How to Protect Residential Electrical Wires

The protection of residential electrical wiring falls under the regulation of the National Electrical Code (NEC).

There are two basic areas for protecting these current-carrying wires: mechanical and electrical overload. Mechanical damage occurs whenever the wires or cables are installed in such a way that objects or people can come into contact and cause breaks in the wires. Electrical overloads are always an ever-present hazard for any electrical device. All wires must have some form of overload protection in the form of circuit breakers or fuses. .

Place all electrical wiring and cable assemblies inside of an approved metal or plastic electrical conduit. Generally all wires, installed in or around homes, that are exposed to the open air need to be placed inside an appropriately sized conduit. Wires that pass through concrete slabs or wall openings must also be contained inside an approved enclosure. Cable assemblies that hang in free air must be installed above a certain height so people and vehicles cannot come into contact with the hanging wires.

Install properly rated circuit breakers or fuses for separate electrical circuits. In most typical applications, wire size and circuit breaker protection must go together. A 12-gauge wire, for example, can safely carry 20 amperes of power. It is illegal for a 12-gauge wire to be connected into a 30-ampere circuit breaker or fuse. Other wire sizes fall into the same category for circuit protection. A 14-gauge wire is capable of conducting 15 amperes, while a 10-gauge wire can handle 30 amperes. Consult the NEC Table(s) 310 for other maximum amperage of wire capacity.

Use GFCI circuit protection on all outdoor and wet environment electrical power. This includes countertop receptacles installed in areas near and around kitchen sinks. Power outlets in the bathroom, regardless of their location, must also be protected by this fast-acting power cut-off device. All outlets installed outdoors--and, in most cases, garages--must be controlled by the GFCI breaker.

Consult the local electrical inspector or have your home checked by a licensed electrician. Older homes may be suspect as to having an up-to-date electrical system. This includes a full earth ground running throughout the home's electrical system. The earth ground is an important safety feature for all electrical wiring. This "third" wire is a bare copper conductor that aids the circuit breaker in performing its overloading protection function. In some cases a GFCI breaker can be installed in place of rewiring the entire home for a "third" wire earth ground system.

Things You Will Need

  • Metal or plastic electrical conduit
  • Circuit breakers
  • Ground Fault Circuit Interrupters (GFCIs)


  • Consult local electrical rules and regulations. In many cases these local governing bodies may have rules that exceed those required by the NEC.
  • Consult the NEC for the correct size of conduit pipes as each installation will be different due to locality, and certain exceptions may apply.