The 2 240 volt lines coming into your house are they 240V Peak which would be 220V RMS or is 240 the RMS Value

Question

Im confused because lots of people say 220V and some say 240V are these the same just one persons saying the rms and the other is saying the peak

Answer 1

No, they are both RMS values. The difference is in the fact that power companies don't regulate voltage precisely, and the RMS voltage can vary anywhere from 210 to 250 depending on where your house is located in the grid and how much power is being consumed in your neighborhood and how old the power lines and transformers are. Sometimes, the voltage can drop as low as half the expected value, and that's called a brownout.

Most of the time, appliance manufacturers assume that the RMS voltage will be 220 (thus the peak voltage will be 311), but they also allow for variations higher or lower in their design.

Answer 2

Power company residential transformers are wound for 240 volts on the secondary terminals (the customer side). When installed, the power company will always, or should always, adjust the taps until the output is 240 volts. Since the primary side of the transformer is usually at least 12780 volts, voltage drop is rarely an issue. I have designed power grid circuits and these circuits are designed to only have a 3 percent voltage drop to the transformer. The transformers have tap adjustments to boost back up to 240 volts if there is a significant voltage drop. The reason people say 220 is because that is an old voltage system. A lot of appliances will be rated for 220 volts, but will operate fine at 240 volts. The point is, if you meter the voltage at your meter, chances are, you will get a read of 240 volts plus or minus a few volts. This is a perfect scenario. As dogwood stated above, high demand on the power grid affects voltage that you will actually get at your meter.

Voltage is carried on a sine wave. RMS (root mean symmetry) is an average measurement of the voltage sine because it is constantly shifting from a high positive value to a high negative value (alternating).

Answer 3

240 RMS
The peak would be 340 and the peak to peak would be 680.
Pretty high, huh?

The 120 is RMS too.
Peak is 170 and peak to peak is 340.