Substation Construction Safety

Substations transform and distribute electrical power from high voltage to lower voltage networks.
Construction near live electrical infrastructure poses lethal risks from electrocution and arc flash.
Minimum safe approach distances must be maintained from all live HV equipment at all times.
The Electricity at Work Regulations 1989 govern all aspects of safety during substation construction.
Substations contain transformers filled with mineral oil, which is a fire and environmental hazard.
Heavy items such as transformers, switchgear, and busbars require planned lifting operations.
Cable trenches, ducts, and pits within substations create confined space and tripping hazards.
Earthing systems must be installed correctly to protect workers from fault current during construction.
Existing substations may remain partially energised while new sections are being constructed nearby.
Only SAP (Senior Authorised Person) or AP (Authorised Person) qualified staff may access live areas.

Prevent electrocution	Contact with HV equipment at substations is nearly always fatal. Safe distances and isolation are critical.
Arc flash protection	Arc flash events at substations can produce blast pressures and temperatures that cause fatal burns.
Environmental protection	Transformer oil spills contaminate land and water — bunded containment is a regulatory requirement.
Legal compliance	The Electricity at Work Regulations 1989 require safe systems of work for all substation activities.

Do

Don't

Maintain minimum safe approach distances from all live HV equipment at all times
Verify isolation and earthing before working on any de-energised substation equipment
Use only SAP or AP authorised personnel for access to live or energised areas
Follow the site-specific safety rules document issued for the substation at all times
Wear arc-rated PPE as specified in the risk assessment for the work zone
Use a planned lifting operation for transformers, switchgear, and heavy components
Ensure oil bunding and spill containment is in place before transformer installation
Brief all workers on emergency procedures including electrical incident first aid
Install temporary barriers and signage to prevent unauthorised access to live areas
Coordinate all work activities with the distribution network operator before starting

DON'T approach or reach towards live HV equipment without authorisation and clearance
DON'T climb onto transformer tanks, busbars, or structures without a safe system of work
DON'T use metallic ladders, tapes, or scaffolding near live HV equipment
DON'T carry out excavation inside substations without checking for buried HV cables
DON'T enter live switching rooms without SAP or AP qualification and authority
DON'T store flammable materials near transformer compounds or oil-filled equipment
DON'T assume equipment is dead because it appears switched off — always prove dead
DON'T interfere with earthing connections or safety interlocks on substation equipment
DON'T allow crane booms, plant jibs, or loads to enter HV exclusion zones
DON'T carry out hot works near transformers without a specific fire risk assessment

See also: High Voltage (HV) Safety | Arc Flash Awareness

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