Electricity

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Volts, Amps and Watts

Electricity flows through wires much like water flows through pipes. The electrical pressure that causes current to flow is measured in volts. This pressure is set by your electrical utility company and is 120 volts for most circuits. The rate at which the electricity flows is measured in amps (amperes). The amount of power a lamp or appliance actually draws is measured in watts, a measure that takes both volts and amps into account. For example, a light bulb that draws 1/2 amp through a 120 volt circuit uses 60 watts (1/2 x 120).

Grounding For Safety

Grounding provides a safety net for your house’s electrical system. Ground wires normally don’t carry current but in an emergency they provide a safe path of least resistance to the ground for an abnormal current flow. This helps to protect both you and your electrical gear. The electrical code now requires that all new and upgraded wiring be fully grounded. But in older homes the receptacles and lighting fixtures are often not grounded. Ungrounded receptacles have only two slots while grounded ones have a third round hole. This allows them to accept the three-prong plugs found on many heavy-duty appliances that need to be grounded to be used safely. However your receptacles may have that third round hole without really being grounded. People often replace ungrounded receptacles with grounded ones and leave the grounding unconnected. This is dangerous because it encourages you to use the receptacles for equipment that should be grounded. To tell if a receptacle is grounded, use an inexpensive receptacle analyzer. But of course it is safer to use older ungrounded receptacles for fixtures like lights that don’t demand a lot of power. But if you suspect that your entire electrical system is not properly grounded then have it inspected by an electrician.