Underground service

Single-family homeowners and subdivision developers seeking to have underground electric service should call Coastal Electric Cooperative before beginning construction. The Cooperative requires the homeowner or developer to first install underground conduits. A staking engineer will meet with the developer on-site and design a conduit plan. Once the conduit has been installed and inspected, the Cooperative will install and connect the underground cable.

If you’re building a subdivision with underground utilities, contact Brian Hayes (912) 880-4027 or (912) 312-5132.

Underground Conduit Installation Guidelines 

 

Underground Secondary Services:

The conduit shall be installed in a straight run between the meter base and the secondary pedestal provided for the service. The conduit, with a pull string installed inside, shall be glued and buried 30” below final grade when installed to a pole or secondary pedestal. Two sweeping elbows are preferred, and three will be permitted only under special circumstances. The elbow nearest the secondary pedestal shall be inserted beneath the pedestal. If a stub-up from a transformer is not provided for service to a residence, stub up service conduit behind the transformer and install a pull string to that point. The length of the conduit, including the vertical and above-grade sections shall not exceed 250’ in length. The conduit shall be schedule 40 PVC and of the size indicated below.

Service Size & Type

Conduit Size
200/320 amp 3”
400/600 amp 4”
Other to be determined

Prior to the closure of the trench, Coastal Electric Cooperative will be provided an opportunity to inspect the installation. Provided a request for an inspection is made by 8:00 a.m., the inspection will typically be conducted on the afternoon of this same day. After passing the inspection, the trench shall be backfilled and tamped by the installer. While backfilling, warning tape will be installed 12” below final grade.

Underground Primary Distribution:

The conduit systems required for underground facilities within subdivisions and commercial developments are dictated by their unique needs and will be specified on a case-by-case basis. Coastal Electric Cooperative will work closely with the developer to determine the most efficient design possible. Once determined, the Developer will be provided with a conduit plan that outlines the specific requirements of the conduit system necessary to provide underground service. The developer will be expected to install this conduit system in accordance with the design requirements provided.

In general, underground primary distribution will require two 2½” schedule 40 PVC conduits. The conduits shall be glued and installed 42” below final grade. Single-phase lines will require two conduits while three-phase lines will require two 4” and one 2½” conduits. A 500 lb jet string shall be installed in each conduit. Conduits will typically be stubbed up on specified lot lines for the installation of the electrical equipment. Coastal Electric Cooperative will furnish and install the equipment that is required for the development.

The secondary conduit to secondary pedestals shall be 4” schedule 40 PVC. Two 3” conduits shall be stubbed up behind the transformer locations with 2’ of separation for future services to residences.

During the course of installation, Coastal Electric Cooperative will periodically inspect the conduit installation. These inspections are aimed at resolving problems prior to the installation of the cable. These inspections will be conducted within the same time frame as those for secondary conduits.

Underground Primary Express Feeders:

Depending upon the scale of the development and the load to be served, some developments may require primary express feeders. The underground cables used for these feeders are much larger than those used for underground primary distribution. As such, they are much more expensive than their overhead equivalent and, therefore, require special consideration.

When an express feeder is required, developers will have the option of overhead or underground construction. Overhead express feeders will be provided at no cost, and the routing of these facilities will be negotiated with the developer. The aim will be to provide the necessary electrical infrastructure while minimizing the impact on the development. When an underground express feeder is requested for a subdivision, a contribution will be required. In general, the amount of the contribution will equal the incremental cost of providing the requested underground express feeder in lieu of the proposed overhead equivalent. The developer will furnish the required conduit system.

Underground express feeders will typically require two 6” and one 2½” schedule 40 PVC conduits per circuit. These conduits shall be glued and buried 42” below final grade. A 500 lb jet string shall be installed in each conduit. Coastal Electric Cooperative will provide and install the necessary vaults and cabinets for the express feeders.

  • To schedule underground secondary conduit inspections
    • Contact our Operations staff at 880-2222 or (800) 421-2343, ext. 2222
  • To schedule underground primary conduit inspections
    • Contact the Field Engineering Technician responsible for the project:
      • Bob Bitzer  – 880-2258, (800) 421-2343, ext. 2258 or 912-977-5938
      • C.J. Howard – 880-2242, (800) 421-2343, ext. 2242 or 912-429-6523
      • B. J. Strickland – 880-2238, (800) 421-2343, ext. 2238, or 912-617-1628
  • For general questions about our service requirements
    • Contact our Operations staff at 880-2222 or (800) 421-2343, ext. 2222

Guide Drawings

Solar Interconnect Policy and Agreement

Secondary Services

Primary Distribution and Express Feeders