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 straight-blade 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
		50		18-50 plugs and receptacles
		60		18-60 plugs and receptacles