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NEC 2020 Code Questions Practice Test 13

Free NEC 2020 practice test with 30 questions on service equipment, overcurrent protection, motors, and wiring methods. Plain-English questions with full explanations.

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This NEC 2020 Code Questions Practice Test 13 has 30 questions with detailed answers and NEC references. Take the full test, review every wrong answer, and look up the NEC article it references before moving on.

Tip: Mixed-format test — questions jump between topics just like the real exam. Don't spend more than 90 seconds on any one question.

Topics covered: All NEC chapters — branch circuits, grounding, conductors, wiring methods, motors, and more.
Passing score: Aim for 80%+ consistently before scheduling your exam.
Questions: 30 multiple-choice, one correct answer each

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45 min

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NEC 2020 Code Questions Practice Test 13 — Question List

Question 1: The dedicated space above a panelboard, up to 6 feet high, must be kept clear of:

Foreign systems, such as plumbing
Fresh air
Light
Nothing, it has no rule

NEC Reference: NEC 110.26(E)(1)

Question 2: A building has a ground rod and a concrete-encased electrode. What must be done with both electrodes?

Bond them together into one system
Use only one and ignore the other
Keep them fully separate
Remove one of them

NEC Reference: NEC 250.50

Question 3: The main bonding jumper connects the grounded conductor to the equipment grounding path at:

The service equipment
Every downstream panel
The last outlet on the circuit
The utility pole

NEC Reference: NEC 250.28

Question 4: Overcurrent devices, such as breakers, must be located where they are:

Readily accessible
Locked away with no key
Buried in concrete
It does not matter

NEC Reference: NEC 240.24(A)

Question 5: Overcurrent devices are generally not permitted to be installed in which dwelling room?

Bathrooms
Garages
Basements
Utility rooms

NEC Reference: NEC 240.24(E)

Question 6: A cartridge fuse must be marked with the ampere rating and:

Voltage rating
The buyer's name
Nothing else
The store where it was purchased

NEC Reference: NEC 240.60(D)

Question 7: Service equipment must be:

Listed and marked for service use
Homemade
Unmarked
Made of wood

NEC Reference: NEC 230.66

Question 8: A service raceway exposed to the weather must be:

Rain-tight and drained
Left open on top
Made of wood
It does not matter

NEC Reference: NEC 230.53

Question 9: As a general rule, how many services can supply one building?

Only one
Two, always
As many as needed
No limit

NEC Reference: NEC 230.2

Question 10: Where more than one service disconnect is grouped at one place, each one must be:

Marked to show what it supplies
Left unlabeled
Painted one color with no labels
Hidden from view

NEC Reference: NEC 230.72(A)

Question 11: A motor disconnect must have an ampere rating of at least what percent of the motor full-load current?

100 %
115 %
125 %
150 %

NEC Reference: NEC 430.110(A)

Question 12: Feeder conductors supplying several motors must be sized using the highest-rated motor at 125%, plus:

The full-load currents of the other motors
Nothing else
A flat 10 amperes
The building square footage

NEC Reference: NEC 430.24

Question 13: Overcurrent protection sizing rules for transformers are found in:

NEC 450.3
NEC 90.1
NEC 300.1
No rule applies to transformers

NEC Reference: NEC 450.3

Question 14: A fixed (non-portable) generator must have:

A disconnecting means
No disconnect at all
A padlock only, no switch
A fire extinguisher only

NEC Reference: NEC 445.18

Question 15: A portable generator that only supplies equipment mounted on the generator itself needs:

No separate grounding electrode
A dedicated ground rod every time
No grounding is ever allowed
A bond to gas piping

NEC Reference: NEC 250.34(A)

Question 16: Class II hazardous locations (combustible dust) are divided into which groups?

Groups E, F, and G
Groups A, B, C, and D
Groups 1 and 2
There are no groups

NEC Reference: NEC 500.6(B)

Question 17: A Class I, Division 1 location is one where a flammable gas is expected to be present:

During normal operation
Only during equipment failure
Never
Only outdoors

NEC Reference: NEC 500.5(B)(1)

Question 18: A mobile home service disconnect must have a minimum rating of:

30 amperes
50 amperes
100 amperes
200 amperes

NEC Reference: NEC 550.32(A)

Question 19: A flexible cord for a pool pump motor must not be longer than:

3 feet
6 feet
10 feet
15 feet

NEC Reference: NEC 680.21

Question 20: The disconnect for an elevator must be located:

Within sight of the motor controller
Anywhere in the building
On the roof only
It is never required

NEC Reference: NEC 620.51

Question 21: Emergency power systems must be tested from time to time, and a record kept by:

The building owner
The local fire department
The power company
No testing is required

NEC Reference: NEC 700.3

Question 22: Which of these is a wiring method permitted for service-entrance conductors?

Rigid metal conduit
Open knob-and-tube wiring
Bare wire in open air
A garden hose

NEC Reference: NEC 230.43

Question 23: Rigid metal conduit (RMC) must be supported at intervals not more than:

5 feet
10 feet
15 feet
20 feet

NEC Reference: NEC 344.30

Question 24: Liquidtight flexible metal conduit is often used to connect:

Motors and vibrating equipment
Overhead service drops only
Nothing, it has no listed use
Underground burial with no conduit

NEC Reference: NEC 350.10

Question 25: Type UF cable is designed for:

Direct burial underground
Indoor use only
It has no permitted use
Telephone wiring only

NEC Reference: NEC 340.10

Question 26: Type AC (armored) cable is generally permitted for:

Dry, indoor locations
Wet locations with no protection
Underground burial with no protection
It has no permitted use

NEC Reference: NEC 320.10

Question 27: Compared to Type AC cable, Type MC cable is permitted in a wider range of uses, including:

Direct burial, when listed for it
It has no listed uses
Indoor dry attics only
Grounding purposes only

NEC Reference: NEC 330.10

Question 28: A long run of PVC conduit needs an expansion fitting when the expected length change is more than:

1/4 inch
2 inches
6 inches
1 foot

NEC Reference: NEC 352.44

Question 29: Outlet boxes must have enough depth to fit the equipment inside, generally not less than:

1/2 inch
4 inches
1/8 inch
There is no minimum

NEC Reference: NEC 314.24

Question 30: Boxes and conduit bodies must be installed so the wiring can be reached without:

Removing part of the building
This is never a concern
Tearing down the whole wall
It does not matter

NEC Reference: NEC 314.29

NEC 2020 Code Questions Practice Test 13

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NEC 2020 Code Questions Practice Test 13

How this test works

How to Use This Practice Test

Student Reviews

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NEC 2020 Code Questions Practice Test 13 — Question List

Question 1: The dedicated space above a panelboard, up to 6 feet high, must be kept clear of:

Question 2: A building has a ground rod and a concrete-encased electrode. What must be done with both electrodes?

Question 3: The main bonding jumper connects the grounded conductor to the equipment grounding path at:

Question 4: Overcurrent devices, such as breakers, must be located where they are:

Question 5: Overcurrent devices are generally not permitted to be installed in which dwelling room?

Question 6: A cartridge fuse must be marked with the ampere rating and:

Question 7: Service equipment must be:

Question 8: A service raceway exposed to the weather must be:

Question 9: As a general rule, how many services can supply one building?

Question 10: Where more than one service disconnect is grouped at one place, each one must be:

Question 11: A motor disconnect must have an ampere rating of at least what percent of the motor full-load current?

Question 12: Feeder conductors supplying several motors must be sized using the highest-rated motor at 125%, plus:

Question 13: Overcurrent protection sizing rules for transformers are found in:

Question 14: A fixed (non-portable) generator must have:

Question 15: A portable generator that only supplies equipment mounted on the generator itself needs:

Question 16: Class II hazardous locations (combustible dust) are divided into which groups?

Question 17: A Class I, Division 1 location is one where a flammable gas is expected to be present:

Question 18: A mobile home service disconnect must have a minimum rating of:

Question 19: A flexible cord for a pool pump motor must not be longer than:

Question 20: The disconnect for an elevator must be located:

Question 21: Emergency power systems must be tested from time to time, and a record kept by:

Question 22: Which of these is a wiring method permitted for service-entrance conductors?

Question 23: Rigid metal conduit (RMC) must be supported at intervals not more than:

Question 24: Liquidtight flexible metal conduit is often used to connect:

Question 25: Type UF cable is designed for:

Question 26: Type AC (armored) cable is generally permitted for:

Question 27: Compared to Type AC cable, Type MC cable is permitted in a wider range of uses, including:

Question 28: A long run of PVC conduit needs an expansion fitting when the expected length change is more than:

Question 29: Outlet boxes must have enough depth to fit the equipment inside, generally not less than:

Question 30: Boxes and conduit bodies must be installed so the wiring can be reached without:

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