Warm Outlet After Vacuum Use

Electrical Heating

• Electricity encounters resistance as it passes through a conductor. The more resistance it encounters, the more heat it produces. Good conductors of electricity have less resistance than poor conductors, but still exhibit some resistance. The amount of heat generated depends on the amount of electricity passing through the conductor and the size of the conductor. A large conductor has less resistance than a small one, so less electricity is converted to heat. A large electrical current generates more heat than a small current.

Vacuum Cleaner Current

• Most home vacuum cleaners draw a maximum of 12 to 13 amperes of current. The typical home electrical outlet supplies up to 15 amperes of current, because the circuit breaker or fuse that protects the wiring won't allow more than 15 amperes to pass through the wires. This protects the wires from overheating and possibly starting a fire.

  At 10 to 13 amperes, the wiring or outlet might get warn, particularly if the vacuum cleaner is operated for long period of time. However, a wire that makes poor contact with the outlet terminal could cause a higher resistance and make the wire or outlet hot.

Aluminum Wiring

• Aluminum wiring replaced copper wiring for a short period of time in the late 1960s. Aluminum expands and contracts more than copper as it heats and cools. This causes the wire to loosen on terminals, which causes more resistance and greater heat, sometimes enough to cause a fire. Aluminum also oxidizes, another factor that contributes to resistance and overheating. An outlet wired incorrectly with aluminum wire may overheat under the load placed on it by a vacuum cleaner. If your home was built in the late 1960s or early 1970s, have it inspected for aluminum wiring.

Wiring and Outlet Rating

• The National Electrical Code states the minimum-size wire for a 15-ampere circuit is 14-gauge wire and requires an outlet rating of at least 15 amperes. Smaller wires or outlets rated lower than 15 amperes will overheat and possibly cause a fire. If your outlet is hot and not just warm, or the wall is warm near the outlet, have the wiring inspected for problems. Old, worn outlets can get warm, and replacement is inexpensive insurance.