Wiring an American Plug

Wiring an American plug is no more difficult than wiring a UK or European plug… but getting hold of them in the UK is much more difficult – and they can be quite expensive! So much so, a full American cord set with moulded connectors (as shown on our Mains Leads page) will cost less than the rewireable plug…

Still, if you want to buy American connectors, why not check out our NEMA5-15P plug, or our NEMA5-15RX extension socket.

Alternatively, if you can’t find what you’re looking for, either take a look at our International Plugs and Sockets page or give us a call: you can find our details here.

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

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 well 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”.

Older examples were asymmetrical and therefore non-polarised, i.e. you could fit the plug in either way, but the neutral insertion point in the modern type A socket is wider to accommodate polarized type A plugs allowing for polarised connectors. Polarised 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 and moulded power leads, are sold with both pins narrow and many rewireable 1-15 compatible connectors are also non-polarised.

NEMA 2-15

The NEMA 2-15 range of connectors have been effectively discontinued for some time. However, if you find yourself faced with one of the these in a repair environment the wiring convention is the same as for the 1-15 range.

NEMA 5-15 / CS22.2, Nº42

The type B mains plug has two flat parallel pins with the same geometry as type A, and a rounded ground or earthing pin, commonly formed from flat metal folded into a ‘U’ shape but in some cases solid pins may be used. The connector is rated at 15 amps 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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