Electrical Safety

The importance of following safe procedures cannot be overstated. What follows are reminders some do’s and don’ts of basic electrical work. They do not substitute for common sense.

Always use caution, care, and good judgment when following the procedures.
Always be sure that the electrical setup is safe; be sure that no circuit is overloaded, and that all power tolls and electrical outlets are properly grounded. Do not use power tools in wet locations.
Never modify a plug by bending or removing prongs. When prongs are bent, loose or missing, replace the entire device.
Don’t use 3-prong to 2-prong cord adapters to overcome ground connections.
Be sure all receptacles and electrical conductors are properly grounded.
If a plug prong breaks off in a receptacle, do not attempt to remove it. Turn off the circuit, and call a licensed electrician.
Be sure receptacles are mounted securely in their boxes and do not move when the plug is inserted. A loose receptacle can cause a short circuit.
Do not use loose receptacles or other faulty electrical equipment until it is repaired or replaced and inspected by a licensed electrician.
Replace all damage electrical enclosures such as receptacle, switch, and junction boxes.
Use extension cords only when necessary, on a short-term basis; never use extension cords in place of permanent wiring.
Be sure all extension cords are properly sized and rated for the use intended.
Keep electrical cords away from areas where they may be stepped on, pinched between door jambs, or otherwise damaged.
Don’t use appliance or extension cords that show signs of wear, such as frayed or dried sheathing or exposed wires.
Visually inspect all electrical equipment and appliances before use.
Never staple, nail, or otherwise attach an extension cord to any surface.
Always turn off tools and appliances before unplugging them.
Never unplug a tool or appliance by yanking on the cord; always remove the cord by the plug.
Always keep the area in front of your main panel clear and dry. Work on a rubber mat or dry board and maintain an unobstructed area of at least 3 feet in front of the panel. The panel must be easily accessed.
Keep dust, lint, and other combustible materials away from electrical panels, receptacles, and appliances.
Keep electrical panel doors closed and latched when not in use.
Keep all electrical equipment away from any source of water unless it is rated for use in wet areas, such as a wet-dry shop vacuum.
Use ground-fault circuit interrupters (GFCIs) wherever possible. GFCIs are required in all wet, damp, or moist areas.
Limit use of receptacles to one appliance. If more than one appliance will be on a circuit, use an approved plug strip with a built-in circuit breaker.
Use proper lighting in areas where the risk of an electrical hazard is present and keep emergency backup lighting readily available.
Keep all energized parts of electrical circuits and equipment enclosed in approved cabinets and enclosures.
Use only tools that have double insulated casings.
Always be aware of the potential hazards when doing electrical work of any kind.

Be sure to use appropriate equipment when doing electrical work (safety glasses, insulated gloves, rubber mats, etc.).

Working Safely with Electricity

Basic Rules of Safety
Safety is, without question, the most important aspect of any electrical work. One split-second mistake can result in serious injury or even death. Many errors are made because of impatience, ignorance, or unnecessary risk-taking. If you consider the potential cost of not following simple, common-sense rules of safety when you are working with electricity, then you will certainly realize the importance of avoiding such mistakes.

The first rule of working with electricity is to shut off the power at your main service-entrance panel before working on a circuit. Always keep a well-maintained flashlight near the panel so that when power is cut off you will not be left standing in dark. Also, be sure to stand on a rubber mat or dry boards, especially if your utility room is damp, and use only one hand to remove or replace a fuse or flip a circuit-breaker switch. After shutting off the power, secure the panel so that no one else will accidentally turn the circuit back on while you are working on it. All circuits should be clearly marked to avoid confusion as to which circuit to shut off. Nevertheless, whenever you do work on a circuit, be doubly sure that it is not hot by testing it, using a circuit tester.

Second, be absolutely positive that you have carefully planned your work that you know every step you’ll take, and that you are not in over your head.

Third, when doing actual wiring and electrical repairs, take precautions to use the correct tools, equipment, and techniques.

While safe electrical work requires the use of specific tools, it depends even more on the use of high-quality tools. Such tools are best purchased form a reputable home center or distributor of electrical supplies and equipment, rather than from a discount store. In the long run, a bargain is seldom a bargain if it endangers your life or property. Besides, well-maintained, high quality tools will add to the versatility and reliability of your tool collection, and they can last a lifetime.

Locating, Measuring, and Marking

Electronic Stud Finder. When you want to locate wood framing inside a wall, you should use an electronic stud finder. Locating concealed framing makes it easier to plan wire runs and to be sure that fasteners applied to the wall will be secured to the framing-not just the drywall. Knowing where framing is located will allow you to avoid drilling and cutting holes in the wrong place or locating electrical boxes where framing will interfere with installation. You can also use a stud finder to determine the location of hidden pipes and existing wiring runs.

Measuring Tape. A heavy-duty 30-foot measuring tape is adequate for most indoor work, whether you are measuring the length of a wire run or the dimensions of a room.

Range Finder. If you want to take a high-tech approach, use an electronic range finder to sonically measure the distance between walls. Then you can use the dimensions to calculate power usage requirements.

Pencils/Felt-Tip Marker. A graphite-lead No. 2 or carpenter’s pencil is useful for marking accurate measurements of any kind, whether on framing members, drywall, or any other surface on which you can write. A medium-weight black or blue felt-tip marker or grease pencil may do for surfaces that are hard to mark with a lead pencil. Markers are especially handy for labeling wires and circuits to prevent hazardous mistakes. It is important that you switch off the appropriate circuit breaker and connect the right wires whenever you are doing electrical work.

Hole-Making, Cutting, and Striking

Wood and Masonry Chisels. A wood Chisel can be used to notch through the outer edge of a top plate or across the face of a stud in a wood-framed wall to make a pathway for fishing wires between a ceiling and a wall or across a wall. A cold chisel is helpful when you must notch, chip, and punch holes in masonry, though a star drill may be more useful for hole making. A star drill is a hardened steel chisel with a star-shaped tip. It is an impact tool that can be easily used with a handheld sledgehammer to punch holes through concrete block or other masonry.

Safety Glasses. When doing electrical work of any kind, you should always wear safety glasses or goggles. A sudden spark or a bit of clipped wire could shoot out and burn or scratch your eye. When drilling overhead it is important to wear safety goggles to keep debris from falling into your eyes as you work. Be sure that the glasses you buy have extendable arms to fit properly around your ears.

Even if you have the proper tools to do your own electrical work, you are only half-prepared for the task. You must also have the right materials and equipment. Every code requirement must be carefully considered before you purchase a single item. Plan your electrical work on paper first so that you will know exactly what to purchase from the service panel and electrical boxes to the receptacles, switches, and fixtures. First, you must determine what you’re installing and how much power it requires. Then you can decide what categories and quantities of wire to buy; how many circuit breakers and at what amperage; whether or not conduit or cable will be used, and what type; and the accessories needed to connect and fasten wires, conduit, cable, and other materials. Carefully identifying everything you need in advance saves you time and money as well as effort.

Representative Loads and Circuits for Residential Electrical Equipment

Appliance	Volt/Amperes	Volts	Gauge/No. of Wires	Circuit Breaker or Fuse in Amps
Range	12, 000	115/230	6/3	60
Built-in oven	4,500	115/230	10/3	30
Range top	6,000	115/230	10/3	30
Dishwasher	1,200	115	12/2	20
Waste-disposal unit	300	115	14 or 12/2	15 or 20
Broiler	1,500	115	12/2	20
Refrigerator	300	115	14 or 12/2	15 or 20
Freezer	350	115	14 or 12/2	15 or 20
Washing machine	1,200	115	12/2	20
Clothes dryer	5,000	115/230	10/3	30
Iron	1,650	115	14 or 12/2	15 or 20
Workbench	1,500	115	12/2	20
Portable Heater	1,300	115	12/2	20
Television	300	115	14 or 12/2	15 or 20
Fixed lighting	1,200	115	14 or 12/2	15 or 20
Room air conditioner	1,200	115	14 or 12/2	15 or 20
Central air conditioner	5,000	115/230	10/3	30
Sump pump	300	115	14 or 12/2	15 or 20
Forced-air furnace	600	115	14 or 12/2	15 or 20
Attic fan	300	115	12/2	20

Maximum Wires in a Box

Box Type and Size	Maximum Number of Wires Permitted
Box Type and Size	18 GA	16 GA	14 GA	12 GA	10 GA	8 GA	6 GA
4”x11/4” Round or Octagonal	8	7	6	5	5	4	2
4”x 1 ½” Round or Octagonal	10	8	7	6	6	5	3
4”x 2 1/8” Round or Octagonal	14	12	10	9	8	7	4
4”x 1 ¼” Square	12	10	9	8	7	6	3
4”x 1 ½” Square	14	12	10	9	8	7	4
4”x 2 1/8” Square	20	17	15	13	12	10	6
3”x 2” x2” Device Box	6	5	5	4	4	3	2
3”x 2” x2 1/2” Device Box	8	7	6	5	5	4	2
3” x2” x2 ¾” Device Box	9	8	7	6	5	4	2
3” x2” x3 1/2” Device Box	12	10	9	8	7	6	3
4” x2 1/8”x1 ½” Device Box	6	5	5	4	4	3	2
4” x2 1/8 x1 7/8” Device Box	8	7	6	5	5	4	2
4” x2 1/8” x2 1/8” Device Box	9	8	7	6	5	4	2
3 ¾” x2” x2 1/2” Device Box	9	8	7	6	5	4	2
3 3/4” x2 x3 1/2” Device Box	14	12	10	9	8	7	4

Creating New Circuits
Remodeling plans often call for adding new electrical circuits to meet increased demands. In addition, appliances such as dishwashers and waste-disposal units often require a separate circuit to power the appliance. You will need to run wiring from the appliance to the main panel.

Preparing for Inspection. Once new framing walls are ready to be wired and electrical boxes have all been put in place, carefully begin pulling the cable through the framing. When you insert a cable end into an electrical box, leave a minimum of 6 inches of extra cable, cutting away the excess. Using a cable staple, secure the cable at a maximum of 8 inches above the single-device box. After you have run all cables through the framing and into the electrical boxes, rip back and remove the sheathing from the cable ends in each box; then strip the individual wires. Before a rough-in inspection can be done, you must also splice together the grounding wires using either green wire connectors or wire crimping ferrules. Then place the wires securely in their boxes.

After a rough-in inspection is performed, install the receptacles and switches. Wait until the drywall is in place before doing this work. When the walls are completed and all of the boxes wired, you can install cover plates and turn on the power. Check each receptacle, using a plug-in receptacle analyzer, to verify that all of the wiring has been properly done. Install the light fixtures; then confirm that they are all working. Once you have completed all of this, your work will be ready for final inspection. The inspector will reexamine your work, performing many of the same circuit tests as you.

Opening and Closing Walls
Running cables through existing walls and joist spaces is a lot more complicated than running cables in new construction. Because you cannot see into finished framing cavities, fishing cables through walls and ceilings requires great patience and more than a little skill.

If you have access to walls from a basement or attic, you can get power into walls by fishing the cable vertically instead of horizontally through the structural framing. In many cases, running cable the long way around to complete a circuit may be the easiest route, even if you have to spend more money for cable. The cost of the cable is likely to be much less than that of ripping into walls and ceilings. If you must run cable across existing framing, for example, you may have to cut into drywall in order to position the cable properly. It is a good idea to take time initially to explore alternative routes the cable might follow. Try to determine the best route; then make a rough sketch or map of the cable route. This will undoubtedly save you time and money later.

Before running cable, first decide where to locate your new switch, outlet, or junction box; then determine which walls or ceilings, if any, need to be opened to efficiently route the cable to this point. You can cut openings in drywall using a utility knife, mini-hacksaw, or keyhole or saber saw. After you make your cut, either remove the scrap or knock it back between the framing members.

In an unfinished basement, you may encounter hollow concrete-block walls or poured steel-reinforced solid concrete walls. Although it is possible to cut into a hollow concrete block wall, it isn’t practical,. For block and concrete walls, it is best to install metal surface raceways or electrical conduit, and surface-mount your electrical boxes and wiring. Use a masonry bit on your power drill to make pilot holes for masonry anchors; then anchor the boxes and conduit clamps directly to the wall. Am alternative is to pack out the wall using 2x4 furring lumber, either on flat or on edge, spaced at 16 inches on centre. If you install the furring flat, you will have to use special electrical boxes that are made to fit within a 1 ½ inch wall cavity. Avoid using handy boxes because these do not have enough room to contain properly spliced wires.

Fishing Cable
One way to get cable into an existing stud wall is by running it down from an already functioning electrical box, into a basement or crawl space, and over to the location in the wall of the new electrical box. From here you can fish the wire up into the appropriate wall cavity.

WHAT “NEUTRAL” MEANS
The neutral conductor is the conductor that leads back to the center tap of the utility transformer. It is connected to earth at two locations: the utility transformer and the main panel. That is why it is sometimes referred to as the grounded neutral conductor. Its designation is white or a white tape on a black cable.
Neutral current is commonly referred to a return current, because once the current passes through the load, the white insulated neutral conductor makes the complete circuit back to the utility transformer. All electrical current must make a complete loop. The current starts at the utility transformer and must therefore return to the transformer; the neutral is simply the return part of that loop.

The neutral cable or wire can kill you just as readily as a “hot” cable. The same current that flows in a hot conductor flows out the neutral. If you place yourself in series within that loop, even on the neutral side, you will be electrocuted.

Safety first
          Electricians and others who have worked with electricity for years know they always have to follow safety precautions. They’ve heard hair-raising stories about what happens to people who ignore safe work habits. This website is loaded with safety reminders to help you stay safe while you work. Follow them.
          Electricity deserves your respect. Consider how household current can affect the human body. If your feet are dry and you are wearing rubber-soled shoes, receiving a shock from a 120 volt circuit will definitely hurt, but it will probably not cause you serious harm. However, if conditions are wet or your feet are not protected with rubber soled shoes and you are standing on the ground or on a metal ladder, 120 volts can cause the muscles in your hands to contract so that you grasp the source of current involuntarily. The current will cause your heart to beat wildly, very likely to the point of heart failure. Expect the same consequence if you touch both live wires of a 240 volt current, even if your feet are dry and protected. Children are in even greater danger.
          The wiring in a modern home should have safety features, such as grounding and ground fault circuit interruption. Both greatly reduce the possibility of dangerous shock, but they don’t offer complete protection to a person working on exposed wires and devices. This is why professional electricians work carefully. So should you.
          Here are a few basic rules for safe electrical work. Follow them at all times, even when you are doing “just a little” electrical job.

BE PROTECTED FROM THE GROUND UP
Always keep your feet protected with rubber soles, to lessen the effects of a possible shock. In damp areas stand on dry boards. POST A SIGN ON THE PANEL
Take steps to make absolutely certain that no one will turn the power back on while you are working. If possible, lock the service panel.

USE RUBBER-GRIPPED TOOLS
Don’t use tools with plastic or wood handles unless they also have rubber sleeves to provide extra protection against electrical shock

USE ELECTRICIAN’S TAPE
Electrician’s tape provides extra protection against dangerous ground faults and shorts. Even if not required by code, wrap wire nuts and terminals with tape.

Shut off the power
If there is no electrical current, you cannot receive a shock. Always shut off power to the circuit you are working on. Do this by flipping a circuit breaker or completely unscrewing a fuse. Then test for the presence of power.

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 you will be working on. Test everything twice.
Regularly test your tester to make sure it will indeed tell you when power is present. Touch it to a live circuit and see that it glows just before every test. Many a war story tells 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 people not to restore power.

Stay Focused
Most electrical mishaps occur because of small mental mistakes. Remove all distractions. Keep people, especially children, well out of the way. Turn the radio off. 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
Rubber grips offer more protection than plastic or wood handles, so always use rubber-gripped tools when wiring. Get in the habit of using them correctly: Grab by the handle, not the metal shaft. Make sure your pliers and cutting tools have rubber grips that are long enough so you will not be tempted to touch the metal while working. Replace a tool when the rubber is damaged.
Wear rubber-soled shoes, such as athletic shoes, and perhaps rubber gloves, so that electrical current will not travel easily through you and into the ground. Never work with wet feet or while standing on a wet surface. Do not wear jewelry of a watch-anything that could possibly get snagged on wires. Use a fiberglass or wood ladder; an aluminum ladder conducts electricity.

Ask questions
Electricians consult with each other all the time, even when they are 99 percent sure they already understand. Never proceed with an installation or repair unless you are completely sure you know what you are doing.

ACCESS FOR CABLE
The next step is to study possible access routes for running cable from the power source to the locations for new devices. But to do that, you’ll first need to bone up on some basic house anatomy.
Wood-frame homes are not all built the same way, but most have 2x4 stud walls, 2x8 (or larger) floor joists, and 2x6 (or larger) ceiling joists. These wooden structural members are normally spaced 16 inches apart from center to center. In some new homes, however, the spacing is 24 inches, and in some roughly build older homes, it’s somewhat random. In new construction, all rough wiring is done before wall, ceiling, and floor coverings are added. Extending a circuit in a finished house is a different story; you have to find ways to route cable behind existing walls, above ceilings, and under floors.
The best route is one that is direct and accessible, but accessibility is generally more important than directness. The savings in time and effort from avoiding extensive cutting and patching of walls, ceilings, and floors nearly always offsets the added material costs for an indirect cable run.

WHERE YOU HAVE ACCESS:
In some parts of your home, installing cable and boxes might be quite easy. These are areas such as attic floors and unfinished basement ceilings where wall, ceiling, or floor coverings are attached to only one side of the framing. You simply work from the uncovered side, drilling holes and threading cable through studs or joists. You can also “fish” cable through finished walls from these locations.
When working in an attic, don’t put any weight on the floor area between the joists. Step only on the joists or on planks laid across them, and be sure to walk gently so you don’t crack the ceiling surface of the room below.

WHERE ACCESS IS LIMITED:
Getting cables into walls, floors, or ceilings that have coverings on both sides involves cutting through the coverings, installing cable, and patching up the holes. The amount and difficulty of cutting and patching depend only partly on where the cable goes; surface material is also a factor.

Gypsum wallboard, the most common wall and ceiling covering, is relatively easy to cut away and replace. But some other materials-such as ceramic tile, certain types of wood flooring, and plaster-are more difficult to cut and patch and should be left alone when possible.

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