Outdoor Electrical Installations

Outdoor electrical work carries higher risks than indoor — exposure to moisture, physical damage, and greater potential for electric shock. BS 7671 has additional requirements for outdoor and underground wiring.

Cable Requirements

Surface conduit

Metal or PVC conduit for walls/fences

SWA cable

Armoured cable for underground

Rigid buried conduit

PVC conduit ≥450mm deep

Burial Depths

| Location | Minimum depth | |----------|--------------| | Garden (lawn) | 450mm | | Driveway / under paths | 600mm | | Under buildings | Not permitted |

Cables underground must be armoured (SWA) or in rigid conduit to protect against accidental damage.

RCD Protection

All outdoor circuits must be protected by a 30mA RCD. This is mandatory, not optional. Even if the indoor ring circuit has RCD protection at the consumer unit, an outdoor extension should have a dedicated RCD.

IP Ratings

Outdoor sockets and fittings must have an IP rating suitable for their exposure:

  • Sheltered locations: IP44 minimum
  • Exposed to rain: IP55 or better

Part P

All outdoor electrical work is notifiable. This includes:

  • New outdoor socket circuits
  • Outdoor lighting on new cables
  • EV charging points

Always use a registered electrician or notify building control before starting outdoor work.