Title: Is it 110VAC, 115VAC, 117VAC, 120VAC or 125VAC?
Course: 2016FA-MCO-115-401 > Section: Module 2: Energy

The answers is – Yes.

Most folks will simply refer to their standard “wall electricity” as either 110 or 120. That “wall electricity” is single-phase AC (alternating current) and typically runs somewhere between 110V and 125V (V is for volts). We say “somewhere between” because depending on where you live in the country, where you live relative to the beginning or ending of the circuit that feeds your house and a number of other factors (e.g. transformers, line loss, etc.) your voltage may vary.

Any of the voltages listed in the header may be found on various devices that call for a US household standard electricity supply. Moreover, truth be known that your device (with any of these inputs requested) should work if plugged in to a standard socket (outlet). Therefore, even if your outlet happens to provide 120VAC and you plug in a lamp with an 110VAC bulb you should have no problems providing light.

Below is an example of the typical AC Type B plug (left) and socket (right). Note that the socket is polarized. Polarized means that the hot or line (110VAC source) and the neutral (110VAC return) are different sizes so that a polarized plug will only fit in the socket one-way without the ground. Obviously, it will only fit one way with the ground.

"Domestic AC Type B USA" by Dgilperez, Wikimedia Commons is licensed under CC BY-SA 3.0

As a first side note, the single phase AC should be provided with a frequency of 60 Hz. Moreover, it is 60 Hz, more or less. If you were to put a frequency counter on the line, do not be surprised to see something “close to 60 Hz” if you do not see 60 Hz. There are tolerances in the frequency, just as in the voltage, to allow for this without incident.

As a second side note, in addition to voltage, you also need to pay attention to the amperage (or amps) of the circuit. All devices will draw some amount of current in order to work. Most residential sockets are designed to carry either 15A or 20A (A is for amps). If a device (or devices) draw more current (amps) than the circuit is designed for, the circuit’s protective device (today usually a circuit breaker, in the past usually a fuse) will trip (breaker) or blow (fuse) to protect the circuit from damage by attempting to supply more current than it safely can. The breaker will need to be reset or the fuse replaced before electricity can be restored to the circuit and your devices.