Underground Primary & Secondary
Distribution Lines

The developer or owner shall be responsible for all ditching and backfilling associated with the installation of underground primary and secondary distribution lines.

All underground primary and secondary distribution lines installed by CDE shall be in conduit. The developer or owner shall provide and install the complete conduit system for the underground primary and seconday cables.

All conduits for underground primary cables shall be either Schedule 80 PVC or rigid conduit, except that all elbows shall be constructed of rigid galvanized steel. The size of the conduits shall be four inches for those conduits that will contain three-phase cables, and two inches for those conduits that will contain single-phase cables unless otherwise specified by CDE.

CDE will furnish and install underground secondary conductors for single-phase residential applications only. All conduits for underground secondary cables shall be Schedule 40 PVC, except that all conduits for street crossings shall be Schedule 80 PVC or rigid conduit. The size and number of the secondary conduits shall be as determined by CDE.

Conduits for underground primary cables shall be installed at a depth of not less than 36 inches below final grade. Conduits for underground secondary cables shall be installed at a depth of not less than 24 inches below final grade. Conduits for underground secondary or service conductors may be installed in the same ditch as the conduits for primary cables provided that the primary conduits are on the bottom of the ditch. Conduits in a common ditch must have a minimum of 12 inches of vertical fill between them, and a depth of not less than 24 inches below final grade for the secondary or service conduits must be maintained.

CDE shall be consulted prior to ditching to determine the proper routing of the conduits. Also, it is required that a representative from CDE inspect the conduit installation before it is covered. Earth and all materials used in the ditches are to be tamped to provide proper support for the conduits. Foreign matter (bricks, concrete blocks, boards, bottles, trash, etc.) shall not be placed in ditches. Large rocks shall not be used within 12 inches of the conduits. Compacted gravel shall be used as backfill for all street crossings. The developer or owner shall be responsible for installing a plastic warning tape furnished by CDE 12 to 18 inches above the conduits during backfilling.

Where underground primary or secondary lines will originate from overhead distribution facilities, all conduits mut be installed on stand-off brackets or unistrut and must all be installed on one side of the pole. Spacing of the conduit supports shall not exceed five feet with one support within 12 inches of the top of conduit. All conduits form electrical cables must be installed up the pole to a point no farther away than 18 inches from the CDE system neutral. If requested by the developer or owner, CDE will assist in the installation of the conduit up the pole in the vicinity of energized conductors.

The developer or owner shall be responsible for pouring concrete transformer pads as required. Gravel backfill shall be used in all ditches within three feet of all pad locations. CDE will provide drawings of the pad details.

The developer or owner shall be responsible for preparing foundations for sectionalizing equipment or secondary vaults as required. Gravel backfill shall be used in all ditches within three feet of these locations. CDE will furnish the dimensions for these foundations.

The developer or owner shall be required to execute a contract prior to commencement of work by CDE that makes provisions to pay to CDE the cost difference between the standard overhead construction provided by CDE and the costs incurred by CDE in providing underground primary distribution.