Common NEMA Power Plugs Used for Lighting Fixtures

We're often asked for help in identifying the types of power plugs used on lighting fixtures in commercial and industrial facilities. It may seem like there's no rhyme or reason behind these strange power plugs, but they were created to reduce the risk of accidents and to ensure proper power connections for electrical equipment. In this article, we'll discuss the most common NEMA power plugs that are used to connect lighting fixtures to plug-in receptacles. The power plugs we'll discuss here are all covered by the ANSI/NEMA WD-6 standard set by the National Electrical Manufacturers Association. NEMA wiring devices are made in current ratings from 15 to 60 amps, and voltage ratings from 125 to 600 volts. The standard defines different combinations of blade widths, shapes and orientations to create unique plug configurations for specific voltage, current, and grounding systems. These plugs and sockets ensure that equipment requiring a specific voltage/current/grounding configuration are not plugged into the wrong electrical system. For lighting, we will focus on 15 and 20 amp plugs in both straight-blade and twist-lock varieties.

NEMA Power Plugs Chart

NEMA Classification	Receptacle	Plug	Voltage Rating	Current Rating	Notes
NEMA 5-15			125V	15A	The NEMA 5-15 plug is the standard grounded straight-blade plug used throughout North America, Canada and parts of Mexico. Typically used in 120V lighting systems.
NEMA L5-15			125V	15A	This is the twist-lock version of the 120V plug. Twist-lock plugs are more common in industrial applications that may be subject to vibration or to prevent inadvertent disconnects.
NEMA L7-15			277V	15A	The NEMA L7-15 plug is the most common twist-lock plug used on 277V lighting systems.
NEMA L7-20			277V	20A	Some 277V lighting systems may use the NEMA L7-20 plug. The easy way to tell the difference is by looking at the direction of the locking ground tab. The 20A points outward while the 15A points toward the center.

Identifying Your Plug

The easiest way to identify what plug or socket you have is by looking directly at it and comparing it with the images above. If you're trying to identify the plug, compare with the images in the Plug column above. The plug will have the straight or curved blades protruding from the plug body and is considered the male end of the connection, while the socket or receptacle will have corresponding slots and is considered the female end of the connection. If you can't identify your plug from the chart above, contact us and we'll be glad to help.