Wiring an American Plug

rubber nema 5-15 8520

Wiring an American Plug is no more difficult than wiring a UK or European plug… but over here getting hold of them is much more difficult and they are quite expensive!

So much so, a full American cordset with moulded connectors as shown on our Mains Leads page will cost less than the rewireable plug…

Electricity can KILL!! If you are in any doubt at all about what you are doing, or your ability to do the work, you should refer any mains connection work to a qualified electrician.

NEMA 1-15

Nema 1-15 Mains Plug Wiring 300px
All NEMA 1 devices are two-wire non-grounding connectors rated for 125V maximum. NEMA 1-15P are the two-prong plugs commonly found on household lamps and consumer electronics such as clocks and radios as wekk as on “double-insulated” small appliances. The corresponding sockets have not been allowed in new construction in the United States or Canada since about 1965, but remain in place in many older homes and are still sold “for replacement use only”.Early examples were symmetrical, but later sockets and most newer plugs distinguish the neutral conductor by making it slightly wider than the hot one. Such newer plugs often will not fit in old sockets, but both versions fit in type B sockets. Some devices that meet strict standards, such as sealed electronic power supplies, are still sold with both pins narrow.The neutral insertion point in the modern type A socket is wider to accommodate polarized type A plugs. 

NEMA 5-15 / CS22.2, Nº42

Nema 5-15 Mains Plug Wiring 300px
The type B mains plug has two flat parallel pins with the same geometry as type A, and a round ground or earthing pin. It is rated at 15 amperes and 125 volts maximum. The American standard for this connector is known as NEMA 5-15, and the Canadian standard CSA 22.2, Nº42. The American and Canadian connectors are effectively identical.The ground pin is longer than the two parallel pins so that the device is grounded before the supply is connected. The neutral insertion point in the type B socket is wider to accommodate polarized type A plugs, but the type B plugs often have both pins narrow, the ground pin enforcing polarity.With American and Canadian plugs, if you look directly at a socket, the ground socket will be at a bottom, the live slot is on the right and the neutral slot is on the left. If the plug is polarized, the widest slot is the neutral connector.This view is the same as looking at the solder side or screw side of a rewireable plug, as shown in the diagram to the left.


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