In the early days of electrification, residential use was almost exclusively for illumination, with rooms normally having just a single electrical outlet spot in the center. Along with his … See more

Twist-locking connectors were first invented by Harvey Hubbell III in 1938 and "Twist-Lock" remains a registered trademark of See more

The color of a device neither identifies its voltage class nor power system. Because the colors are not specified by NEMA standards, the purpose of color-coding a receptacle may be set … See more

NEMA connectors are named following an alphanumeric code consisting of:
(prefix L for locking) numerals – numerals (suffix R for … See more

NEMA non-locking connectors all use blades of various flat and folded shapes (except for the round pins used on grounding connectors). The plugs can be detached from the … See more

Over time, electrical codes in the US and Canada began to require additional safety features in the basic NEMA 5-15R and 5-20R configurations to address specific electric shock hazard concerns. The safety features listed below are not mutually exclusive; for … See more

Most duplex receptacles have metal tabs connecting the top and bottom receptacles. These tabs can be broken off to allow the top and … See more