ELECTRICAL CODES MUST BE FOLLOWED! Electrical codes are enforced to make sure electrical installations are safe and work properly, and inspectors don’t kid around.
• When applying at your local building office for permits to do electrical work, present precise, easy-to-read drawings and include a complete list of materials for the project.
• Installations need to be seen to be inspected.
Don't put up drywall or cover new wiring until the inspectors have signed off. If they don’t approve the job, you'll do it over, and that can be expensive.
IMPORTANT NOTE: The projects in this section follow common national guidelines. Local codes can be stricter than national standards. Check local requirements carefully before you begin.
How the electrical system works
Electricity (current) is the flow of electrons through a conductor (usually copper or aluminum wire). The current travels in a loop, called a circuit, through a “hot” wire (usually black or red) to a fixture and returns through a “neutral” wire (usually white), completing the circuit. When the circuit is broken, the current ceases. The system is grounded to the earth to prevent a user from being shocked from damaged or defective wiring.
VOLTAGE AND AMPS. Voltage is electrical pressure exerted by the power source. Most household fixtures use 120 or 240 volts. Wires, appliances, and fixtures have different resistances to the voltage—the thicker the wire, the less resistance. Amperes and watts refer to the amount of electrical current used by devices in the system (such as a light bulb).
POWERING YOUR HOME. Electricity flows from the utility provider through high-voltage wires to transformers that reduce the amount of power to 120 volts per wire. The wires enter your home through a service head, which attaches to a meter that records your power use. The wires then enter the service panel, which divides the power into circuits and then distributes power to outlets throughout your home.
Service to most homes is three-wire— two “hot” wires carrying power inside and one “neutral” wire completing the circuit. Two hot wires means that a home can run 120-volt and 240-volt circuits. Older homes with only one hot and a neutral are limited to 120-volt service.
KNOW YOUR LIMITS. Most repairs and installations can be performed safely inside the home. For any outdoor repairs or installations, including the service head and wires that feed the main shutoff in the service panel, call your local utility for service; that is its responsibility.
RESPECT YOUR BREAKER BOX
• Always know what’s hot. The wires entering from the outside are always hot.
• Don't touch the bus bar; it remains hot even when a breaker has been shut off.
• Keep the cover on and closed (preferably locked) at all times.
• Post a circuit map on the door.
• Keep the area around the box clear and have a charged flashlight handy.
• Always wear rubber-soled shoes.
• Never clip temporary lines into the panel. (Welders and sanders will often want to clip temporary extension lines to the hot and neutral bars. Don't let them.)
TECHNICAL ELECTRICAL - An electrical outlet is any place where electricity leaves the wires to perform a service—such as at a light fixture. A receptacle is an outlet where electricity exits the system through a plug. A device is something that carries, but does not use, electricity, such as a receptacle or switch. A fixture is an electrical outlet that is permanently fixed in place, and an appliance is a movable user of electricity. An overhead light is a fixture while a toaster is an appliance.
Electricity deserves your attention and respect. The wiring in a modern home should have safety features, such as grounding and ground fault circuit interruption. While both greatly reduce the possibility of dangerous shock, they fail to offer complete protection to a person working on exposed wires and devices. This danger is why professional electricians work very carefully; so should you.
SHUT OFF THE POWER. If there is no electrical current, you cannot receive a shock. O Always shut off power to the circuit on which you are working. Do this by flipping a circuit breaker or completely unscrewing a fuse. Then make sure you chose the right circuit by using a voltage meter to test the line: It should read zero.
TEST FOR POWER. Be aware that more than one circuit may be running in a box. Test all the wires in an open box for power, not just the wires on which you will be working. Test everything twice.
STAY FOCUSED. Most electrical mishaps occur because of small, mental mistakes. Stories abound of someone turning off the power, only to have a family member or coworker turn it back on while work is in progress. Post a sign telling others not to restore power; lock the service panel if possible. Remove all distractions. Keep others, especially children, well out of the way. Even after turning off the power, work as if the wires are live. Work methodically and double-check all connections before restoring power.
USE PROTECTIVE TOOLS AND CLOTHING. Always use rubber-gripped tools. Grab tools by the handle, not the metal shaft. Don’t touch any metal while working. Wear rubber-soled shoes and perhaps rubber gloves. Never work with wet feet or while standing on a wet surface. Do not wear jewelry or a watch—anything that could possibly get snagged on wires. Use a fiberglass or wooden ladder; an aluminum ladder conducts electricity.
ASK QUESTIONS. Never proceed with an installation or repair unless you are completely sure of what you are doing. Don’t hesitate to ask “stupid” questions of electrical experts; they know there aren’t any.
SHOCKING STORY - A neighbor told me a potentially shocking story. He was doing some electrical upgrades while his family was out of town. He turned off the power at the breaker box just like you're supposed to but didn't put up a warning note. Lucky he was at the store and not connecting circuits when the family showed up early, found the lights out, and hit the breaker. Always put a warning on the box.