1. Making a connection outside an electrical box
Wires should never be connected outside of an electrical box. A junction box is designed to protect connected wires from getting damaged by accident and keep any heat or sparks caused by a lose connection contained.
2. Cutting wires too short
If you cut wires too short it makes it more difficult to connect them which can be dangerous. Wires should be cut long enough to stick out three inches or more from a junction box.
3. Leaving an unprotected cable
It’s illegal to leave plastic sheathed cables unprotected as they can be easily damaged. Cable should be well protected, particularly when run through ceilings or under floors.
4. Inadequate switch and outlet support
Outlets and switches that are loose are not only an eyesore but can also be extremely dangerous. A poorly connected outlet is able to move easily which can lead to loosened wires. These can overheat and potentially cause a fire.
5. Placing a junction box behind a wall surface
If your wall surface is made from a combustible material such as wood then junction boxes must be placed flush and not recessed.
6. Failing to use a cable clamp
When you don’t secure cable correctly connections can be strained leading to loosening of the wires. Metal junction boxes can cut into insulation around wires left unsecured. Most plastic cable boxes have built in cable clamps and in metal boxes cables must be connected using an approved clamp.
7. Overfilling a junction box
You should always ensure that the junction box you plan to use is large enough for the job in hand before you install it. An overfilled junction box can easily overheat and cause a fire hazard.
8. Reversing neutral and live wires
Connecting the live wire to an outlet’s neutral terminal can result in a potentially fatal shock. Unfortunately a serious mistake like this is often not realised until someone is hurt because appliances and lights will still work even if the circuit is incorrectly configured.
Make sure you’ve connected the correct wire to the neutral terminal on light fixtures and power outlets to avoid a nasty shock later on.