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March 2024
The chart above shows the history of the voltage during the month of March. The average voltage during the month was 123.20 VAC, almost the same as February. The voltage was greater than the nominal 120 VAC about 98.51% of the time, based on 8,907 measurements. Ideally, the voltage should be greater than (and less than) the nominal voltage about 50% of the time. The maximum voltage recorded during the month was 128.8 VAC.
The average voltage during each 5-minute recording period is shown in the chart above by a black line; the maximum voltage recorded during each recording period is shown by a red line, and the minimum voltage is shown by a light blue line. The green line in the chart is the nominal voltage of 120 VAC. Our measurement methodology is explained here.
The histogram above shows the statistical distribution of average voltage measurements for the whole month. You can easily see the preponderance of voltage measurements in excess of the nominal voltage, 120 VAC.
The scatter diagram above shows the voltage measurements according to the time of day when they were taken. The black dots (actually, small crosses) are the average voltage during that 5-minute measuring period, while the red crosses are the maximum voltage during that period, and the light blue crosses are the minimum voltage during that period.
The chart above shows the average of all the voltage measurements at the times of day when the measurements were taken (every 5 minutes). The daily cycle of voltage variation has become almost totally obscured.
See also the archive of voltage measurements at my home for data about other months since December 2015.
Can you measure the voltage at your own home? Compare your results with mine here. Contact me to trade measurements and other details.