Electrical Installation of Residential Services

Information provided on this page references the 2007 California Electric Code (CEC).

  1. Service Entrance
  2. Service Grounding / Bonding
  3. Grounding Electrodes [250.52]
  4. Grounding Electrode Conductor
  5. Other Bonding Requirements

Minimum Size of Residential Service & Feeder Conductors [CEC 310.15(B)(6)]

Copper AWGAmps

Conductor Types must be rated for "wet" locations. Conductors exposed to sunlight must be listed/marked "sunlight resistant." [310.8] e.g.: Type THWN conductors.

See Table 310.15(B)(6) for complete list of amperes and conductor types.

Clearances for Service Drops [CEC 230.9 & 230.24]

  • 3 feet from openable:
    • Balconies
    • Doors
    • Fire escapes
    • Ladders
    • Porches
    • Stairs
    • Windows and similar locations
  • 8 feet above any roof surface with a pitch of less than 4 in 12.
  • 3 feet above any roof surface with a pitch greater than 4 in 12.
  • 18 inches when passing over the overhang (eave) portion of the roof, regardless of the pitch, provided the overhang does not exceed 4 feet and the length of the drop above the overhang does not exceed 6 feet
  • 10 feet above grade at the service entrance, also at lowest point of the drip loop, and above areas that are accessible only to pedestrians.
  • 12 feet above residential property and driveways.
  • 1 foot from communications wires/cables at any point in the span including the point of attachment to the building. [800.10(A)(4)]

Service Mast [230.28]

Only service conductors shall be attached to the mast.