Types of Plugs

Types of Plugs

Plugs go hand in hand with outlets. You are likely surrounded by electronics that have a plug or, through a different device like a phone charger, are powered by a plug. The types of plugs used in the US are called NEMA connectors. NEMA stands for the US National Electrical Manufacturers Association, a group formed in 1926 that began publishing standards for how plugs and outlets should be made. This was not a regulatory agency, it was just an agreement between manufacturers to create their own standards. 

The three types of NEMA connectors that you’ll commonly find and use with the 15 amp outlet are the non-polarized (1-15R), the polarized (1-15P), and the grounded (5-15P). A non-polarized connector does not care which way it is connected to the outlet. Polarized plugs, on the other hand, have a wider blade or prong that fits into the left/neutral of the outlet. This means that when plugged in, the electricity enters your plug through the hot side and then exits through the neutral side to complete the circuit. This is a safety feature because the switch for the device can always be connected to the hot side of the outlet. Finally, grounded plugs provide a path for stray electrical current to return safely to the power source, preventing electric shock and potential damage to equipment or devices

Above, NEMA 1-15R (bottom), 1-15P (top right), and NEMA 5-15P (top left)

Below is a short video showing how these different electrical connectors interact with our outlet.