What's The Green Wire For?

One of the most common problems we find with electrical installations, whether it be a do it yourself renovation, or even new construction, is finding that the ground connection is not properly terminated to light fixtures, switches and outlets.  They will work without making that connection, but for devices that include a ground connection, it is very dangerous to leave it disconnected.

What does the ground connection look like?  It’s the green screw on light switches and receptacles, and it is usually a green or bare wire on light fixtures and ceiling fans.

Why is it important?  The ground wire is used to make sure that the metal surfaces a person could come in contact with in an electrical system do not become energized, creating a shock hazard.  When properly connected, the ground wire creates a “short circuit” pathway for electrical current to flow in a large enough volume to trip the circuit breaker off in the event that the “hot” wire comes in contact with any metal it is not suppose to.  Without this ground pathway, current can’t flow, and the breaker can’t trip.   The metal would then become energized, waiting for someone to touch it.  When a person touches the energized metal they become the pathway for current to flow, leading to injury and sometimes death.

It’s easy to think that this is a minor issue, especially when you look at a plastic wall receptacle with a plastic plate.  You may think to yourself, it’s plastic so what could be the harm in leaving the ground wire disconnected?  The answer is that the plastic plate is held in place with a metal screw that connects to the metal yoke (or frame) of the receptacle.  If things go wrong and the receptacle is not grounded, the screw could become energized.  There have been reported incidents of toddlers leaning against the wall with their backs pressed against receptacles getting shocked and badly injured in this exact scenario.

Another function of the ground wire is to protect equipment from damage.  One specific example of this is surge protection power strips.  They will not function at all unless they are plugged into a grounded receptacle.

In houses built prior to the early 1960’s, electrical circuits were not required to include a ground wire.  In these houses it is not possible to ground electrical devices unless the electrical system is upgraded, including properly installing a ground wire to electrical outlets, light fixtures, etc.  This does not mean that you must re-wire the entire house to keep you and your family safe.  There are some specific steps that the National Electric Code has in place to allow older homes to become safer homes without being so invasive as to rip out all of the existing wiring.  Installing a proper grounding system, adding GFCI protection, and installing ground wires to existing receptacles are a few of these solutions.

Wondering if your electrical system is properly grounded?  Give Us A Call.

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