Specifications for Underground Service - General
- An appointment must be made with a JWEMC Engineer to discuss the design, layout and scheduling of the project. Since these are only general specifications, the Engineer may modify the specifications based upon individual project requirements.
- Underground facilities may not be feasible for locations with considerable rock
- A plan of the subdivision shall be furnished to the Engineer prior to the initial meeting in both paper and electronic formats.
- All primary conduit shall be 2" inside the lot line or 5'0" from the back of the easement as specified by the Engineer.
- The trench shall be clean, level and as straight as possible.
- All trenches shall have marking tape installed with 6" of backfill over conduit, then again with 1'6" of backfill on top of the first tape. The marking tape will be furnished by JWEMC located at 25700 Alabama Highway 24 in Trinity.
- All primary conduits shall have a minimum of 3'6" and a maximum of 5'0" of cover at finished grade.
- All secondary, lighting, or services shall have a minimum of 3'0" and a maximum of 5'0" of cover at finished grade except at street crossings, which shall have a minimum of 3'6" of cover.
- Following required inspections, all trenches shall be back filled and compacted by developer/contractor . Any additional fill required due to settlement of back fill shall be developer/contractor's responsibility.
- The developer/contractor will furnish and install all conduits for project as shown on drawing supplied by the Engineer.
- All conduit shall be gray schedule 40 electrical grade PVC with galvanized steel sweeping 90-degree elbows.
- Where primary conduit extends above ground level at pole locations, the developer shall use galvanized rigid steel conduit. One 10'0" section shall be attached to the galvanized elbow underground and two additional 10'0" sections shall be supplied to JWEMC for a total of three 10'0" sections per conduit. A grounding bushing shall be supplied for each conduit.
- Where lighting conduit extends above ground level at pole locations, the developer shall attach on 10'0" section of gray schedule 40 electrical grade PVC to the elbow underground and two additional 10'0" sections shall be supplied to JWEMC for a total of three 10'0" sections per conduit.
- Conduit sizes shall be as follows, unless otherwise specified by the JWEMC Engineer:
- single phase primary 2-1/2"
- two or three phase primary 5"
security lights 1"
- 200 amp normal services 2-1/2"
- 400 amp normal services 3"
- secondary (between transformers & pedestals) 3
- All conduits shall be continuous from one elbow to the next, and glued securely so that the conduit will not pull apart when the conductor is pulled through.
- Proper connections between galvanized elbows and PVC conduit shall be installed.
- For each continuous section of conduit, a suitable pull rope/string/wire shall be installed from one elbow to the next and be secured at each end. The pull rope/string/wire shall not be glued to the conduit.
- Each section of conduit shall be blown clean and dry and capped off. This includes elbows to which conduit will be added at a later date.
- Developer/contractor shall be responsible for all conduits until after JWEMC has pulled in all wiring in the project.
- An inspection by the Engineer shall verify that these specifications are met. The developer/contractor shall set up an appointment with the Engineer for an inspection before any conduit is covered. JWEMC reserves the right to require the developer/contractor to excavate portions or all of the installation if necessary to assure conformity.
- No conductor will be pulled prior to passing this visual inspection. This visual inspection is not the final acceptance of the installation. Final acceptance occurs after the conductor is pulled and energized.
- The following diagrams are guide drawings to assist the developer/contractor with the dimensions and manner in which the conduit is to be stubbed up at equipment including: Three-phase transformers vary in size depending on the actual power requirements and will be supplied to the developer/contractor as needed.
Temporary Service Diagrams
Underground temporary service diagram
Overhead temporary service diagram