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NEMA connectors are named following an alphanumeric code consisting of: prefix "L" (locking types), numerals, a hyphen, numerals, suffix "R" or "P" for "receptacle" or "plug". Neither NEMA nor the US National Electrical Code nor the Canadian Electrical Code specify a preferred orientation, but the National Electrical Contractors Association's National Electrical Installation Standards (NECA 130-2010) specify that the preferred location of the ground is on top. Replacement of obsolete NEMA 1 receptacles requires either rewiring with an additional ground conductor for a NEMA 5 receptacle, or a NEMA 5 receptacle complete with a ground fault circuit interrupter for two-wire non-grounded configurations (when a ground conductor is not available). All descriptions below assume this orientation (i.e., clockwise order is ground, neutral, hot for 120 V receptacle versions; and counter-clockwise for plug versions). There are some obsolete 1-15R or 1-20R (120 V, 15 or 20 A) receptacles which are mechanically able to accept 1-15P (120 V), 1-20P (120 V), 2-15P (240 V), or 2-20P (240 V) plugs. NEMA standards exist for 1-15P, 1-20P and 1-30P plugs, and the 1-15R receptacle. There are no 1-20R and 1-30R receptacles, because 1-20P and 1-30P can mate with a corresponding NEMA 5 receptacle.

NEMA wall receptacles can be found installed in any orientation. There are two basic classifications of NEMA connectors: straight-blade and locking. On August 30, 1999, the plant was sold to Sanmina SCI Systems, Inc. which operated it as a circuit board manufacturing plant for two years until it shut its doors finally in November 2002 putting 850 people out of work. What had been the accepted norms for the industry for sometimes, 80 years, have suddenly been thrown out and replaced by fundamental changes in design, manufacture and operation. KODAK BROWNIE No. 3, Model B - 1911. The Model B came out in 1911, but the one shown above is of 1920 or later since 1920 was the year when the trigger guard was added around the shutter lever. It came in two variatons: the cherry and brass model shown above, and a less expensive model of light mahogany color with nickel plated steel parts. A twisted pair has two wires of a cable twisted around each other. The Metal Clad Cable is an affordable and flexible option for a wide variety of electrical uses.

Cable Bay and Mudbrick vineyards are also just a short drive away. These receptacles are typically found in older residential buildings and are not allowed to be installed under current NEC codes. The current revision of the standard allows optional shutters similar to those of BS 1363. Current UK wiring regulations require socket outlets installed in homes to be shuttered. The Plugs and Sockets, etc. (Safety) Regulations 1994 permit domestic appliances fitted with non-BS 1363 plugs to be supplied in the UK with conversion plugs fitted, what is electric cable but not with conversion plugs supplied for fitting by the consumer. This safety measure reduces shock hazards to a child that attempts to insert a single conductive object into the receptacle. Newer NEMA 1-15 plugs with wider protective faces (middle right) have a safety advantage; plugs for electric toys (right) as well as very early plugs (left) have noticeably wide faces to discourage touching the electrical contacts. All NEMA 2 devices are two-wire non-grounding devices (hot-hot) rated for 250 V maximum. As an example, the 5-15R is the common 125 V two-pole, three-wire receptacle rated for 15 A. The L5-15R, while sharing the same electrical rating, is a locking design that is not physically compatible with the straight-blade 5-15 design.

All NEMA 1 devices are two-wire non-grounding devices (hot-neutral) rated for 125 V maximum. Identically to the NEMA 3 series, this is "reserved for future configurations" and no designs for this series exist and no devices have been manufactured. Ungrounded NEMA 1 plugs are still popularly used by manufacturers of small appliances and electronic devices because of the design's low cost and compact size, and they are upward compatible with modern grounded NEMA 5 receptacles. Standards permit ungrounded plugs where the appliance does not require grounding due to low risk of leakage current, such as on double-insulated devices. This "2-prong" design, with two flat parallel non-coplanar blades and slots, is used in most of North America and on the east coast of South America on lamps; consumer electronics such as clocks, radios, and battery chargers; and other double-insulated small appliances that do not require grounding (earthing). 1-15P plugs have two parallel flat blades, 1⁄4 inch (6.4 mm) wide, 0.06 inches (1.5 mm) thick, 5⁄8-23⁄32 inch (15.9-18.3 mm) long, and spaced 1⁄2 inch (12.7 mm) apart. Single-phase connectors have only a single terminal identified as 'X' or two terminals, 'X' and 'Y'. These connector families have been designed so that connectors of differing types cannot be accidentally intermated.