5 Common Electrical Wiring Mistakes

August 20, 2013 by Valerie Griffiths

Taking care of some home wiring yourself? Be cautious – common electrical wiring mistakes can result in injury or even fire.

Here are 5 common wiring mistakes to avoid (or correct, with the help of an electrician!):

Overloading leads to overheating of circuit components (including wires) and may cause a fire. Credit: OSHAcademy Occupational Safety and Health Training

Overloading leads to overheating of circuit components (including wires) and may cause a fire. Credit: OSHAcademy Occupational Safety and Health Training

1. Circuit Overload

PROBLEM: Is a circuit tripping whenever you run two appliances at once? You’re giving it more electricity than it can handle, which is dangerous. Make sure circuits are designed to handle the device(s) you plug in.

FIX IT: When wiring, it’s about how much power your electronics require versus how much circuits can handle. Plan ahead. Add extra circuits – or high capacity circuits just for high-powered devices.

2. Not Grounded

PROBLEM: Wiring in older homes is not typically grounded, though it should be. This protects from potentially severe electric shock by conducting energy to the ground rather than the outlet.

FIX IT: Update ungrounded wiring by having GFCI (ground fault circuit interrupter) outlets installed. Three-prong outlets contain a live port, a neutral port and a ground port to prevent shock.

3. Short Wires

PROBLEM: Wires should not be stretched to make a connection. The length of a wire is crucial to a proper connection, and poor connections introduce significant risk of injury and fire.

FIX IT: It’s best to allow 3 inches of wire to protrude from the junction box to ensure a safe connection.

4. Overfilled Electrical Box

PROBLEM: The National Electrical Code (NEC) is specific about the number of wires that can safely be housed in a junction box, as live wires produce heat and can be hazardous.

FIX IT: Purchase a larger box before overfilling it – or run the risk of overheating and fire.

5. Unprotected Cables

PROBLEM: If cables are unprotected, especially under ceiling or wall framing, they can be easily damaged. This is a safety concern, and cable protection is included in the NEC residential electrical requirements.

FIX IT: Installing a 1 to 1 ½ inch-thick board alongside the cables protects them.