Electric Wiring Safety

Wire Color Code

Electrical wiring is all about safety. Install an outlet properly and it's as safe as it can be; install it improperly and it's potentially deadly. That's why there are so many rules surrounding electrical wiring and installations. The rules can be complicated, for sure, and sometimes confusing even for master electricians, but there are basic concepts and practices that apply to almost every electrical wiring project. Electrical hazards are the third-leading cause of fatal injuries among construction workers. One of every eight-construction industry deaths involves electricity.

Here's a look at five of the most important rules that will help keep you safe:

Electric Wiring Safety1) Test for Power - The best way to prevent electrical shock is to test wires and devices for power before working on them or near them. Simply shutting off the power isn't good enough.

Electric Wiring Safety2) Check Amperage Ratings - All electrical wiring and devices have an amperage, or amp, rating. This is the maximum amount of electrical current they can safely carry. Most standard household circuits are rated for 15 amps or 20 amps, while large-appliance circuits (such as for electric dryers and ranges) may be rated for 30, 40, 50, or more amps. 

Electric Wiring Safety3) Make Tight Connections - Electricity travels along conductors, such as wires and the metal contacts of outlets and sockets. Tight connections between conductors create smooth transitions from one conductor to another. But loose connections act like speed bumps, restricting the flow and creating friction and heat. Very loose connections can lead to arching, in which electricity jumps through the air from one conductor to another, creating tremendous heat.  Prevent fire hazards by making sure all connections are tight and have full contact of the conductors being joined. When splicing wires together, always use wire connectors ("wire nuts").  

Electric Wiring Safety4) Respect Grounding and Polarization - Grounding and polarization are essential for the safety of modern electrical systems. Grounding provides a safe path for stray electrical current caused by a fault or other problem in a circuit. Polarization ensures that electrical current travels from the source along "hot" wires and returns to the source along neutral wires. Always follow manufacturer's wiring diagrams and understand—and use—your home's grounding system to ensure grounding and polarization remain intact.  

Electric Wiring Safety5) Box It, Clamp It - The National Electrical Code (NEC) requires that all wiring connections be made in an appropriate enclosure. In most cases, this means an electrical box. Enclosures not only protect the connections—and protect people from accidental contact with those connections—they also provide means for securing conductors (like electrical cables) and devices. The rule here is simple: don't be lazy. If you need to make a wiring splice, install a junction box and secure the cables to the box with cable clamps. Never leave a splice or other connection exposed or unsecured. 

Ryan’s Story

Ryan and his supervisor were finishing the electrical wiring of an outdoor floodlight. Ryan began removing the insulation from a normal house wiring unit, using an insulated wire stripper. His right thumb and right index finger contacted the non-insulated part of the wire stripper. The 110-volt circuit had not been shut off at the panel box. Ryan received an electrical shock and fell to the ground. The ambulance soon arrived, but he was pronounced dead upon arrival at the hospital.

  • How would you prevent an incident like this?
  • Have you or anyone you know ever had an electrical injury? If so, what happened?

Remember This

  • De-energize electrical circuits before doing any type of work on them.
  • Use lockout devices to prevent a circuit from becoming live.
  • Put a tag on the locked device, indicating that it should not be turned on.
  • Clearly identify the disconnected power source and circuits.
  • Use an AC voltage tester to verify that the electrical power is off.
  • Use insulated tools and gloves when working on electrical wires.