Electric Service & Meter Installation Guide
Distribution Service at Secondary Voltage
Service From Overhead Lines
The Member will provide a suitable point of attachment adequate to properly support the service conductors and high enough to allow the Cooperative to maintain proper clearance. The service attachment shall be located on the exterior of the building at a point as near as practicable to the point of connection to MVEC’s lines.By mutual agreement the Member will provide a suitable location on his premises for the installation of MVEC’s meter and other equipment. It is recommended that service entrance equipment be of the outdoor type and mounted adjacent to the meter enclosure. (Refer to drawing for Overhead Meter page 34).
The Cooperative usually installs service knobs with screw fastenings on wooden structures (or pipe strap where mast is used) for service drop attachment See drawings or sketches for more detail. The Member will be responsible for installing suitable service wire attachment provisions.
Service Entrance
Mast of minimum 2″ rigid steel conduit may be used on low roof structures to obtain proper ground clearance service drops. Other generally acceptable masts can be 2½” x 3/8″ or 3″ x ¼” angle iron. (Refer to drawing for Service Entrance Mast, page 24).The service entrance shall be exposed conduits, raceway, or approved cable. Fittings with removable covers should be avoided when possible. If these fittings are necessary, the covers should be exposed and sealable.
Service Entrance Conductors
Adequate length of conductor shall be provided for connection of service entrance conductors at the weatherhead, minimum of 18″ required.Service entrance conductors and service entrance equipment is owned, installed, and maintained by the Member.
Residential Service Entrance
The Cooperative recommends a minimum capacity of 150 amperes at 120/240 volts, 3 wire 1ø for residences.
Clearances
All clearance requirements as dictated by code or regulatory bodies must be maintained.
Grounding
The grounded conductor of secondary circuits up to and including 480 volts between conductors must be identified.
- Single-Phase - 120/240 Volt, 3-Wire:The identified neutral conductor.
- Three-Phase - 240 or 480 Volt, 3-Wire Delta:Any phase wire or wire as designated by a Cooperative representative. Three phase, 240 volt and 480 volt, 3-wire will have one corner of the delta grounded unless the Member requests in writing that the system be ungrounded. A fourth wire is required and shall be grounded as an equipment ground.
- Three-Phase - 120/208 or 277/480 Volt, 4-Wire Wye:The identified neutral conductor common to all phases.
- Three-Phase - 120/240 Volt, 4-Wire Delta:The identified neutral conductor of the single phase portion.
Service Installations
Listed below and referenced to a particular drawing are overhead and underground single phase and overhead and underground three phase systems that show wiring configurations and nominal base dimensions:
- Overhead Single-Phase Meter Base
120/240 Volt.………………………………………..Page 38 - Underground Single-Phase Meter Base
120/240 Volt……….………………………………..Page 39 - Overhead Three-Wire Three-Phase Meter Base
240 or 480 Volt….…………………………………..Page 40 - Underground Three-Wire Three-Phase Meter Base
240 or 480 Volt………………………………………Page 41 - Overhead Four-Wire Three-Phase Meter Base
120/240 Volt Delta
120/208 Volt Wye
277/480 Volt Wye.…..………………………………Page 42 - Underground Four-Wire Three-Phase Meter Base
120/240 Volt Delta
120/208 Volt Wye
277/480 Volt Wye ……..…………………………….Page 43
