What Is Rule K And What Does It Mean To Me?

Idaho Power’s Rule K, Customer’s Load and Operations Tariff, applies to all Idaho Power customers. It details customer responsibilities and equipment limitations related to power quality and reliability. By meeting Rule K obligations, customers help ensure they receive quality energy services and we can provide power on demand now and in the future.

Rule K Customer Responsibilities And Equipment LimitationsRule K addresses power quality and reliability relating to:

• equipment that may interfere with service to other customers,

• requirements for customers to give notice before making significant changes to their electrical equipment,

• the customer’s responsibility for protection of their own electrical equipment, and

• single-phase service to motors larger than 7½ horsepower.

Rule K also allows Idaho Power to limit the physical effects of harmonics on our system equipment, as well as on customer equipment. Harmonics generally affects large commercial, industrial and irrigation customers.

All harmonic-generating equipment is required to comply with the Institute of Electrical and Electronics Engineers, Inc. (IEEE) Standard 519-1992, “Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems.” This standard has been approved by the public utility commissions in both Idaho and Oregon.

Harmonics occurs when customer electronic equipment produces higher current and voltage frequencies than are safe for Idaho Power’s electrical system. Harmonics has the potential to impact power quality and cause both customer-owned and Idaho Power equipment to fail. Some devices that can cause harmonics include:

Commercial Customers• high-efficiency lighting with electronic ballasts or discharge-type lighting employing magnetic ballasts

• adjustable speed drives for HVAC equipment, elevators, compressors and pumps

• large numbers of electronic single-phase loads such as computers, printers and copiers

Irrigation Customers• variable frequency drives (sometimes called variable speed drives or adjustable speed drives) for pumps, both three-phase and single-phase

CID#49659/900/09-09 © 2009 Idaho Power Printed on recycled paper.

Idaho Power has a responsibility to limit harmonics on its system. Facilities whose equipment causes harmonic voltage distortion are required to use additional filters or other harmonic mitigation equipment to meet Rule K requirements. These are available from your electrical equipment supplier.

Knowing your responsibilities under Rule K will help Idaho Power improve power quality at your location and meet our commitment to provide reliable, responsible energy services, today and tomorrow. For more information go to www.idahopower.com/rulek.