When you install a new electric dryer, you must ensure that the electrical wiring in the wall is of a correct size for the dryer. 240 volt circuits carry twice the voltage of standard household circuits and the 240 volt circuits can carry a much higher load of electrical current. Because the 240 volt circuits carry so much electrical current, if the wires in those circuits are too small for the current, the wires will develop heat.
If the wires become too hot, the heat may cause the circuit breakers to trip or may even lead to the development of an electrical fire in the circuits. In order to avoid these problems, it is essential that the wiring in the circuits of an installation of an electric appliance is of the correct size for that appliance. The chart displays the gauge of wire that should be used in circuits of specific amperage.
Choose the Right Wire for 240 Volt Appliances
For instance, circuits that are used to run dryers have an amperage of 30 amps, but the circuits that run ranges are 50 amps, requiring a thicker wire than that used for the dryer. The same can be said for the wiring of water heaters, air conditioning units and electric vehicles. Each appliance has a specific amperage, and the wire used in the electrical circuit must be able to handle that amperage.
Should the wire not be able to handle that many amps, the wire will heat up and develop resistance. Heat and resistance in the wire are two elements that you must avoid for the electrical circuits of these appliances to remain saftey. Many people make mistakes with the size of the wire.
People often only consider the electrical appliance that will be placed into the circuit and do not consider the distance the electricity must travel. Longer wires have a much higher chance of voltage drops along the circuit. For this reason, if the wire run is to be long, it is recommended to select a wire size that is one gauge larger than the recommendation in the chart.
Using a larger wire will keep the voltage steady at the appliances and ensure they functions correctly. The motors and heating elements for these appliances are all designed to function at a specific voltage and will struggle to perform if that voltage isnt maintained at the appliances. The chart also displays the difference between three-wire circuits versus four-wire circuits that are used for dryers and ranges.
Many older homes have three-wire circuits for appliances because three-wire circuits were legal for homes at the time they were built. Today, four-wire circuits are required for added safety in the home. Four-wire circuits keep the equipment ground wire separate from the neutral wire.
This is important for safety in the home in the case that an individual receives an electric shock while touching an appliance with a metal case that is experiencing a wiring failure. If you are replacing an appliance, you may have to change from a three-wire cord for the appliance to a four-wire cord. The wire gauge chart can help you determine which wire gauge is used with which electrical circuit rating.
The material for the wires is another consideration when installing electrical circuits into a home. Copper is the most common material used for residential 240 volt circuits. Copper is used in these circuits because copper can carry electrical current very efficiently with a small diameter of the wire.
Aluminum is used in some cases for service entrance cables. However, the electrical current carried by aluminum has a larger diameter than copper to carry the same amount of current. Furthermore, it also uses special electrical connectors to prevent the connections from becoming loose over time.
Most residential circuits use copper, however. A circuit breaker of the correct size must also be selected to protect the wires in the circuit. The circuit breaker is used to protect the wire, not the appliance.
Because the circuit breaker is protecting the wire, the circuit breaker cannot have a higher amp rating than the wire. For instance, a 40 amp circuit breaker can be used with 8 gauge wire. However, a breaker with a higher amp rating than the wire could lead to problems.
Should a breaker be installed that can carry more current than the wire, the breaker will not trip if the wire overheats, posing a safety hazard for the home. When you have selected the correct wire gauge for the appliances circuits, you must still ensure that the electrical wires are properly installed into the circuits. For instance, you must properly support the cables along the circuits, the electrical boxes must have enough room for the wires, and you must correctly torque the electrical terminals.
If the electrical terminals are not properly torqued, they can become loose with time. Even with the proper wire gauge, improper installation can create hot spots within the electrical circuit. Finally, you must determine where ground fault circuit interrupter protection is required for the home.
The chart indicates that hot tubs, outdoor electrical receptacles, and pool equipment require ground fault circuit interrupter protection at 240 volts. GFCI circuits provide an additional level of protection to the appliances and circuits in the home. Should the electrical current come into contact with water, a GFCI breaker will trip to protect the home and its occupants.
Correctly selecting the wire gauge for 240 volt circuits requires you to ensure that the conductor is matched to the electrical load of the appliance and the distance of the wire run. By ensuring that the wire is matched to the electrical load, the circuits and appliances will function correctly. If the conductor is not matched to the electrical load, the circuits will experience heat at the electrical load or the circuit breakers will trip.
