In the United States, the standard household electrical supply is 120V and 240V at a frequency of 60 Hertz. Industrial and commercial electricity supply can often be 3-phase power, using different voltage standards from 208V to 400V. If you’re considering upgrading circuits for your home or garage workshop, the important question is probably 120V vs 240V, and what is the best amps for these outlets. People who have travelled internationally are often curious why the power supply in the US is not the same as Britain, Europe, and most other regions. Japan has the most complicated setup, with two frequencies used.
This article is going to provide a complete understanding of electricity. Having spent most of my life dealing with electricity supply, I’m fascinated by all the complexities involved in optimizing current and the importance of maintaining steady voltage and frequency (voltage vs frequency). This guide to understanding electricity is aimed primarily at helping people understand the power in their home and shops. I will, however, provide many other details and interesting facts. If you live in the US and want to gain a basic understanding of your electrical panel, outlets, and the best way to go about using 120V and 240V, this is where I’ll start. Following this, I’ll go into more technical detail on how electricity works and the fascinating history that led to the electric standards used around the world.
Electrical outlets in North America (and some regions in South America) use the North American Electrical Manufacturers Association (NEMA) standard. There are many types of 120V, 240V, and 120V/240V outlets used in the US. I’m going to talk about the most commonly used receptacles and how they work. Modern electrical regulations require that outlets be grounded. So I won’t be dealing with the 2-prong variants (NEMA 1 & 2) used in older electrical installations. Since most of us are dealing with 120V – 240V power, these will be the most common. NEMA 120V – 240V Receptacles. All NEMA electrical receptacles have the letter “R” at the end.
Yup, you’ve guessed it, this stands for receptacle. Locking outlets, keep the plug locked in position so it remains connected if the cord is pulled.