Keep in mind that, while a two-wire circuit may be "legal" in some places, it is not as safe as an electrical circuit (and receptacle) with a grounding conductor. So if you can help it, don't use two-wire outlets everywhere on your property.
Two-wire outlets are common in older homes and other properties where the building code didn't require us to install three-wire outlets. On these circuits, both hot wires go to the outlet, and there's no third path for current to take if one of the wires gets damaged. This can be fine for small things like lamps or kitchen appliances, but not recommended for tools or other equipment that might need a ground connection.
Three-wire outlets are required by law in most areas now. They're usually called "grounded neutral" or "balanced" circuits. They're safe to use anywhere you have power already installed, including old houses. A three-wire circuit allows one side of something - such as a tool - to have its own dedicated ground path if it needs one. This can help prevent shocks if someone trips over a cable or hose lying in the yard for example.
Four-wire circuits are used by electricians to provide extra safety measures against shock hazards.
Let us not, at the the least, make un-grounded and two-wire circuits/electrical outlets even more unsafe by installing the incorrect receptacle type.
The best option for your situation will depend on how many appliances use this outlet, and whether or not they are all being grounded. If you are unsure of what would be best for your situation, contact a licensed electrician who can help determine the safest course of action for your situation.
Some homes only have outlets with two prong receptacles. This is a difficulty for owners of electrical gadgets that use power cables with a third prong for the ground. Although it is unwise and dangerous, many individuals prefer to cut out the third prong on electrical cables and use them in a 2-prong outlet regardless. There are several types of appliances that are designed for use with 2-prong outlets only; they are called "2-prong compatible".
Cords with only two wires contain either red or black with no white. These are usually used for low voltage devices such as lamps, heaters, and air conditioners. Cords with three wires usually have one each of red, black, and green. These are used for high voltage equipment such as stoves, dryers, and dishwashers.
The number of wires in an extension cord should be equal to or greater than the number of wires in the original cord. For example, if the original cord has three wires, then the extension cord should also have at least three wires. If the original cord has two wires, then the extension cord should also have two wires.
Extension cords are essential for anyone who uses multiple appliances without the ability to close off circuits. They allow you to connect a variety of tools and appliances without causing damage to other items on the circuit. Extension cords come in different sizes and shapes depending on the need they are meeting.
Two-wire home wiring can be hazardous since it increases the chance of electric shock. Three-wire electrical circuits reduce the possibility of electric shock. Surge protectors can also be used to keep your electrical equipment safe.
Two-wire systems are most common for small appliances such as refrigerators, air conditioners, heat pumps, and washing machines. These appliances usually have two terminals: one for hot and one for neutral. A three-wire system has all three terminals on one conductor: one for hot, one for neutral, and one for ground. This type of wiring is required by some local authorities who say that it is safer because you cannot get electric current on both hot and neutral wires at the same time.
Two-wire systems are also called single-phase power because there's only one voltage source supplying electricity to these devices. Three-wire systems have two separate voltage sources feeding different parts of the circuit. The danger with three-wire systems is if one appliance fails so does its companion piece of equipment. For example, if the refrigerator stops working so will the freezer, and the people in the house will not be able to use their oven or stove top. This could cause other problems down the road if the person doing the repairs doesn't realize that they are working on a three-wire circuit.