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Home > Contractors & Developers > Customer Service > Meter Specification Manual > Chapter 10

Meter Specification Manual


Chapter 10: Service Impairing Equipment Regulations



"Service impairing" equipment is defined as:
  • Customer electrical equipment (welders, arc furnaces, motors, driving compressors, X-ray, and other equipment) having highly fluctuating or large instantaneous demand, compared to their average demands.
  • Loads which cause harmonic distortion (some large computers and variable speed controllers) or other electrical disturbances.
These unusual variations can impair quality of service to other Customers and must be eliminated or controlled within performance limits determined by OPPD or nationally recognized standards (i.e. ANSI, IEEE, etc), as set forth in OPPD’s Service Regulation D-9 and as follows:
The electricity usage or equipment operations of any Consumer shall not cause electrical disturbances or problems for other Consumers. Such disturbances or problems may include but are not limited to: steady-state voltage excursions beyond recognized limits (ANSI C84.1), transient disturbances, magnetic field interference, stray current/voltage, radio frequency interference, and consumer generated harmonics in excess of recognized limits (IEEE 519-1992). It is the Consumer’s responsibility to take corrective action to comply with all applicable standards or pay the costs incurred by the District to take appropriate corrective action as a result of the electrical disturbance or problem.



The effects of service impairing loads will vary depending on their location in relation to OPPD's electrical supply system and other customers. Each proposed installation must be carefully studied in advance of connection to OPPD's lines. OPPD will determine (from electrical and operating characteristics of the proposed load to be supplied by the Customer or equipment manufacturer, as well as the OPPD electrical supply system) what steps must be taken by the customer and OPPD to prevent impairment of service to other customers.



The customer should install equipment, which causes a minimum of service impairment, or install corrective equipment at the load location.

Where OPPD's electrical supply facilities are reasonably adequate and have capacity to serve normal load additions, the cost of OPPD's additional facilities and/or alterations specifically required to prevent impairment of service to other customers, will be billed to the customer installing service impairing equipment.

Where the service impairing load requires special nonstandard OPPD equipment, the excess cost of such equipment will be billed to the customer installing the load.

If tests, after the equipment is in normal operation, show further additions or alterations of OPPD's electrical supply system are necessary to eliminate service impairment, the cost of such changes will be billed to the customer operating the equipment.



The customer shall consult OPPD and obtain approval before installing transformer type arc welders or furnaces. Such equipment shall conform to the previous  Paragraphs 10.01 to  10.03, and be provided with a nameplate showing:
A.    Manufacturer, type, and serial number.

B.    Frequency.

C.    Primary volts.

D.    Maximum input amperes at rated output.

E.    Output volts at rated output amperes.

F.     Rated output amperes.

G.    Rated duty cycle.

H.    Temperature rise in degrees Celsius.

I.      Open circuit voltage.



Large installations of controls using rectifiers or other devices, which cause waveform distortion (harmonics), may require filtering or isolation, by the customer, to prevent service impairment to other customers.

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Meter Manual

OPPD's Meter Manual contains specifications and drawings. The manual supplies key information to customers, employees, architects, engineers, contractors and others.

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