Most people don’t spend a lot of time thinking about electrical plugs and receptacles. They take it for granted that just about any power cord will end in a plug that fits neatly into that socket it the wall.

But the pros know that there are more configurations for plugs and receptacles than the average person ever dreams of, with blades of many sizes and shapes. That’s because, once you get beyond the requirements of simple household appliances, you’ll need circuits that deliver more power with higher amperages, voltages or both.

And while these circuits are perfect for welding machines and other industrial equipment, you wouldn't want to plug something into them that wasn’t designed to handle their voltage and amperage.

Fortunately, there’s a set of standards developed by the National Electronics Manufacturers Association (NEMA) that specifies which plug and receptacle configurations can be used with which amperages and voltages. These standards, ANSI/NEMA WD 6-2021, are designed to prevent “unsafe interchangeability” by making it physically impossible to plug a device into a receptacle that has the wrong kind of power for it.

These charts show many of the possible NEMA configurations, from the common wall socket to more rarely seen plugs and receptacles.

NEMA Straight-Blade Plug and Receptacle Configurations

Classic straight-blade NEMA configurations are quick to plug in and unplug.

Two-Pole, Two-Wire

NEMA Number	Voltage	Amperage	Configuration	Application Notes
1	125V	15		1-15 plugs and receptacles • Old wall outlets • Some small appliance plugs
2	250V	20		2-20 plugs and receptacles

Two-Pole, Three-Wire, Grounding

NEMA Number	Voltage	Amperage	Configuration	Application Notes
5	125V	15		5-15 plugs and receptacles • Wall outlets and most household appliances
		20		5-20 plugs and receptacles
		30		5-30 plugs and receptacles
		50		5-50 plugs and receptacles
6	250V	15		6-15 plugs and receptacles • Air conditioners
		20		6-20 plugs and receptacles • Air conditioners, power tools
		30		6-30 plugs and receptacles • Air conditioners
		50		6-50 plugs and receptacles • Some EV chargers
7	277V	15		7-15 plugs and receptacles • Some high-powered lighting
TT	125V AC	30		TT-30 plugs and receptacles • RVs and trailers

Three-Pole, Three-Wire

NEMA 10 has been deprecated for new installations since the National Electrical Code (NEC) of 1996. NEMA 14 plugs and receptacles are comparable but with the addition of a ground connection.

NEMA Number	Voltage	Amperage	Configuration	Application Notes
10	125 / 250V	20		10-20 plugs and receptacles • Clothes dryers and kitchen ranges
		30		10-30 plugs and receptacles • Clothes dryers and kitchen ranges
		50		10-50 plugs and receptacles • Clothes dryers and kitchen ranges

Three-Pole, Four-Wire, Grounding

NEMA Number	Voltage	Amperage	Configuration	Application Notes
14	125 / 250V	20		14-20 plugs and receptacles
		30		14-30 plugs and receptacles • Clothes dryers, some EV chargers
		50		14-50 plugs and receptacles • Ovens, some EV chargers, RVs, portable generators, commercial audio and lighting
		60		14-60 plugs and receptacles
15	3 Ø 250V	20		15-20 plugs and receptacles
		30		15-30 plugs and receptacles
		50		15-50 plugs and receptacles
		60		15-60 plugs and receptacles

Four-Pole, Four-Wire

NEMA Number	Voltage	Amperage	Configuration	Application Notes
18	3 Ø Y 120 / 208V	20		18-20 plugs and receptacles
18	3 Ø Y 120 / 208V	50		18-50 plugs and receptacles
18	3 Ø Y 120 / 208V	60		18-60 plugs and receptacles

NEMA Locking-Blade Plug and Receptacle Configurations

Twisting a locking-blade plug after inserting it into its receptacle creates a secure connection that prevents unintentional unplugging in commercial and industrial settings.

Two-Pole, Two-Wire

NEMA Number	Voltage	Amperage	Configuration	Application Notes
L1	125V	15		L1-15 plugs and receptacles
L2	250V	20		L2-20 plugs and receptacles

Two-Pole, Three-Wire, Grounding

NEMA Number	Voltage	Amperage	Configuration	Application Notes
L5	125V	15		L5-15 plugs and receptacles
		20		L5-20 plugs and receptacles
		30		L5-30 plugs and receptacles • Docked boats and RVs
L6	250V	15		L6-15 plugs and receptacles
		20		L6-20 plugs and receptacles • Welders and plasma cutters
		30		L6-30 plugs and receptacles • Welders and plasma cutters
L7	277V AC	15		L7-15 plugs and receptacles
		20		L7-20 plugs and receptacles
		30		L7-30 plugs and receptacles
L8	480V AC	20		L8-20 plugs and receptacles
		30		L8-30 plugs and receptacles
L9	600V AC	20		L9-20 plugs and receptacles
		30		L9-30 plugs and receptacles

Three-Pole, Three-Wire

NEMA Number	Voltage	Amperage	Configuration	Applcation Notes
L11	3 Ø 250V	15		L11-15 plugs and receptacles
		30		L11-30 plugs and receptacles

Three-Pole, Four-Wire, Grounding

NEMA Number	Voltage	Amperage	Configuration	Application Notes
L14	125 / 250V	20		L14-20 plugs and receptacles
		30		L14-30 plugs and receptacles • Backup generators
L15	3 Ø 250V	20		L15-20 plugs and receptacles
		30		L15-30 plugs and receptacles
L16	3 Ø 277 / 480V	20		L16-20 plugs and receptacles
		30		L16-30 plugs and receptacles
L17	3 Ø 600V	30		L17-30 plugs and receptacles

Four-Pole, Four-Wire

NEMA Number	Voltage	Amperage	Configuration	Application Notes
L18	3 Ø Y 120 / 208V	20		L18-20 plugs and receptacles
		30		L18-30 plugs and receptacles
L19	3 Ø Y 277 / 480V	20		L19-20 plugs and receptacles
		30		L19-30 plugs and receptacles

Four-Pole, Five-Wire, Grounding

NEMA Number	Voltage	Amperage	Configuration	Application Notes
L21	3 Ø Y 120 / 208V	20		L21-20 plugs and receptacles
		30		L21-30 plugs and receptacles
L22	3 Ø Y 277 / 480V	20		L22-20 plugs and receptacles
		30		L22-30 plugs and receptacles
L23	3 Ø 347 / 600V	20		L23-20 plugs and receptacles

Midget Locking

NEMA Number	Voltage	Amperage	Configuration	Application Notes
ML1 (two-pole, two-wire)	125V	15		ML1-15 plugs and receptacles
ML2 (two-pole, three-wire, grounding)	125V	15		ML2-15 plugs and receptacles
ML3 (three-pole, three-wire)	125 / 250V	15		ML3-15 plugs and receptacles