page_title: History of AC power plugs and sockets
section_title: US perpendicular socket
hierarchical_section_title: History of AC power plugs and sockets / Obsolete types / US perpendicular socket
caption_attribution_description: English: NEMA 2-20 Author = Robert Casey
context_page_description: Plugs and sockets for portable appliances started becoming available in the 1880s. A proliferation of types developed to address the issues of convenience and protection from electric shock. Today there are approximately 20 types in common use around the world, and many obsolete socket types are still found in older buildings.
context_section_description: Another obsolete socket, made by Bryant, 125 V 15 A and 250 V 10 A rating. A NEMA 5‐20 125 V 20 A or 6‐20 250 V 20 A plug with a missing earth pin would fit this socket, but a NEMA 2‐20 plug is slightly too big to fit.
  The upper slots as seen in the illustration connect to silver-coloured wiring screws on the upper side, and the lower slots connect to brass-coloured wiring screws on the lower side.
  In Australia, the same or similar T-configuration sockets are used for DC power sockets, such as in stand-alone power systems (SAPS), on boats and in police vehicles. Polarity is inconsistent.
  In the former Soviet Union this socket was and still is commonly used for wiring in places where the voltage is lowered for safety purposes, like in schools, filling stations or in wet areas, and is rated 42 V at 10 A AC. Such an unusual connection is intended specifically to make the connection of standard higher-voltage equipment impossible.
caption: Perpendicular slot duplex socket
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