NEMA Nomenclature
PDF—Download NEMA Nomenclature Guide
The NEMA (National Electrical Manufacturers Association) pattern and numbering system is made up of four main identifiers. The first identifier can be a blank space or have the letter L. This determines whether it is a straight or locking blade device. The second identifier is a number. The first number in a NEMA listing determines the voltage rating. The third identifier is a number and identifies the amperage rating of the device. The fourth identifier is a letter. This identifier determines whether the device is a plug, P, or a receptacle/outlet, R.The North American Non-locking NEMA Configuration chart will help you determine the correct NEMA configuration for your North American applications.
| N | E | M | A | x | 5 | 15 | P |
| P | indicates plug or receptacle | |
| P | is plug | |
| R | is receptacle or socket | |
| 15 | indicates the current rating and standard values are: | |
| 15 | amps | |
| 20 | amps | |
| 30 | amps | |
| 5 | indicates the voltage | |
| 1 | indicates 125 VAC, ungrounded for Class II connections | |
| 2 | indicates 250 VAC, ungrounded for Class II connections | |
| 5 | indicates 125 VAC, grounded for Class I connections | |
| 6 | indicates 250 VAC, grounded for Class I connections | |
| 7 | indicates 277 VAC, grounded for Class I connections | |
| 8 | indicates 480 VAC, grounded for Class I connections | |
| 9 | indicates 600 VAC, grounded for Class I connections | |
| 14 | indicates 125/250 VAC, single-phase, four-wire, three-pole | |
| 15 | indicates 250 VAC, three-phase, four-wire, three-pole | |
| 16 | indicates 480 VAC, three-phase, four-wire, three-pole | |
| 17 | indicates 600 VAC, three-phase, four-wire, three-pole | |
| 21 | indicates 120/208 VAC, three phase, five wire, four pole | |
| 22 | indicates 277/480 VAC, three-phase, five-wire, four-pole | |
| 23 | indicates 347/600 VAC, three-phase, five-wire, four-pole | |
| x | is the position occupied by L for locking devices. If no letter is present, device is non-locking, straight blade. | |