Difference Between 220 and 240 Volt Wiring

240 volt cable is very important in residential homes for powering heating and cooling devices as well as appliances that consumes more energy.

In the previous time, they have been known as 220 volt electric circuits, but they are now refer to as 240 volt electric circuits. Over the years in America, there have been the problem of accommodating increase electric loads. In resolving this, the American utilities increase the minimal voltages in order to lower the electric current and the wire size that is being used.

In fact, it is for same reason 110 volts electric circuits are now 120 volts electric circuits. Notwithstanding, people still make use of 110 and 220 volts term in their conversation but in its real sense, they are not in use any longer.

The electric circuits are primarily designed to make use of principals of the electrical phases. For example, double 120 volt electric circuits that are 1800 to each other can be linked together to create one 240 volt electric circuit. This will yield twice the quantity of electrical power with the same wire size. There are two major types of 240 volt electric circuits and they are classified based on the device you are supplying power to. Each type of the 240 electric circuits has a slight difference that makes them to operate differently. Having in depth knowledge of these variances will help you to know the suitable type of cable to use when fixing a device or a new cooling/heating systems.

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3-Wire 240 Volt Cable

Nearly all the contemporary appliances that are common function off 120 volt cable and electric circuits. Connecting this equipment requires the use of three wires. The blue or black wire (also known as the hot wire) is the one that conduct electric current to the device. The white wire is usually neutral and it is used to perfect the circuit. It can be outlined back to the electric panel where it is joined to the neutral bus. The green wire or sometimes naked copper wire is the earth wire and it is used for electric safety.

In some cases in 240 volt cable, there may be no need for the neutral wire; instead an extra hot wire may be included. The two hot cables will now complete the circuit. In order to safely account for the two leads, the wire must be joined to a two – pole breaker at the electric circuit panel. In other word, a two single – pole breakers that have been wired together is known as a two – pole breaker. 240 volt circuit that contains this form of wiring is popularly used in electric heaters, boilers, or condensing units as a source of power. Appliances that belongs to this group does not require 120 volt circuit.

4-Wire 240 Volt Cable

The second type of 240 volt circuit is commonly used for appliances such as dryers and electric stoves. Though this device make use of 240 volts to control their main function, it can also make use of 120 volts to control equipment such as clocks and timers.

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It is like a 3 – wire 240 volt cable, the notable difference is that a white or neutral wire is included with other wires to perfect the circuit for equipment or devices that make use 120 volt circuit. Just like other types of wire, a bare copper or green wire is also included as the earth wire. A 4 – wire 240 volt cable, just like 3 – wire 240 volts, will require fitting two – pole breaker in the circuit panel.

Changes to the National Electrical Code (NEC) now require that this type of electric wiring should be used predominantly in residential home construction. That is why most of today’s dryers and oven ranges come equipped with a 4-prong plug.

How to wire 220 – 240 Volt NEMA 6-50

David Finch
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  • Voltech 08.02.2017 at 23:54

    Had a guy ask me what differences are between the 3 208/220/240. As I started to answer him, I realized I could not answer him with an answer that was understandable for a green guy. Anyone have an easy answer for this, or maybe a good read explaining it?


    • Romex Butcher 08.02.2017 at 23:56

      “220” and “240” are the same thing. “220” is what the unqualified use to describe 240 volt circuits.

      208 can only be obtained from a 3-phase wye system. 240 volts can be obtained from either a 120/240 residential system or a 240 volt 3-phase delta system. Delta systems are quite rare nowadays, at least in my area where the poco has long since phased them out (pun intended.)

  • cleveland 08.02.2017 at 23:38

    I’m installing a 30 amp, 240 volt, single phase, stationary air compressor. I’ve read that this is a confusing issue and in the states they’re one and the same in regards to voltage requirements and you can be above or below a voltage requirement for a compressor or other high voltage appliance requirements by 10%.

    I plan on using an existing 30 amp breaker in the box formerly used for an electric stove. I also have a 50 amp breaker in the box that is not being used if this would be a better option. Also, after running the wiring near the compressor, I plan on installing a separate box next to the breaker with a slow blow, 30 amp fuse dedicated for just the compressor.

    Is a 220 volt and a 240 volt power requirement one and the same and should I use the 30 or the 50 amp breaker?

    Any help would be greatly appreciated.

    • jbfan 08.02.2017 at 23:51

      Use the name plate of the compressor for the breaker size.

      A 30 amp breaker requires #10 wire and a 50 amp breaker requires #6 wire.

      240 volt is todays standard, while 220 was used in the past.
      They are interchangable.

    • Home Improvementer 08.02.2017 at 23:52

      >240 volt is todays standard, while 220 was used in the past.

      Exacly about this we told in article.