Electrical

Common copper wire sizes for an electric water heater are A) #16, #18. B) #10, #8. C) #16, #8. D) #12, #10.

The answer is #12, #10. Common wire sizes for water heaters are #12 and #10 gauge.

Assuming copper, standard wire type, and normal temperature rating, what is the typical conductor size (in awg) for a 60A service in the U.S.? A) #6 B) #3 C) #4 D) #10

The answer is #6. #6 gauge wire is adequate for 60 amp service.

In general, modern 120V circuits can accommodate how many outlets and/or light fixtures? A) 8 B) 16 C) 12 D) 10

The answer is 12. Roughly 12 outlets and/or light fixtures are permitted per circuit.

A service box with a black wire, a red wire, a white wire, and two 200A fuses indicates a A) 120/240V, 400A service. B) 120/240V, 200A service. C) 120V, 200A service. D) 120V, 400A service.

The answer is 120/240V, 200A SERVICE. A black, red, and white wire and 200 amp fuses indicate a 120/240 volt, 200 amp service.

The standard house voltage is A) 120V. B) 120/208V. C) 120/240V. D) 100A.

The answer is 120/240V. The standard house voltage is 120/240 volts.

Which of the following is not a common service amperage? A) 100A B) 175A C) 60A D) 400A

The answer is 175A. A 175 amp service is not common.

The power available in a typical 15A, 120V household circuit is A) 3600W. B) 1500W. C) 1800W. D) 1000W.

The answer is 1800W. P = VI, P = 120 × 15 = 1,800 watts.

Plastic sheathing on branch wiring became popular in the A) 1980s. B) 1950s. C) 1960s. D) 1970s.

The answer is 1970s. Plastic sheathing on branch wiring became popular in the 1970's.

Assuming copper, standard wire type, and normal temperature rating, what is the typical conductor size (in awg) for a 200A service in the U.S.? A) 3/0 B) 1/0 C) 2/0 D) #2

The answer is 2/0. A 200 amp service must have 2/0 gauge wire in the U.S.

You observe #6 gauge copper wires entering a service box with two 60A fuses inside. From the service box, #3 copper conductors lead to a newer combination panel that has a 100A main breaker. You should report the service size as A) 100A. B) 160A. C) 60A. D) 120A.

The answer is 60A. This is a 60-amp service, limited by the service entrance conductors and the main fuses. It doesn't matter what is downstream of that.

Aluminum wiring is still used on A) 10 gauge circuits. B) 12 gauge circuits. C) commercial applications only. D) 8 gauge circuits.

The answer is 8 GAUGE CIRCUITS. Aluminum wiring is still used on #8 gauge circuits. Stranded aluminum wire is still common. That includes wires that are #8 gauge and larger.

What is a type P fuse? A) A gfci fuse B) A heat sensitive fuse C) A "power" fuse, for 30A or more loads D) A time-delay fuse

The answer is A HEAT SENSITIVE FUSE. A type P fuse is a heat sensitive fuse.

A multi-wire circuit has A) protection from circuit breakers, not fuses. B) a red and a black wire. C) two neutral wires. D) two ground wires.

The answer is A RED AND A BLACK WIRE. A multi-wire circuit has a red and black wire.

Four service entrance conductors indicates A) a 400A service. B) a 120V service. C) a 240V service. D) a three-phase service.

The answer is A THREE-PHASE SERVICE. Four service entrance conductors indicate a three-phase service, which is beyond our scope.

Twist-on connectors (wire nuts) A) are also called solderless connectors. B) should be used only on soldered connections. C) are not permitted on knob-and-tube wiring. D) replace junction boxes.

The answer is ARE ALSO CALLED SOLDERLESS CONNECTORS. Wire nuts are also called solderless connectors.

Panels used with aluminum wire should A) contain at least 20 branch circuits. B) be rated CUAL. C) be circuit breaker rather than fuse-type. D) be rated CO/ALR.

The answer is BE RATED CUAL. Panels used with aluminum wires should be rated CUAL.

A 60A service A) can be adequate in some cases. B) is not allowed in new construction in North America. C) is not suitable for a 240V service. D) requires a minimum #3 awg copper wire.

The answer is CAN BE ADEQUATE IN SOME CASES. A 60 amp service can be adequate in some cases.

You notice a wooden post as the support for the service drop. You should A) tug on the service drop wires to make sure the mast doesn't give. B) check for rot, damage, or movement. C) recommend replacing it right away with a steel mast. D) assume that you'll find obsolete equipment inside the house.

The answer is CHECK FOR ROT, DAMAGE, OR MOVEMENT. When you see a wooden post supporting the service drop, you should check for rot, damage, or movement.

The service drop wires A) must always be in conduit. B) are a reliable indicator of service size. C) connect to the house at the drip loop. D) are usually the homeowner's responsibility.

The answer is CONNECT TO THE HOUSE AT THE DRIP LOOP. Service drop wires join the house at the drip loop.

After entering the service box, the neutral service entrance conductor should A) go directly to the distribution panel. B) connect to the terminal with the grounding electrode conductor and the service neutral. C) connect to the main breaker. D) connect to the main fuses on the line side.

The answer is CONNECT TO THE TERMINAL WITH THE GROUNDING ELECTRODE CONDUCTOR AND THE SERVICE NEUTRAL. The neutral service entrance conductor should connect to the terminal with the grounding conductor and the service neutral.

Service entrance (se) cable must be securely clamped to the house A) every 6 feet. B) every 30 inches, generally. C) using brass clamps and screws. D) every 12 inches, using rustproof fasteners.

The answer is EVERY 30 INCHES, GENERALLY. Service entrance cables should be clamped to the house every 30 inches typically.

Which of the following is not an approved grounding method? A) Metallic underground water piping B) Metal frame of a building C) Gas piping D) Ground rods

The answer is GAS PIPING. Gas piping is not an approved grounding method.

White wires can sometimes act as black wires A) in multi-wire branch circuits. B) on a dedicated circuit for a clothes dryer. C) by design on a reverse polarity circuit. D) in 240 volt circuits.

The answer is IN 240 VOLT CIRCUITS. White wires can sometimes act as black wires in 240 volt circuits.

Overfusing is A) installing a fuse or breaker that is rated too big for the conductor. B) installing too many fuse receptors into a panel, causing a potential overload. C) the clipping of breaker handles so that they operate together. D) installing fuses in a holder requires that two be removed at once.

The answer is INSTALLING A FUSE OR BREAKER THAT IS RATED TOO BIG FOR THE CONDUCTOR. Overfusing refers to installing a fuse or breaker that is too big for the conductor.

The grounded service conductor A) cannot be aluminum. B) connects to the water pipe and/or the ground rod. C) is called the neutral. D) must be bonded to the gas piping.

The answer is IS CALLED THE NEUTRAL. The grounded service conductor is the neutral.

Special grease on aluminum wires A) is found on number 12 and 10 gauge wires. B) is found on service entrance wires only. C) is used to control creep. D) is found on stranded wires.

The answer is IS FOUND ON STRANDED WIRES. The special grease on aluminum wires is typically used on stranded wires.

Overloading the neutral wire on a multi-wire branch circuit A) means that the neutral wire was undersized. B) indicates a short in the circuit. C) is the result of failing to fuse the neutral. D) is likely if the black and red wires are powered from the same bus.

The answer is IS LIKELY IF THE BLACK AND RED WIRES ARE POWERED FROM THE SAME BUS. Overloading the neutral wire on a multi-wire branch circuit is likely if the black and red wires are powered from the same bus.

Knob-and-tube wire buried in insulation A) insures the wires won't come in contact with each other. B) is not permitted in some jurisdictions if the insulation is combustible. C) is never permitted. D) may be more prone to attack by pests than wires above insulation.

The answer is IS NOT PERMITTED IN SOME JURISDICTIONS IF THE INSULATION IS COMBUSTIBLE. Knob-and-tube wiring buried in insulation is not permitted in some jurisdictions if the insulation is combustible.

Disadvantages of pigtailing aluminum to copper wire are A) you can't pigtail different sized wire gauges together. B) it adds more connections and leads to overcrowding boxes. C) the solder isn't likely to be effective. D) the two metals are not compatible.

The answer is IT ADDS MORE CONNECTIONS AND LEADS TO OVERCROWDING BOXES. Pigtailed connections with aluminum wire add more connections to the box and may lead to overcrowding.

Problems with aluminum wiring include all of the following except A) the aluminum oxide is not a good conductor of electricity. B) it lacked a ground wire. C) aluminum is softer than copper and easier to damage. D) it tends to creep.

The answer is IT LACKED A GROUND WIRE. Lacking a ground wire is not a common problem with aluminum wire.

During an inspection you find 20 blown 15-amp fuses beside the panel. You might tell your client A) it's likely that there is at least one overloaded circuit in the panel. B) the 15 amp fuses should be replaced with a larger fuse size that will not blow. C) there must have been several defective fuses purchased, perhaps from one bad lot. D) it's likely that there is a defect in the panel.

The answer is IT'S LIKELY THAT THERE IS AT LEAST ONE OVERLOADED CIRCUIT IN THE PANEL. All of these blown fuses tell you that there is at least one overloaded circuit that continually blows fuses.

What is linking? A) Linking ensures that two fuses or circuit breakers are disconnected at the same time. B) Linking is the same as bonding. C) Linking refers to connections made in a junction box. D) Linking ensures that light switches only operate the fixtures installed in the same room.

The answer is LINKING ENSURES THAT TWO FUSES OR CIRCUIT BREAKERS ARE DISCONNECTED AT THE SAME TIME. Linking ensures that two fuses or circuit breakers are disconnected at the same time. This is important on 240-volt circuits or multi-wire branch circuits.

Putting the fuses upstream of the disconnect switch in the service box A) is a result of installing the box upside-down. B) may cause a short circuit through the fuses. C) is a result of connecting the service conductors to the line side, rather than the load side. D) makes it dangerous to change the fuses even when the house power is shut off.

The answer is MAKES IT DANGEROUS TO CHANGE THE FUSES EVEN WHEN THE HOUSE POWER IS SHUT OFF. Putting fuses upstream of the disconnected switch in the service box makes it more dangerous to change the fuses. Even when the house power is shut off, there will be power to the fuse terminals.

Which statement is correct? A) Neutral and ground wires should be connected at the main panel and separate at subpanels. B) Hot and neutral wires should always be the same color. C) Ground and neutral wires should always be connected. D) Neutral and ground wires should be connected at subpanels and separate at the main panel.

The answer is NEUTRAL AND GROUND WIRES SHOULD BE CONNECTED AT THE MAIN PANEL AND SEPARATE AT SUBPANELS. Neutral and ground wires should be connected at the main panel and separated at sub panels.

All of these are common branch circuit problems except A) open splices. B) NMD wires run through floor joists without tubes or grommets. C) undersized wire. D) damaged wires.

The answer is NMD WIRES RUN THROUGH FLOOR JOISTS WITHOUT TUBES OR GROMMETS. NMD wires run through floor joists without tubes or grommets are not a problem.

All of the following are common outdoor wiring problems except A) unprotected wires within four feet of the garage floor. B) wires running through downspouts. C) garage door openers powered with an extension cord. D) NMW wiring used outdoors.

The answer is NMW WIRING USED OUTDOORS. NMW wire used outdoors is not a problem.

Is it permissible to use an aluminum grounding wire? A) Only if it is at least #3 AWG. B) Yes. C) Only in some provinces and states. D) Only in dry environments in the United States.

The answer is ONLY IN DRY ENVIRONMENTS IN THE UNITED STATES. Aluminum grounding conductors can only be used in dry environments in the United States.

Knob-and-tube wiring issues include all of the following except A) wires buried in insulation. B) connections to modern wire not in boxes. C) overheated neutrals on multi-wire branch circuits. D) brittle wire, insulation, or sheathing.

The answer is OVERHEATED NEUTRALS ON MULTI-WIRE BRANCH CIRCUITS. Overheated neutrals on multi-wire branch circuits are not specific to knob and tube wiring. Multi-wire branch circuits are, in fact, very rare on knob and tube wiring.

Putting a penny in a fuse holder is dangerous because A) the penny will corrode, leading to overheating. B) the penny will melt, causing a short circuit. C) the fuse receptor will react with the copper in the penny, causing it to degrade. D) the circuit has no over-current protection.

The answer is THE CIRCUIT HAS NO OVER-CURRENT PROTECTION. Putting a penny in a fuse holder means that the circuit has no over-current protection.

Three slot receptacles on ungrounded circuits are safety hazards because A) radio devices won't be able to use the ground wire as an antenna. B) computers may not be able to dissipate static charges. C) people may try to put three appliances rather than two into the duplex receptacles. D) people will use grounded appliances, thinking the receptacle is grounded.

The answer is PEOPLE WILL USE GROUNDED APPLIANCES, THINKING THE RECEPTACLE IS GROUNDED. Ungrounded three slot receptacles are a problem because people might use grounded appliances and expect that the receptacle is grounded.

Cables within six feet of an access attic hatch should be A) rated CUAL B) concealed below insulation C) knob-and-tube wiring D) protected from mechanical damage

The answer is PROTECTED FROM MECHANICAL DAMAGE. Cables within six feet of an access attic hatch should be protected from mechanical damage.

A subpanel is supplying a 3-ton air conditioner (running load amps = 18A) and an electric dryer (5000W). The 10 gauge copper subpanel feed wire is connected to a 60A breaker in the main panel. You should A) recommend changing the size of the feed wire to match the breaker. B) recommend changing the size of the breaker to match the feed wire. C) recommend switching to a gas dryer. D) report the installation as okay.

The answer is RECOMMEND CHANGING THE SIZE OF THE FEED WIRE TO MATCH THE BREAKER. The breaker size and the feed wire size should be a match. Alternatively, the wire ampacity should be greater than the breaker rating. The ten gauge copper wire can safely carry 30 amps.

Common branch circuit wire materials include all of these except A) Copper B) Solder-dipped copper C) Aluminum D) Silver-dipped copper

The answer is SILVER-DIPPED COPPER. Silver-dipped copper wires are not made, as far as we know.

How far should wires be kept from the metal vent connector on a gas appliance? A) One inch B) Six inches C) Eighteen inches D) Nine inches

The answer is SIX INCHES. Wires should be kept six inches away from metal vent connectors on a gas appliance.

NMD cable is A) rigid. B) suitable for indoor use. C) armored. D) suitable for outdoor use but not underground.

The answer is SUITABLE FOR INDOOR USE. NMD cable is suitable for dry indoor use.

At the drip loop you notice that the service drop conductors are smaller in diameter than the service entrance conductors. You should conclude A) that the service entrance conductors must be aluminum, and report them as such. B) that this is a normal situation, and is acceptable. C) that the house service must be 200A. D) it was a faulty installation and should be corrected.

The answer is THAT THIS IS A NORMAL SITUATION, AND IS ACCEPTABLE. The service drop conductors can be smaller than the service entrance conductors because the service drop conductors are in free air, whereas the service entrance conductors are in cable or conduit.

All of these are common closet lighting problems except A) bare bulbs are used. B) installing the light above and toward one end of the shelf. C) the light is above a shelf. D) the light is mounted on a wall above the door.

The answer is THE LIGHT IS MOUNTED ON A WALL ABOVE THE DOOR. Mounting the light on a wall above the door in a closet is not a problem.

Which of the following is a safety issue? A) The service box has a higher rating than the service entrance wire. B) The main fuses have a lower rating than the service entrance wire. C) The distribution panel has a larger rating than the service entrance wire. D) The main fuses have a higher rating than the service entrance wire.

The answer is THE MAIN FUSES HAVE A HIGHER RATING THAN THE SERVICE ENTRANCE WIRE. If the main fuses have a higher rating than the service entrance wire, they will not shut off the electricity when the current levels become dangerous. Fire and electrical shock are possible in this situation.

What happens if the neutral wire bypasses the service box? A) The house electrical system won't work properly. B) The ground wire will carry electricity under normal conditions. C) The neutral and grounding system will not be properly connected. D) The grounding electrode conductor can't get to the water piping and/or ground rods.

The answer is THE NEUTRAL AND GROUNDING SYSTEM WILL NOT BE PROPERLY CONNECTED. If the neutral wire bypasses the service box, the neutral and grounding system will not be properly connected to each other.

The term service drop defines A) the wires that connect the meter to the service box. B) the wires that run down the outside of the house into the meter. C) the underground wires from the utility to the point of connection to the house. D) the overhead wires coming from the utility pole to the point of connection to the house.

The answer is THE OVERHEAD WIRES COMING FROM THE UTILITY POLE TO THE POINT OF CONNECTION TO THE HOUSE. The service drop refers to the overhead wires coming from the utility pole to the house.

A house has service entrance conductors designed for 100 amps and a main disconnect rated at 100 amps. Which of these conditions is unsafe? A) The distribution panel is rated at 125 amps. B) The service box is rated at 125 amps. C) The service box is rated at 75 amps. D) The distribution panel is rated at 200 amps.

The answer is THE SERVICE BOX IS RATED AT 75 AMPS. A service box rated at 75 amps is not adequate for 100 amp service.

Which of the following is a reliable way to identify the service size? A) The distribution panel rating B) The size of the service drop wires C) The service entrance conduit size D) The service entrance conductor size

The answer is THE SERVICE ENTRANCE CONDUCTOR SIZE. The best indication of service size is the service entrance wires.

Grounded and grounding conductors must be connected at A) all subpanels. B) the service panel only. C) all possible locations. D) all boxes and panels.

The answer is THE SERVICE PANEL ONLY. Grounded and grounding conductors must be connected at the service panel only.

Which one of the following is a reliable indicator of service amperage? A) The rating of the meter B) The rating of the distribution panel C) The size of the service entrance conductors D) The size of the service drop wires

The answer is THE SIZE OF THE SERVICE ENTRANCE CONDUCTORS. The size of the service entrance conductors is the most reliable indicator of service amperage.

You plug your circuit tester into an outlet that has a washing machine plugged in. Your tester shows the outlet is properly wired and grounded. How could you improve this inspection process? A) Use a circuit tester with a GFI test button B) Use a voltage tester C) Turn the washing machine on before doing your test D) Unplug the washing machine hine.

The answer is UNPLUG THE WASHING MACHINE. Unplugging the washing machine will ensure that your tester doesn't read a false ground connection through the washing mac

Ohm's Law, the relationship between voltage, current, and resistance in a simple circuit, states A) V=I/R. B) V=IR. C) I=VR. D) R=I/V.

The answer is V=IR. V = IR and R= V/I.

The unit for the measure of electrical power is A) watts. B) amps. C) joules. D) kWh.

The answer is WATTS. The unit for the measure of electrical power is watts.

Supports for branch circuit wires are needed A) every 3 feet. B) only where wires may be exposed to mechanical damage. C) only where the wires are run horizontally. D) within 12 inches of leaving a box.

The answer is WITHIN 12 INCHES OF LEAVING A BOX. Branch circuit wires should be supported within 12 inches of leaving a box.

With respect to amperage ratings, the main fuses or breaker A) should be no larger than the rating of the service box. B) must be greater than the service box rating. C) should be sized to adequately protect the service entrance wires and should be no larger than the rating of the service box. D) should be sized to adequately protect the service entrance wires.

The answer is should be sized to adequately protect the service entrance wires and should be no larger than the rating of the service box. The main fuses or breakers should be sized to adequately protect the service entrance wires and should be no bigger than the rating of the service box.

The drip loop is typically part of the service drop. True False

The statement is FALSE. The drip loop is part of the service entrance wires, not the service drop.

All service entrance conductors must be in conduit. True False

The statement is FALSE. The service entrance wires may be in a conduit on the outside of the building or there may be a special Service Entrance (SE) cable that does not require a conduit.

There can be up to ten throws to disconnect all of the electricity in the house. True False

The statement is FALSE. There can be up to six throws to disconnect all of the electricity in the house.