Top 10 Electrical Mistakes

Wiring problems and mistakes are all too common, and if left uncorrected have the potential to cause short circuits, shocks and even fires. Here’s what to look for and how to fix what you find.

Mistake 1: Making Connections Outside Electrical Boxes

Mistake: No electrical box

Never connect wires outside of electrical boxes. Junction boxes protect the connections from accidental damage and contain sparks and heat from a loose connection or short circuit.

Solution: Add a box

Where connections aren’t contained in an electrical box, install a box and reconnect the wires inside it. The photo shows one way to do this for an exterior light mounted on wood siding. While you’re out there, consider upgrading your outdoor security lights, too.

Mistake 2: Cutting Wires Too Short

Mistake 2: Wires too short

Wires that are cut too short make wire connections difficult and?since you’re more likely to make poor connections?dangerous. Leave the wires long enough to protrude at least 3 in. from the box.

Solution: Extend wires

If you run into short wires, there’s an easy fix. Simply add 6-in. extensions onto the existing wires. The photo shows a type of wire connector that’s easier to install in tight spots. You’ll find these in hardware stores and home centers. Learn how to properly prep wire.

Mistake 3: Leaving Plastic-Sheathed Cable Unprotected

Mistake: Unprotected cable

It’s easy to damage plastic- sheathed cable that’s left exposed between framing members. That’s why the electrical code requires cable to be protected in these areas. Cable is especially vulnerable when it’s run over or under wall or ceiling framing, as shown here.

Solution: Install a 2 x 2

Protect exposed plastic- sheathed cable by nailing or screwing a 1-1/2-in.-thick board alongside the cable. You don’t have to staple the cable to the board. Running wire along a wall? Use metal conduit.

Mistake 4: Poor Support for Outlets and Switches

Mistake: Loose outlet

Loose switches or outlets can look bad, but worse yet, they’re dangerous. Loosely connected outlets can move around, causing the wires to loosen from the terminals. Loose wires can arc and overheat, creating a potential fire hazard.

Solution: Add rigid spacers

Fix loose outlets by shimming under the screws to create a tight connection to the box. You can buy special spacers like we show here at home centers and hardware stores. Other options include small washers or a coil of wire wrapped around the screw. Add some insulation while you’re back there, too.

Mistake 5: Installing a Three-Slot receptacle without a Ground Wire

Solution: Install a two-slot outlet

If you have two-slot outlets, it’s tempting to replace them with three-slot outlets so you can plug in three-prong plugs. But don’t do this unless you’re sure there’s a ground available. Use a tester to see if your outlet is grounded. A series of lights indicates whether the outlet is wired correctly or what fault exists. These testers are readily available at home centers and hardware stores.

If you discover a three-slot outlet in an ungrounded box, the easiest fix is to simply replace it with a two-slot outlet as shown. Dead outlet? Learn how to troubleshoot a dead outlet here.

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