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Safety Getting the right answers to wiring questions
A few years back, I saw a comical piece of paper in a university office that listed consulting fees. As I recall the list went something like this:
At the time, I was amused, but I have since realized how true the line about "Wrong Answers" can be. Many times when you are doing home repair or remodeling, incorrect answers to "how-to" questions could end up costing you more than no answer at all. Over the last couple of years, I have received bad advice when asking about installing safety features designed to protect equipment and people. I have encountered wrong answers most often when I ask about electrical wiring. Most of the confusion is encountered when discussing the proper installation of neutral (or grounded) circuits and grounding circuits. Neutral circuits are used to "complete" the flow course for electrons (current) carried to the light, motor or other device by the "hot" wire. Current returns on the neutral wire to the service panel. Under perfect conditions, this current carrying circuit can also have varying small levels of voltage depending on the loads supplied by the circuit. These tiny voltages are necessary for the electrons to flow since the perfect conductor has not been invented, yet. The neutral circuit differs from the grounding circuit, which also has its own distinct purpose. Grounding circuits are a safety precaution for electrical wiring. They offer a "safe" path back to the circuit for leaking current which has escaped from the hot and neutral circuits through faulty insulation or accidental contact between current-carrying wires and metal surfaces. The leaking current seeks this path back to the electrical circuit because of its resistance is lower than your body's resistance. In the event of a fault, grounding circuits also allow circuit breakers and fuses to function quickly because of the very high flow of current in the circuit. These two circuits must be separate (different wires) until they are connected to the grounding bar at the service entrance panel. I have been told by electricians and by people working in electrical supply departments of home supply stores that the two circuits can be completed on the same wire. This is NOT a correct wiring practice! As I mentioned, there may be voltage on the neutral wire from the load. If the metal case of the appliance is connected, it may be "hot." This is especially dangerous if there are any problems with the neutral conductor or connections between the load and the service entrance. A person coming in contact with metal cases that complete a circuit would be electrocuted. Proper installation procedures will help prevent this from happening. These procedures are outlined in the National Electrical Code, as well as in wiring handbooks from MidWest Plan Service through the University of Illinois Cooperative Extension Service. Contact your power supplier or a reputable licensed electrician for advice when attempting home wiring repairs or electric equipment installations. Remember, the advice you receive is only as good as the credentials of the person you ask.
Bill Campbell is an Extension Educator, Farm Systems, at the Springfield Extension Center, Cooperative Extension Service, University of Illinois. You can write to Campbell in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: 217-782-6515. E-Mail: campbellw@idea. ag.uiuc. edu
12 ILLINOIS COUNTRY LIVING FEBRUARY 1996 |
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