC cabling between panel arrays, inverters, and the grid connection.
Trenches are typically 600mm to 1200mm deep and may extend over several kilometres across the site.
DC cables from solar arrays carry live voltage during daylight and cannot be fully de-energised.
Multiple cable circuits may share the same trench, requiring careful separation and identification.
Agricultural land used for solar farms may contain field drains, water pipes, and unrecorded services.
Trenching in clay soils creates collapse risk; deeper trenches require battering or temporary support.
Cable laying involves repetitive manual handling of heavy cable drums and pulling equipment.
Warning tape, marker boards, and sand surround must be installed to protect buried cables from future damage.
The Electricity at Work Regulations 1989 apply to all cable installation and connection activities.
Backfilling must follow the cable manufacturer specification for bedding material and compaction layers.

Electrocution risk	DC cables from solar panels are live in daylight. Contact with damaged or exposed conductors causes fatal electrocution.
Trench collapse	Long, continuous trenches across open ground collapse without warning, burying workers in unsupported sections.
Future cable strikes	Without proper marking and protection, buried cables will be struck by future agricultural or construction excavations.

Don't

Scan for existing services before trenching across any part of the solar farm.
Support or batter trench sides where depth exceeds 1.2 metres in any soil.
Treat all DC cables as live during daylight hours and use DC-rated tools.
Install warning tape and marker boards above all buried cable routes.
Use correct cable bedding material and compaction as specified by the manufacturer.
Separate DC and AC circuits within shared trenches according to the design.
Provide safe access and egress points at regular intervals along long trenches.
Use mechanical handling for heavy cable drums to reduce manual handling injuries.
Test all cable circuits for insulation resistance before backfilling the trench.
Record as-built cable positions accurately for the operations and maintenance manual.

DON'T assume agricultural land is free from buried services or field drains.
DON'T enter unsupported trenches deeper than 1.2 metres in any soil type.
DON'T handle or cut DC solar cables without treating them as live.
DON'T backfill over cables without installing warning tape and marker boards.
DON'T mix DC and AC cables in the same trench without designed separation.
DON'T compact backfill directly onto cables without the specified bedding layer.
DON'T leave long trench sections open unattended without barriers and signage.
DON'T pull cables with excessive force that exceeds the manufacturer bend radius.
DON'T skip insulation resistance testing before burying newly installed cables.
DON'T deviate from the designed cable route without engineering approval.

See also: DC Electrical Safety (Solar) | Ground Mounted Solar Farm Safety

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