North American electrical items

North American electrical devices can be fairly different from ones found in other parts of the world. Despite this, American influences are found in some electrical systems elsewhere, such as the rectangular wall boxes, which are used in Australia, Italy, South Korea and some other nations. Breaker panels similar to American ones have also traditionally been used in countries such as Thailand and The Philippines, though both of these countries are nowadays moving towards using DIN rail breakers.

Standard types of light switches

Rating: 15A 125V

The most common styles of light switches found in North America are of a style that's nowadays very uncommon in other parts of the world: they work similarly to toggle switches used in hobby electronics, with a lever that sticks out from the front and is pushed up or down to turn the lights on or off.

They're wired similarly to American power outlets (and thus have the same issues), with the wire needing to be twisted into a circle and then placed around the screw, which is very easy to touch with the front cover removed and thus presents a shock hazard in case it's broken or becomes missing. The faceplate is, however, different from standard outlets, having a very small opening and being held in place with two screws instead of one.

"Decora" light switch

Rating: 15A 277V

In recent years, a different style of light switch has become popular and is the style most commonly used in newer installations. These are called "paddle" or "Decora" switches, as they have a very large surface area which is easier to press and use a rectangular style of face plate, which is also used by Decora-style outlets.

Wiring is done exactly the same as with traditional switches; it's still possible to touch the terminals with the faceplate removed, however the large size of the switch (and the way it's used) means that doing so by accident is definitely harder.

Interestingly, this specific light switch (made by Leviton as part of their Decora line) is rated for use not just on 120V circuits but also 277V ones, which are often used for lighting in industrial or commercial installations using a 480V supply.

Double-pole breaker

This is a double-pole breaker, used on American 240V circuits, in this case a 30A one which is commonly used for dryer circuits. Double-pole breakers are simply just two breakers that trip together, which ensures that both phases have been disconnected. As with most US breakers, the neutral isn't switched and is instead connected to a separate bus bar.

The use of a double-pole breaker is needed as in North America houses are fed with a split-phase 240V supply, which means that there are two line wires both at 120V with respect to earth. Most appliances just use one and a neutral, but high-powered devices such as electric stoves need the full 240V.

Edison socket cartridge fuse

Edison socket fuses were the standard style of fuse in use in North America before breakers became common. They were traditionally made of glass, though newer ones use plastic, in order to see if a fuse was blown as well as to display its rated current.

The major flaw with these styles of fuses was that it was possible to swap the fuse with one of a higher rating, which risks overloading the wires and causing a fire. This was also an issue with the early types of fuses in use in Europe, however they were quickly replaced by the Diazed ones, which use special rings in the base to prevent the wrong fuse from being used.

Later on, the S-style of fuses were introduced, which used a fixed piece in the panel (which was difficult to remove) in order to prevent the incorrect size of fuse from being used. However, these were still fairly uncommon compared to standard fuses, and thus the problem persisted.