Determination of average meter error.

69-09-02-27. Determination of average meter error. Whenever a metering installation is found upon any test to be in error by more than two percent at any test load, the average error shall be determined as follows: 1. If the metering installation is used to measure a load which has practically constant characteristics, such as a streetlighting load, the meter shall be tested under similar conditions of load and the accuracy of the meter "as found" shall be considered as the average error. 2. If a single-phase, or direct current, metering installation is used on a varying load, the average error shall be the weighted algebraic average of the error at light load, with a weighting of one, and the error at heavy load, with a weighting of four. 3. If a polyphase metering installation is used on a varying load, the average error shall be the weighted algebraic average of the error at light load (unity power factor) with a weighting of one, the error at heavy load (unity power factor) with a weighting of four, and the error at heavy load (fifty percent lagging power factor) with a weighting of two. General Authority: NDCC 49-02-11 Law Implemented: NDCC 49-02-11