Editing AC power plugs and sockets (section)

==== NEMA 1-15 ungrounded (Type A) <span class="anchor" id="Type A"></span> ====
[[File:NEMA-1 plug polarized.agr.jpg|NEMA&nbsp;1-15 polarised plug|thumb|upright=0.9]]
[[File:A plug.jpg|NEMA&nbsp;1-15 unpolarised plug|thumb|upright=0.9]]
NEMA-1 plugs have two parallel blades and are rated 15&nbsp;A at 125&nbsp;volts. They provide no ground connection but will fit into a grounding NEMA&nbsp;5-15 receptacle. Early versions were not polarised, but most plugs are polarised today via a wider neutral blade. (Unpolarised [[AC adapter|AC&nbsp;adaptor]]s are a common exception.)

[[Harvey Hubbell]] patented a parallel blade plug in 1913, where the blades were equal width ({{US patent|1064833}}). In 1916 Hubbell received a patent for a polarised version where one blade was both longer and wider than the other ({{US patent|1180648}}), in the polarised version of NEMA&nbsp;1-15, introduced in the 1950s, both blades are the same length, only the width varies.

Ungrounded NEMA-1 outlets are not permitted in new construction in the [[United States]] and [[Canada]], but can still be found in older buildings.