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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.