The Importance of Grounding Your Appliances?

Be sure all of your appliances are grounded. Electrical current always takes the path of least resistance. If an appliance is grounded to a cold water line or through a polarized, three-wire plug to an electrical system that is properly grounded, any current leakage will flow through the grounding conductor rather than through your body. Combine this with a safety-designed appliance in which all electrical -terminals and conductors are shielded and you have practically eliminated the possibility of an electrical shock while using the appliance. Most power tools are grounded through a polarized cord. The use of double insulation does not require grounding since it allows the tool to "fail safe" in the event of an insulation breakdown.
How much appliance current flow is dangerous? It depends to some extent upon the individual person and also his general health conditions. A small amount of current indeed, con­sidering that the average appliances household circuit is capable of conducting at least 15 amperes. Somewhere between 5/1000ths and 25/1000ths of an ampere a strong shock occurs, and often the victim is unable to control his muscles to release himself. This is a twitching of the heart muscle that prevents its normal rhythmic pumping action. At 100 mill amperes or more the electrical current can interrupt the breathing process. That's a very small amount of current flow. That's only 11150 of the amount of current that the circuit in your home is capable of carrying less than it takes light a flashlight bulb.
For a number of years the appliance national electric code has required a third wire to be used for equipment grounding in most home electrical circuits. Properly installed appliance gives protection by grounding the metal enclosure of any appliance with polarized plugs. If you have any doubt about the grounding system in your home, have an elec­trician check by using a "meager," an instrument designed to test the condition of a grounding electrode. You'll notice when you insert a polarized plug that the grounding prong is slightly longer than the ethers. Entering the receptacle first, the longer prong grounds the equipment before electrical power is applied to the rest of the plug.
Many new appliances come with an adapter for the polarized plug in case a polarized receptacle isn't available. These are acceptable if the adapter is attached to the center screw of the receptacle cover and if the receptacle boxes itself is properly grounded. Chances are it may not be. Therefore it’s recommend strongly that an external ground wire be run from the receptacle cover plate screw to a cold water line. The best bet of all is to have a competent appliance repair technician install a grounded receptacle. If your home doesn't have them, chances are that it's time for a check of the wiring anyway.

Tom Salgado
December 2010