NEMA Connectors

NEMA connectors are AC power plugs and receptacles used for mains electricity in North America and other countries that use the standards set by the U.S. National Electrical Manufacturers Association (NEMA).

NEMA wiring devices are made in current ratings from 15 to 60 amperes, and electrical potential (voltage) ratings from 125 to 600 volts. Different combinations of contact blade widths, shapes, orientation, and dimensions give non-interchangeable connectors that are unique to a particular voltage, current capacity, and grounding system. NEMA 1 (two prong) and NEMA 5 (three prong) are used for commonplace domestic equipment; the others are for heavy duty or special purposes.

There are two basic classifications of NEMA device: straight-blade and locking. The straight-blade 5–15 and 5–20 are found nearly everywhere in countries using the NEMA standards, and are intended for supplying lighter-duty, general-purpose electrical devices. Twist-locking types are used for heavy industrial and commercial equipment, where increased protection against accidental disconnection is required. Numbers prefixed by L are curved-blade, twist-locking connectors; others are straight blade and non-locking.