240 Volt Outlet

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You’ve seen those big clunky outlets with the funny angled places to receive the plug prongs. You’ve noticed them behind your clothes dryer and electric range and beside your water heater and air conditioner. Each of these outlets is a 240 volt outlet designed to supply more electrical power for your larger appliances through the 240 volt wiring and 240v single phase plug. These are also quite different from the standard 120v outlets, having more wires, higher voltage, and greater hazards and safety risks. You may have noticed them, but probably never gave them another thought .

until you saw smoke coming from behind your dryer, that is. A little understanding of the 240 volt outlet, 240v single phase plug, and 240 volt plug wiring will help you to be prepared if a problem or emergency does arise. And knowing a reliable emergency electrician in advance is recommended as well.

240 Volt Outlets and Plugs

You’re probably familiar with the standard and more common 120v outlet (sometimes known as 110v) that you plug your phone charger, TV, computer, toaster, vacuum cleaner, and coffeemaker into. Delivering higher voltage and more power and having more wires, 240v outlets are a little different. Basically, two 120v circuits 180 degrees out of phase are connected together, hence the 240 volts, for twice the electrical power without the need for increasing wire size. So your 240v receptacles have two 120v wires supplying power along with a neutral wire.

240v Wires

(Newer homes with newer 240 volt plug wiring will have outlets and plugs with four wires, which includes a ground for greater safety and reduced fire hazard.) Larger appliances, especially those equipped with an electric motor, simply run more efficiently with a 240 volt power supply. These appliances include ovens and ranges, dryers, water heaters, air conditioners, furnaces, and welders. The outlets and plugs for 120v appliances have, as we mentioned, three wires, but only one of these is “hot” – that is, actually carrying electric current – and is usually blue or black in color.

And the white wire, the neutral, completes the circuit, with the green or bare wire simply being a ground. But 240 volt plug wiring has instead of a white neutral wire an additional “hot” that is usually red or blue. These two “hot” wires deliver the 120 volts twice for a total of 240 volts.

These wires are then connected to a two-pole breaker at the circuit panel in your breaker box – basically just two 120v single-pole breakers wired together. This is more complicated than 120v wiring and is best left to the professionals.

The outlets and plugs themselves are larger than 120v ones and have at least three (sometimes four) differently shaped holes and prongs.