Solar photovoltaic systems generate DC electricity as soon as they are exposed to daylight. This means panels cannot be fully isolated by simply switching off the AC supply. Installers face electrical, working at height, and manual handling risks throughout the installation process. This talk covers the specific hazards and safe working practices for solar PV installation on buildings.
Key Hazards
DC electrical shock from panels that remain live in daylight
Falls from height during rooftop installation work
Manual handling injuries from carrying heavy panels up ladders
Arc flash from damaged DC connectors or incorrectly wired strings
Control Measures
Treat all solar panels as live whenever exposed to any amount of daylight.
Use insulated tools and wear insulated gloves rated for the system voltage during DC work.
Install edge protection or use harness and lanyard systems for all rooftop work.
Use mechanical handling aids to transport panels to roof level wherever possible.
Cover panels with opaque material during wiring and connection activities to reduce voltage.
Ensure all DC cables are correctly labelled, routed away from sharp edges, and UV resistant.
Verify string voltages match design calculations before connecting to the inverter.
Isolate the AC and DC sides before carrying out any maintenance or fault-finding work.
Ensure all installers hold MCS-accredited solar PV installation qualifications.
Emergency / Rescue
If someone receives a DC electric shock, do not touch them if still in contact. Cover or shade the panels to reduce voltage if safe. Isolate the DC isolator. Call 999 and begin CPR if the casualty is not breathing.
Remember
Solar panels generate DC electricity whenever exposed to daylight and cannot be switched off
Always use insulated tools and gloves rated for the system DC voltage
Edge protection or fall arrest must be in place for all rooftop installation work
Cover panels with opaque sheeting during wiring to reduce the risk of electric shock
Isolate both AC and DC sides before carrying out any maintenance or fault finding
Only MCS-accredited installers should carry out solar PV installation work
Applicable Legislation: Electricity at Work Regulations 1989 · Work at Height Regulations 2005 · BS 7671 (IET Wiring Regulations) · MCS Installation Standards