ENE/Solar/TBT-ENE-007

DC Electrical Safety (Solar)

Energy & Renewables › Solar › DC Electrical Safety (Solar)

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Solar photovoltaic panels generate DC electricity whenever exposed to daylight, and cannot be switched off.
DC voltages in solar arrays can exceed 1,000 volts — enough to cause fatal electrocution.
Unlike AC systems, DC arcs are harder to extinguish and can sustain fire-starting temperatures.
Standard AC isolation procedures do not apply; solar DC circuits remain live during daylight hours.
Damaged cables, connectors, or panels can create exposed live DC conductors without any visible warning.
DC shock is particularly dangerous because it causes sustained muscle contraction, preventing self-rescue.
Fire fighters face unique risks because solar panels continue generating electricity during building fires.
The Electricity at Work Regulations 1989 apply equally to DC and AC electrical systems.
Installers must be trained specifically in DC electrical safety and solar PV system hazards.
Rapid shutdown systems are increasingly required to reduce DC voltage risks during emergencies.

Cannot be switched off	Solar panels generate electricity in any daylight, including overcast conditions. There is no off switch for the DC source.
Fatal shock risk	String voltages exceeding 1,000V DC cause lethal electrocution. DC shock is harder to release from than AC shock.
Fire hazard	DC arc faults sustain higher temperatures than AC arcs and are harder to extinguish, creating serious fire ignition risk.
Legal duty	The Electricity at Work Regulations 1989 require that work on or near DC solar systems follows safe isolation procedures.

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See also: Ground Mounted Solar Farm Safety | Rooftop Solar PV Installation

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