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MASTER NEC 2023

Master Electrician Practice Test 29 – General Requirements & Working Space

This is Master Electrician Practice Test 29 — General Requirements & Working Space, a deeper dive into NEC Article 110 beyond the basic clearance depths — covering entrances, illumination, arc flash labeling, and the rules that apply across nearly every other article in the code. The test has 25 multiple-choice questions on working space by voltage tier, large equipment entrances, illumination requirements, hazard marking, and general installation quality rules. Pass score is 70%. Every question includes a full NEC 2023 explanation so you can trace each answer back to the exact code section.

TOPICS COVERED

General Requirements & Working Space

How this test works

Read each question carefully

Look for absolute words like always / never — they often distinguish the right answer.

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Frequently Asked Questions

Yes — completely free with no signup required. All answers include detailed explanations.

Requirements vary by state but typically include 4–8 years of documented electrical work experience plus a valid Journeyman license.

Advanced NEC code interpretation, load calculations, service entrance design, motor controls, generator systems, and electrical system design.

The Master exam focuses more on design, calculations, and planning rather than installation details. Load calculation and service sizing questions are weighted heavily.

Before You Start

25 questions — multiple choice
45 minutes to finish (timer starts when you begin)
Pass score is 70% — you need at least 18 correct answers
Full NEC 2023 explanation shown for every question after you submit

Topics in This Test

Working space depth at 0-150V — a flat 3 ft for all three conditions (NEC Table 110.26(A)(1))
Working space depth at 601-1000V — 3/4/5 ft by condition (NEC Table 110.26(A)(1))
Working space width — 30 in or the equipment's width, whichever is greater (NEC 110.26(A)(2))
Arc flash hazard warning label requirement (NEC 110.16)
Field-applied hazard markings must be durable and suited to the environment (NEC 110.21(B))
Neat and workmanlike installation requirement (NEC 110.12)
Unused openings in enclosures must be closed (NEC 110.12(A))
Enclosure types matched to the installation environment (NEC Table 110.28)
Definition of a "qualified person" (NEC Article 100)
Dedicated equipment space — floor to 6 ft above equipment or the structural ceiling, whichever is lower (NEC 110.26(F)(1)(a))
Working space must be kept clear, not used for storage (NEC 110.26(B))
Large equipment (1200A+, over 6 ft wide) needs two entrances (NEC 110.26(C))
Entrance dimensions — at least 24 in wide, 6.5 ft high (NEC 110.26(C))
Single-entrance exception — unobstructed egress and doubled depth clearance (NEC 110.26(C))
Illumination required for indoor working spaces (NEC 110.26(D))
Illumination cannot be controlled by automatic means only (NEC 110.26(D))
Illumination exception — adjacent lighting already covering the space (NEC 110.26(D))
Scenario — storage boxes blocking a panel's working space
Scenario — large equipment with only one entrance and no egress exception
Purpose of the two-entrance rule — a safe escape route during an arc-flash event
How working space requirements scale with voltage
Scope of Article 110 — general requirements across the whole NEC
Why arc flash labels target equipment likely to be serviced while energized
Comparing all three Table 110.26(A)(1) voltage tiers side by side
Why Article 110 is considered the NEC's general requirements article

Tip: Article 110's working space rules exist for one reason: giving a person room to work on energized equipment safely and get away quickly if something goes wrong. Every specific number in Table 110.26 — depth, width, entrances, illumination — traces back to that single goal.

Questions

45 min

Time

70%

Pass

Timer starts immediately. Progress is auto-saved.

Master Electrician Practice Test 29 – General Requirements & Working Space — Question List

Question 1: For equipment operating at 150V to ground or less, what working space depth does NEC Table 110.26(A)(1) require, across all three conditions?

A flat 3 ft, for all three conditions
3/3.5/4 ft depending on condition
3/4/5 ft depending on condition
No depth requirement applies below 150V

NEC Reference: NEC Table 110.26(A)(1)

Question 2: For equipment operating at 601 to 1000V, what working space depths does NEC Table 110.26(A)(1) require for Conditions 1, 2, and 3?

3 ft / 3.5 ft / 4 ft
3 ft / 4 ft / 5 ft
2 ft / 3 ft / 4 ft
A flat 3 ft, same as the lowest voltage tier

NEC Reference: NEC Table 110.26(A)(1)

Question 3: NEC 110.26(A)(2) requires the width of a working space to be:

At least 30 in, or the width of the equipment, whichever is greater
Exactly 12 in, regardless of equipment size
Exactly the width of the equipment, with no minimum
There is no width requirement in the NEC

NEC Reference: NEC 110.26(A)(2)

Question 4: NEC 110.16 requires an arc flash hazard warning label on which type of equipment?

Equipment likely to be examined, adjusted, or serviced while energized
Only equipment that is never opened after installation
Only equipment installed outdoors
No equipment requires any such label

NEC Reference: NEC 110.16

Question 5: NEC 110.21(B) requires field-applied hazard markings to be:

Durable and suited to the environment where they are installed
Written only in pencil
Optional and not actually required to be legible
Removed within 30 days of installation

NEC Reference: NEC 110.21(B)

Question 6: NEC 110.12 requires electrical installations to be:

Neat and workmanlike
As fast as possible, regardless of appearance
Hidden from any future inspection
Exempt from any quality standard

NEC Reference: NEC 110.12

Question 7: NEC 110.12(A) requires unused openings in an enclosure to be:

Closed, to maintain the enclosure's intended protection
Left open for future ventilation
Enlarged for easier future access
Ignored, since enclosures have no real protective purpose

NEC Reference: NEC 110.12(A)

Question 8: NEC Table 110.28 provides enclosure type ratings so that an installer can:

Match the enclosure type to the actual installation environment
Select decorative paint colors for equipment
Determine the enclosure's selling price
Ignore environmental conditions entirely

NEC Reference: NEC Table 110.28

Question 9: Per NEC Article 100, a "qualified person" is defined as someone who:

Has skills/knowledge related to the equipment and training to recognize its hazards
Holds any job title containing the word "electrician"
Has never touched electrical equipment before
Is defined only by years of age, with no training component

NEC Reference: NEC Article 100

Question 10: NEC 110.26(F)(1)(a) extends the dedicated equipment space above a piece of electrical equipment up to:

6 ft above the equipment, or the structural ceiling, whichever is lower
Exactly 20 ft, regardless of the ceiling height
There is no upper limit to the dedicated space
1 ft above the equipment only

NEC Reference: NEC 110.26(F)(1)(a)

Question 11: NEC 110.26(B) requires the working space around electrical equipment to be:

Kept clear and not used for storage
Used as general storage space whenever convenient
Reduced to zero once the equipment is installed
Exempt from any clearance requirement after final inspection

NEC Reference: NEC 110.26(B)

Question 12: NEC 110.26(C) requires large equipment rated 1200A or more and over 6 ft wide to have:

Two entrances to the working space
No entrance requirement of any kind
Exactly one entrance, with no exception
Five entrances minimum

NEC Reference: NEC 110.26(C)

Question 13: Under NEC 110.26(C), each entrance to a large equipment working space must be at least:

24 in wide, 6.5 ft high
12 in wide, 3 ft high
48 in wide, 8 ft high
There is no minimum size for an entrance

NEC Reference: NEC 110.26(C)

Question 14: Under NEC 110.26(C), a single entrance is permitted for large equipment when:

There is unobstructed egress travel and the working space depth is doubled
The equipment is painted a specific color
The equipment is rated under 15A
No exception to the two-entrance rule ever exists

NEC Reference: NEC 110.26(C)

Question 15: NEC 110.26(D) requires illumination for indoor working spaces around which type of equipment?

Service equipment, switchboards, panelboards, and motor control centers
Only equipment installed outdoors
Only equipment rated under 15A
No equipment requires illumination under any condition

NEC Reference: NEC 110.26(D)

Question 16: NEC 110.26(D) prohibits working space illumination from being controlled by:

A manual wall switch alone
Automatic means only, with no manual override
Any lighting control method whatsoever
Daylight through a window

NEC Reference: NEC 110.26(D)

Question 17: NEC 110.26(D) does not require additional dedicated lighting for a working space when:

Adjacent or area lighting already illuminates the working space
The equipment is installed at night only
The equipment is rated under 15A
No exception to the illumination rule ever exists

NEC Reference: NEC 110.26(D)

Question 18: An inspector finds several storage boxes stacked directly in front of an electrical panel's required working space. What NEC rule does this violate?

NEC 110.26(B) — working space must be kept clear, not used for storage
No rule is violated — storage is always permitted in working space
NEC 680.26 — pool bonding requirements
NEC 250.122 — equipment grounding conductor sizing

NEC Reference: NEC 110.26(B)

Question 19: A 2000A switchboard, 8 ft wide, is installed with only a single entrance to its working space, and no unobstructed egress path or doubled clearance is provided. Does this comply with NEC 110.26(C)?

No — a second entrance is required since neither exception applies
Yes — one entrance is always sufficient regardless of equipment size
Yes — the two-entrance rule applies only to equipment over 5000A
It depends only on the color of the switchboard enclosure

NEC Reference: NEC 110.26(C)

Question 20: What is the underlying purpose of the two-entrance requirement in NEC 110.26(C)?

To provide a safe escape route during an arc-flash event or other emergency
To make the equipment room look more symmetrical
To reduce the equipment's purchase cost
There is no real safety purpose behind the rule

NEC Reference: NEC 110.26(C)

Question 21: How does working space depth in Table 110.26(A)(1) generally change as voltage increases from the lowest tier to the highest tier?

Depth requirements generally increase as voltage and condition severity increase
Depth requirements decrease as voltage increases
Depth requirements are identical at every voltage level
Voltage has no bearing on working space depth at all

NEC Reference: NEC Table 110.26(A)(1)

Question 22: NEC Article 110 is generally described as covering:

General requirements that apply across nearly every other article in the NEC
Rules that apply only to swimming pools
Rules that apply only to fire alarm systems
Rules with no application anywhere else in the NEC

NEC Reference: NEC Article 110

Question 23: Why does NEC 110.16 target equipment "likely to require examination, adjustment, servicing, or maintenance while energized" for arc flash labeling, rather than requiring the label on every piece of electrical equipment everywhere?

Because the label matters most where energized work is a realistic possibility
Because arc flash hazards only exist in equipment installed outdoors
Because every single receptacle in a building also needs this exact label
There is no reason for the scoping — it is arbitrary

NEC Reference: NEC 110.16

Question 24: Comparing the three voltage tiers of NEC Table 110.26(A)(1), which best describes the overall pattern?

Condition 1 stays at 3 ft across all tiers; Conditions 2 and 3 climb higher as voltage increases
All three conditions are identical at every voltage tier
Depth decreases as voltage increases across all three conditions
There are only two voltage tiers in the table, not three

NEC Reference: NEC Table 110.26(A)(1)

Question 25: Why is Article 110 often considered one of the most important articles for a master electrician to know cold, even though it does not cover any single piece of equipment specifically?

Its rules apply as a backdrop to nearly every installation, so mastering it avoids many of the most common violations
Article 110 is actually rarely tested or applied in practice
Article 110 applies only to swimming pool installations
Article 110 has been removed from the 2023 NEC

NEC Reference: NEC Article 110

Key NEC References for This Test

Article	What It Covers
Art. 220	Load Calculations — optional and standard methods for multifamily
Art. 230	Services — service design, sizing, multiple disconnects
Art. 430	Motors — complete branch circuit design (conductor + OCPD + overload + disconnect)
Art. 445	Generators — standby systems, transfer switches
Art. 450	Transformers — sizing, primary/secondary OCPD, installation
Art. 706	Energy Storage Systems — battery/solar storage (major NEC 2026 expansion)

Study Tip: Practice transformer kVA calculations daily. Know the formula: I = kVA × 1000 ÷ (V × 1.732) for three-phase. This comes up on almost every master exam.

Master Electrician Practice Test 29 – General Requirements & Working Space

How this test works

Frequently Asked Questions

Before You Start

Topics in This Test

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Key NEC References for This Test

Master Electrician Practice Test 29 – General Requirements & Working Space

How this test works

Frequently Asked Questions

Is this Master Electrician Practice Test 29 – General Requirements & Working Space free?

How do I qualify for the Master Electrician exam?

What is covered on the Master Electrician exam?

How is the Master exam different from the Journeyman exam?

Before You Start

Topics in This Test

Electrician Reviews

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Master Electrician Practice Test 29 – General Requirements & Working Space — Question List

Question 1: For equipment operating at 150V to ground or less, what working space depth does NEC Table 110.26(A)(1) require, across all three conditions?

Question 2: For equipment operating at 601 to 1000V, what working space depths does NEC Table 110.26(A)(1) require for Conditions 1, 2, and 3?

Question 3: NEC 110.26(A)(2) requires the width of a working space to be:

Question 4: NEC 110.16 requires an arc flash hazard warning label on which type of equipment?

Question 5: NEC 110.21(B) requires field-applied hazard markings to be:

Question 6: NEC 110.12 requires electrical installations to be:

Question 7: NEC 110.12(A) requires unused openings in an enclosure to be:

Question 8: NEC Table 110.28 provides enclosure type ratings so that an installer can:

Question 9: Per NEC Article 100, a "qualified person" is defined as someone who:

Question 10: NEC 110.26(F)(1)(a) extends the dedicated equipment space above a piece of electrical equipment up to:

Question 11: NEC 110.26(B) requires the working space around electrical equipment to be:

Question 12: NEC 110.26(C) requires large equipment rated 1200A or more and over 6 ft wide to have:

Question 13: Under NEC 110.26(C), each entrance to a large equipment working space must be at least:

Question 14: Under NEC 110.26(C), a single entrance is permitted for large equipment when:

Question 15: NEC 110.26(D) requires illumination for indoor working spaces around which type of equipment?

Question 16: NEC 110.26(D) prohibits working space illumination from being controlled by:

Question 17: NEC 110.26(D) does not require additional dedicated lighting for a working space when:

Question 18: An inspector finds several storage boxes stacked directly in front of an electrical panel's required working space. What NEC rule does this violate?

Question 19: A 2000A switchboard, 8 ft wide, is installed with only a single entrance to its working space, and no unobstructed egress path or doubled clearance is provided. Does this comply with NEC 110.26(C)?

Question 20: What is the underlying purpose of the two-entrance requirement in NEC 110.26(C)?

Question 21: How does working space depth in Table 110.26(A)(1) generally change as voltage increases from the lowest tier to the highest tier?

Question 22: NEC Article 110 is generally described as covering:

Question 23: Why does NEC 110.16 target equipment "likely to require examination, adjustment, servicing, or maintenance while energized" for arc flash labeling, rather than requiring the label on every piece of electrical equipment everywhere?

Question 24: Comparing the three voltage tiers of NEC Table 110.26(A)(1), which best describes the overall pattern?

Question 25: Why is Article 110 often considered one of the most important articles for a master electrician to know cold, even though it does not cover any single piece of equipment specifically?

Key NEC References for This Test

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