All electric service supplied by the Cooperative is alternating current (A.C.) with a frequency of 60 Hz. (cycles per second) at the nominal voltage and capacity levels indicated below. Single-phase service is readily available in most locations throughout the Cooperative’s service territory, and three-phase service is available in certain locations. However, where single or three-phase service is not presently available, but is required to accommodate a member’s electric needs, service can usually be extended at the member’s expense (see Section 5- Service Extensions).
1. Types of Service Available
- 120/240 volts. 3 wire, single-phase normally up to a maximum requirement of 100 KVA, although higher amounts may be permitted at certain locations, subject to approval by the Cooperative.
- 208Y/120 volts. 4 wire, three-phase up to a maximum of 150 KVA for an overhead service, and no limit for an underground service. Service at 120/208 volts. 3 wire, single phase network service is also available for customers located in an area serviced by 208Y/120 volts three-phase, when the demand for single-phase service is incidental to the requirement for three-phase service.
- 480Y/277 Volts. 4wire, three-phase up to a maximum of 500 KVA for an overhead service, and no limit for an underground service.
- High Voltage Service is available for large industrial customer or other special applications.
2. Voltage Variation
- Equipment Ratings - Member installed equipment should be rated for operation at the designated nominal voltage class offered by the Cooperative. Ratings that deviate from the nominal service classification, such as the use of 240 volt motors on a system nominally rated at 208 volts, may result in inadequate performance, or failure of the equipment.
- Voltage Regulation - Service provided by the Cooperative is subject to reasonable variations in accordance with industry standards and regulatory requirements. In general, under normal conditions, steady state voltage variation at the meter location will be within 5% of the nominal voltage rating of the designated service classification. While the Cooperative cannot guarantee that all members will experience voltage regulation within this range throughout its distribution system, it will endeavor to take remedial action to improve the regulation of its service voltage where sustained variations outside of this range prevail under normal circumstances.
- Automatic Protection - Any equipment which might be adversely affected by infrequent or long term excursions of the service voltage outside of the normal voltage range should be equipped with suitable automatic isolation protection. Due to circumstances beyond the control of the Cooperative, including, but not limited to, instances of equipment malfunction, or voltage variations originating on other interconnected distribution, transmission, or generation systems, the Cooperative cannot provide protection for all conceivable system conditions. The Cooperative recommends that member owned equipment be equipped with protective devices in addition to those required by the National Electric Code to guard against damage caused by the following events:
- Loss of Phase
- Under-voltage or Over-voltage
- Phase Reversal
- Automatic Restart Following an Interruption
- Voltage Drop - An allowance must be made for voltage drop in the customer wiring between the meter location and the terminals of the customer’s equipment. Where a member chooses to install his or her own service extension, the Cooperative strongly advises that such installations adhere to the minimum size and maximum distance specifications described under paragraph #8 of Section 5- Service Extensions.
- Voltage Sensitive Equipment – Certain Types of utilization equipment, such as computers and x-ray machines, may be highly sensitive to transient voltage variations. The Cooperative recommends that members with such equipment install auxiliary devices to filter out transient over-voltages or to regulate service voltages with additional precision.
3. Interruption of Service
The Cooperative is required to furnish "reasonably adequate service". It does not, however, guarantee continuous service, and does not assume direct or indirect liability for loss or damage to persons or property due to its service being furnished to the member’s premises, or as a result of any interruption or variation in the service supplied. Although the Cooperative strives to provide advanced notice of any interruption required to improve or repair the system, it may from time to time interrupt service to a member without notice in order to perform emergency repairs or improvements to its distribution system, or to comply with an order or request of any Federal, State, municipal, or other authority.
4. Short Circuit Duty
The Cooperative’s Engineering Department can provide the calculated short circuit duty at a member’s service location to assist in selecting service entrance equipment of the proper short circuit rating. In most cases, the short circuit current available on a single-phase service to a single residential customer or farm will be less than 10,000 amperes. For commercial, industrial, or multi-unit residential buildings, the available short circuit current will depend on the size of the installation and the location of the Cooperative’s distribution system, and must be calculated independently for each application.