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Electriciansparadise -- Archived Questions

1. NEC 2005 does not cover wiring in underground structures.

A. True

B. False


Answer: B. False

Wiring underground in mines is not covered. Other underground wiring (such as in non-mine tunnels) is covered.


2. A bathroom is defined as an area including:

A. A basin.

B. A basin and a toilet.

C. A basin and a tub or shower.

D. B and C.


Answer: D. B and C.

It is important to know what area (not necessarily a discrete room) constitutes a bathroom for many design decisions that have to be made. For example, overcurrent devices are not permitted in a bathroom, so its no place for a service or feeder termination.


3. A system bonding jumper

A. is the same as a main bonding jumper.

B. occurs at a seperately derived system.

C. is optional for a 120/240 volt single-phase system.

D. is always required.


Answer: B. occurs at a seperately derived system.

Multiple separately derived systems are frequently found in large occupancies. Each of these must have ground electrodes and a system bonding jumper.


4. A general purpose branch circuit

A. supplies only receptacles.

B. has overcurrent protection at both ends.

C. supplies two or more receptacles or outlets for lighting and appliances.

D. supplies only one utilization equipment.


Answer: C. supplies two or more receptacles or outlets for lighting and appliances.

All receptacles that are wired in place are outlets but all outlets are not receptacles. A ceiling light is an outlet, as is a 100-HP motor wired in place.


5. A multiwire branch circuit

A. has at least three wires in addition to the equipment grounding conductor.

B. is more costly but provides an additional level of safety.

C. can be used only for 15- and 20-amp single phase systems.

D. cannot be used in dwellings.


Answer: A. has at least three wires in addition to the equipment grounding conductor.

Multiwire branch circuits must be installed with great care because if both hot wires are put on the same leg, the neutral can be overloaded and not protected by the correct overcurrent device.


6. A continuous load is a load where the maximum current is expected to continue for _ hours or more.

A. two

B. three

C. four

D. five


Answer: B. three

Various types of equipment are characterized in NEC as continuous loads due to the nature of their use. An example is electric heat, since on a cold day it can be expected to run for over three hours without interruption.


7. A dwelling unit

A. provides living facilities for two or more persons.

B. includes hotel rooms only if they have provisions for cooking.

C. may always be wired with type NM cable.

D. does not include mobile homes.


Answer: B. includes hotel rooms only if they have permanent provisions for cooking.

It is important to understand the exact definition of dwelling because many NEC requirements vary according to occupancy.


8. A main bonding jumper must be connected between the grounded conductor and the equipment grounding conductor

A. at the service only.

B. at each final overcurrent device enclosure.

C. A and B.

D. neither A nor B.


Answer: A. at the service only.

It is very common to see in the work of untrained individuals extra bonding of grounded and grounding conductors beyond the service enclosure. These two conductors should be bonded only at the service enclosure, never to rejoin. Improper multiple bonding causes objectionable circulating current to flow.


9. A volatile flammable liquid has a flash point

A. below 100 degrees F.

B. above 100 degrees F.

C. below 75 degrees F.

D. above 100 degrees F.


Answer: A. Below 100 degrees F.

Wiring in the presence of volatile flammable liquids must comply with NEC Chapter 5 provisions.


10. Termination provisions of equipment for circuits rated 100 amperes or less, or marked for 14 AWG through 1 AWG conductors shall be used for

A. conductors rated 60 degrees C.

B. conductors with higher temperature ratings, provided the ampacity of such conductors is determined based on the 60 degree C. ampacity of the conductor size used.

C. conductors with higher temperature ratings if such equipment is listed and identified for use with such conductors.

D. any of the above.


Answer: D. any of the above.

In addition, for motors marked with design letters B, C, or D, conductors having an insulation rating of 75 degrees C. or higher shall be permitted to be used, provided the ampacity of such conductors does not exceed the 75 degree C. ampacity.


11. Termination provisions of equipment for circuits rated over 100 amperes or marked for conductors larger than 1 AWG, may be used for one of the following

A. conductors rated under 75 degrees C.

B. conductors rated over 75 degrees C.

C. conductors rated 75 degrees C.

D. conductors rated 90 degrees C.


Answer: C. conductors rated 75 degrees C.

These termination provisions may also be used with conductors with higher temperature ratings, provided the ampacity of such conductors does not exceed the 75 degree C. ampacity of the conductor size used, or up to their ampacity if the equipment is listed and identified for use with such conductors.


12. Field marking of panelboards to warn qualified persons of potential electric arc flash hazard is required in

A. other than dwelling occupancies.

B. dwelling occupancies.

C. all occupancies.

D. only transformer rooms.


Answer: A. other than dwelling units.

Field marking of switchboards, industrial control panels, meter socket enclosures and motor control centers is also required.


13. Which of the following is true?

A. Service entrance conductors always include the service conductors.

B. Service entrance conductors end at the meter.

C. Service entrance conductors are from the meter to the entrance panel.

D. Service entrance conductors extend from the service point to the service disconnecting means.


Answer: D. Service entrance conductors extend from the service point to the service disconnecting means.

It is important to understand the exact definition of service conductors because, since they are fused at much higher ampacities than feeder or branch circuit wiring, a higher level of physical protection is required.


14. On a 4-wire, delta-connected system where the midpoint of one phase winding is grounded, only the conductor or busbar having the higher phase voltage to ground shall be durably and permanently marked by an outer finish that is ___ in color or by other effective means.

A. red

B. orange

C. yellow

D. white


Answer: B. orange

When working with this type of system, it is necessary to check all legs with a voltmeter to determine which is the high leg. This identification shall be placed at each point on the system where a connection is made if the grounded conductor is present.


15. The ___ of working space is specified in 110.26 (A).

A. depth

B. width

C. height

D. All of the above.


Answer: D. All of the above.

In designing a large electrical installation, misapplication of 110.26 could be a costly error.


16. Which of the following is true?

A. The 30" wide working space must be centered on the equipment in question.

B. The 30" wide working spaces of two adjacent panels may not overlap.

C. If the equipment is wider than 30" the working space has to be equal to the equipment.

D. A panel door must be able to open all the way.


Answer: C. If the equipment is wider than 30" the working space has to be equal to the equipment.

If adequate working space is not provided, worker safety is compromised.


17. Which of the following is false?

A. If the nominal voltage to ground is 0-150, minimum clear distance is the same for all conditions.

B. If the minimum voltage to ground is 151-600, minimum clear distance is the same for all conditions.

C. Condition 3 is when there are exposed live parts on both sides of the working space.

D. Tile walls should be considered as grounded.


Answer: B. If the minimum voltage to ground is 151-600, minimum clear distance is the same for all conditions.

Few electricians have all of these provisions memorized, but they can be accessed easily in 110.26.


17. The minimum headroom of working space about service equipment, switchboards, panelboards or motor control centers shall be ___ .

A. 6'

B. 6.5'

C. 7'.

D. 8'.


Answer: B. 6.5'.

An exception exempts existing dwelling units where service equuipment or panelboards not over 200 amps require less than 6.5' headroom.


18. Dedicated electrical space ___ .

A. Pertains only to service equipment.

B. Is equal to the width and depth of the equipment and extends to a height of 6' above the equipment or to the structural ceiling, whichever is lower.

C. May not contain suspended ceilings.

D. May contain sprinkler systems.


Answer: B.Is equal to the width and depth of the equipment and extends to a height of 6' above the equipment or to the structural ceiling, whichever is lower .

Sprinkler protection may be afforded the dedicated electrical space but the piping and heads have to be outside of it.


19. NEC 2005 110.26 contains provisions regarding __ .

A. working space about electrical equipment.

B. dedicated equipment space.

C. both A. and B.

D. neither A. nor B.


Answer: C. both A. and B.

A mistake in applying these provisions could be very costly.


20. Round access openings in a manhole shall not be less than ___ inches in diameter.

A. 24

B. 26

C. 28

D. 30


Answer: B. 26

A fixed ladder or only low voltage wiring reduce the minimum diameter to 24 inches.


21. Only one entrance to indoor working space is required if ___.

A. the equipment is rated less than 1200 amps

B. the exit way is continuous and unobstructed

C. depth of working space is doubled

D. any of the above


Answer: D. any of the above

If the entrance has a door, it must open outward and have panic bar hardware or similar. These requirement often pertain to a room, but the locations could be within a large open area. Additionally, NEC specifies requirements for transformer rooms and transformer vaults, which have other requirements besides working space and dedicated space which always apply.


22. Working space and dedicated space for equipment ___.

A. are found in the same article.

B. have different puposes

C. have different numbers

D. All of the above


Answer: D. All of the above.

Most electricians' exams have at least one question on each of these concepts. Since they are usually open book, it is easy to score correct answers because the material is all in one place.


23. Article 210 covers branch circuits that supply only motor loads.

A. True

B. False


Answer: B. False.

Branch circuits that supply motor loads exclusively are covered in Article 430. The procedures for overcurrent protection and short circuit and ground fault protection are totally different.


24. A grounded conductor larger than 6 AWG shall be identified by ___.

A. a continuous white or gray outer finish.

B. three continuous white stripes.

C. a white or gray marking at terminations that encircles the conductor or insulation.

D. Any of the above


Answer: D. any of the above

Sizes 6 AWG and smaller are not permitted to be identified only at terminations except for mineral insulated, metal sheathed cable and in photovoltaic systems.


25. In dwelling units all 125-volt, single-phase, 15- and 20-ampere receptacles in ___ shall have GFCIs.

A. bathrooms

B. garages

C. outdoors

D. All of the above


Answer: D. all of the above

The requirement for bathrooms has no exceptions. Other required locations are in 210.8. In dwellings, kitchens require GFCIs where they serve countertop surfaces. In nondwellings GFCIs are required throughout the entire kitchen.


26. In dwellings, GFCIs are required for laundry, utility and wetbar sinks where the receptacles are within ___ feet of the outside edge of the sink.

A. 4

B. 5

C. 6

D. 8


Answer: C. 6

The answers to GFCI questions are easy to find if you have a set of Code tabs. They are in Article 210 - Branch Circuits.


27. Which of the following is true?

A. Arc fault circuit interrupters are required on all 120-volt, single-phase 15- and 20-ampere circuits in dwellings.

B. Arc fault circuit interrupters are optional in hotel rooms.

C. Arc fault circuit interrupters are optional until January 1, 2008.

D. All of the above.


Answer: B. Arc fault circuit interrupters are optional in hotel rooms.

Circuits that supply smoke detectors in bedrooms of dwellings are among those that must be arc fault protected.


28. For ranges of ___ kW or more rating, the minimum branch circuit rating shall be 40 amperes.

A. 7 3/4

B. 8

C. 8 1/2

D. 8 3/4


Answer: D. 8 3/4

An exception allows smaller tap conductors no longer than necessary for servicing the appliance.


29. A GFCI requires an equipment grounding conductor to operate properly.

A. True

B. False


Answer: B. False

A GFCI may be used as a replacement for an old two wire receptacle. A "no equipment ground" label must be attached.


30. Tap conductors supplying electric ranges, wall-mounted electric ovens, and counter-mounted electric cooking units from a 50-ampere branch circuit shall have an ampacity of not less than ___ and shall be sufficient for the load to be served.

A. 15

B. 20

C. 30

D. 40


Answer: B. 20

Electricians' exams invariably have questions on the various tap rules. These questions can be difficult because the tap rules are not all in one place. The NEC Index helps make sense of all this. Also Ferm's Fast Finder, which is allowed in some states' open book exams, is helpful in accessing tap rules quickly.


31. The rating for the overcurrent device for a branch circuit that supplies a continuous load shall not be less than ___ percent of that load.

A. 80

B. 100

C. 115

D. 125


Answer: D. 125

A continous load is one that is expected to operate for three hours or more. These include electric heat and commercial lighting among others.


32. Tap conductors shall have an ampacity of not less than 15 for circuits rated less than ___.

A. 20

B. 30

C. 40

D. 50


Answer: C. 40

For 40 or 50 amp circuits, the tap conductors must not be less than 20 amp.


33. a single receptacle installed on a 20 amp individual branch circuit must have a rating not less than ___ amps.

A. 15

B. 20

C. 30

D. Not specified


Answer: B. 20

A single receptacle installed on an individual branch circuit must have a rating not less than that of the branch circuit.


34. The rating of any one cord-and-plug connected utilization equipment not fastened in place shall not exceed ___ percent of the branch-circuit ampere rating.

A. 60

B. 75

C. 80

D. 100


Answer: C. 80

Most such equipment does not exceed 16 amps and so a 20 amp circuit is compliant.


35. For a two-family or multifamily dwelling, common areas may be fed from a dedicated circuit within one of the dwelling units.

A. True

B. False


Answer: B. False

Loads in a public or common area must have their own panel outside any of the dwelling units.


36. Appliance receptacle outlets installed in a dwelling unit for specific appliances, such as laundry equipment, shall be installed within ___ ft. of the intended location of the appliance.

A. 4

B. 5

C. 6

D. 8


Answer: C. 6

An overabundance of cordage is a big cause of fires.


37. Permanently installed electric baseboard heaters equipped with factory-installed receptacle outlets or outlets provided as a separate assembly by the manufacturer shall be permitted as the required outlet or outlets for the wall space utilized by such permanently installed heaters. Such receptacles shall not be connected to the heater circuits.

A. True

B. False


Answer: True

Listed baseboard heaters include instructions that may not permit their installation below receptacle outlets.


38. In every kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedroom, recreation room or similar room or area of dwelling units, receptacles shall be installed so that no point measured horizontally along the floor line in any wall space is more than ___ ft. from a receptacle outlet.

A. 4

B. 6

C. 8

D. 10


Answer: B. 6

This requirement does not apply to bathrooms or hallways, which have their own rules. It does not apply also to commercial or industrial occupancies in which, rather than spacing, they are placed as needed.


39. The neutral conductor of a 3-wire branch circuit supplying a household electric range, a wall-mounted oven or a counter-mounted cooking unit shall be permitted to be smaller than the ungrounded conductors where the maximum demand of a range of 8 3/4 KW or more rating has been calculated according to Column C of Table 220.55, but such conductor shall have an ampacity of not less than ___ percent of the branch circuit rating and shall not be smaller than 10 AWG.

A. 50

B. 60

C. 70

D. 80


Answer: C. 70

This reduced neutral is for a 240-volt household range. It is allowed because the only line-to-neutral loads are timer, clock, lights and sometimes a heating element on low.


40. A refrigerator outlet in the kitchen of a dwelling may be connected to one of the 20-amp small appliance circuits or to a 15-amp or larger branch circuit.

A. True

B. False


Answer: A. True

Refrigeration equipment is not required to be GFCI protected. Refrigeration is often considered incompatible with GFCI's because of frequent nuisance tripping. If power is interrupted for a period of time, food spoilage can occur.


41. In kitchens and dining rooms of dwelling units, receptacle outlets for counterspaces shall be installed at each counterspace that is ___ inches or wider.

A. 8

B. 10

C. 12

D. 16


Answer: C. 12

These receptacles have to be fed by at least two 20-amp small appliance branch circuits.


42. Laundry areas in dwellings shall have at least ___ receptacle(s) supplied by a 20-amp branch circuit.

A. 1

B. 2

C. 3

D. Not specified


Answer: A. 1

The 20-amp branch circuit can have no other outlets, i.e. outside the laundry.


43. Information technology rooms are required ___.

A. in commercial and industrial settings

B. where four or more computers are connected to the same UPS

C. in fire-rated buildings

D. never


Answer: D. never

Information technology rooms are optional and allow cost-saving reductions in required wiring methods and materials.


44. A 125-volt, single-phase, 15- or 20-amp receptacle outlet shall be installed at an accessible location for the servicing of heating, air conditioning and refrigeration equipment. The receptacle shall be on the same level and within ___ feet of the equipment.

A. 15

B. 20

C. 25

D. 50


Answer: C. 25

The receptacle outlet shall not be connected to the load side of the equipment disconnecting means.


45. Where are wall switch-controlled lighting outlets required?

A. Every habitable room and bathroom in dwelling units.

B. Hallways and stairways in dwellings.

C. Attached garages and detached garages with electric power.

D. All of the above.


Answer: D. All of the above.

For interior stairways there shall be a wall switch at each floor level where the stairway has six risers or more.


46. Unless other voltages are specified, for purposes of calculating branch-circuit and feeder loads, nominal system voltages of 120, 120/240, 208Y/120, 240, 347, ___ , 480, 600Y/347 and 600 volts shall be used.

A. 420

B. 277

C. 480Y/277

D. 547


Answer: C. 480Y/277

A three-phase panel can also supply single-phase loads.


47. The general lighting load for a dwelling is ___ volt-amperes per square foot of floor area.

A. 2

B. 3

C. 4

D. 5


Answer: B. 3

Floor area is calculated from the outside dimensions of the building. For dwellings, open porches, garages and unused or unfinished spaces not adaptable for future use are not included.


48. Generally, in dwelling occupancies, receptacle outlets do not have to be counted in addition to the general lighting load for branch-circuit, feeder and service calculations.

A. True

B. False


Answer: A. True

In other occupancies, receptacle outlets have to be calculated separately and added to the general lighting load given in Table 22.12.


49. For show window lighting, a load of not less than ___ volt amperes per lineal foot shall be included.

A. 150

B. 200

C. 250

D. 300


Answer: B. 200

This measurement is taken horizontally along the base.


50. For track lighting in other than dwelling units or guest rooms or guest suites of hotels and motels, a load of ___ shall be included for every two feet of lighting track or fraction thereof.

A. 150

B. 200

C. 250

D. 300


Answer: A. 150

Where multicircuit track is installed, the load shall be considered to be divided equally between the track circuits.


51. For dwelling units a ___ % demand factor may be applied to that portion of the lighting load from 3001 to 120,000 volt-amps.

A. 25

B. 35

C. 40

D. 50


Answer: B. 35

A 25% demand factor may be applied to the remainder of the load over 120,000 volt-amps.


52. For non-dwelling receptacle loads a ___ % demand factor may be applied for the portion of the load over 10 KVA.

A. 25

B. 35

C. 40

D. 50


Answer: D. 50

Since the receptacle load for dwellings is included in the general lighting load, no separate demand factor is given.


53. Fixed electric space heading loads shall be calculated at ___ % of the total connected load.

A. 75

B. 80

C. 100

D. 125


Answer: C. 100

In no case shall a feeder or service load current rating be less than the rating of the largest branch circuit supplied.


54. In each dwelling unit, the load shall be calculated at ___ volt-amperes for each two-wire small appliance branch circuit required by 210.11 (c) (1).

A. 1000

B. 1500

C. 2000

D. 2500


Answer: B. 1500

This load shall be permitted to be included with the general lighting load and subjected to the demand factors provided in Table 220.42.


55. A load of not less than ___ volt-amps shall be included for each two-wire laundry branch circuit installed as required by 220.11 (c) (2).

A. 1000

B. 1500

C. 2000

D. 2500


Answer: B. 1500

This load shall be permitted to be included with the general lighting load and subjected to the demand factors provided in Table 220.42.


56. It shall be permissable to apply a demand factor of ___ % to the nameplate rating of four or more appliances fastened in place, other than electric ranges, clothes dryers, space heating equipment, or air-conditioning equipment, that are served by the same feeder or service in a one-family, two-family or multi-family dwelling.

A. 50

B. 60

C. 75

D. 8O


Answer C. 75.

Demand factors for household electric clothes dryers and kitchen equipment in dwellings are provided for separately and are slightly less than the above.


57. The load for electric clothes dryers in a dwelling unit(s) shall be either ___ volt-amps or the nameplate rating, whichever is higher.

A. 2000

B. 3000

C. 4000

D. 5000


Answer: D. 5000

The use of demand factors in Table 220.54 is permitted.


58. Where it is unlikely that two or more noncoincident loads will be in use simultaneously, it shall be permissable to use only the largest load(s) that will be used at one time for calculating the total load of a feeder or service.

A. True.

B. False.


Answer: A. True.

The classic example of noncoincident loads is heating and air conditioning.


Books for electricians --

Here is a selection of the most significant electricians' books available online today, at the best prices around. Clicking on any logo provides access to reviews and ratings by electricians. A good place to start is with the 2008 NEC Handbook, which contains the complete text of the current code plus extensive commentary, diagrams and illustrations. Other books of interest for the electrician are available as well.

Low Voltage, Telecom, Fire Alarm Books --


HOME | Best Web Host | Question of the Week | Archived Questions | More Archived NEC Questions | Still More Archived Questions | Still More Archived Questions-2 | Still More Archived Questions-3 | Articles | Electrical Deficiencies | More Electrical Deficiencies | Electricians Tools | Online computers | Cybercorner | Electrician's License | Electronics Tutorials | Electricians' worksaving ideas | Electronic Theorems | Satellite Dish | Digital Cameras and Equipment | HTML Color Chart | Electronic Acronyms | Electronic Definitions | Electrician's Soldering Tutorial | Photovoltaic Power | Wind Power | Fire Alarm Basics | More Fire Alarm Info | Working with MC and EMT | Electricians' Color Code | Wiring Commercial Garages | Managing Your Emergency Lights | Lighting Design | Industrial Wiring | Wiring Ethernet | Residential Wiring | Low Voltage Wiring | PLC Overview | Electrical Troubleshooting Techniques | Using Loop Impedance Meter | Ten Common Grounding Errors |NEC and Low-Voltage Wiring | Raceway Protection and NEC | Working with Metal Raceway | Inductance and Characteristic Impedance | Understanding Capacitance | History of the Ethernet | Twisting Data Conductors | NEC Article 800, Communications Circuits | NEC Article 810, Radio and Television Equipment | NEC Article 820, Community Antenna and Radio Distribution Equipment | NEC Article 830, Network-Powered Broadband | Troubleshooting Submersible Well Pumps | Wiring Healthcare Facilities | First Edition National Electrical Code 1897 | Books for Electricians | Links



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