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MASTER NEC 2023

Master Electrician Practice Test 30 – GFCI/AFCI Requirements & Feeders Deep Dive

This is Master Electrician Practice Test 30 — GFCI/AFCI Requirements & Feeders Deep Dive, the final test in this practice series. It covers the full dwelling-unit GFCI location list, the AFCI-protected room list, multiwire branch circuit disconnect rules, and feeder sizing under Article 215. The test has 25 multiple-choice questions on where GFCI and AFCI protection is required, how multiwire branch circuits must be disconnected, and how to size a feeder for combined continuous and noncontinuous loads. 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

GFCI/AFCI & Feeders

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

GFCI required in bathrooms — every receptacle, no exceptions (NEC 210.8(A)(1))
GFCI required in kitchens — all 125-250V receptacles, not just countertop ones (NEC 210.8(A)(6))
GFCI required in garages and accessory buildings at or below grade (NEC 210.8(A)(2))
GFCI required outdoors (NEC 210.8(A)(3))
GFCI required in crawl spaces at or below grade (NEC 210.8(A)(4))
GFCI required in unfinished basements (NEC 210.8(A)(5))
GFCI required within 6 ft of any sink, in any room (NEC 210.8(A)(7))
GFCI required for dwelling-unit dishwasher branch circuits (NEC 210.8(A)(9))
GFCI required within 6 ft of a bathtub or shower stall (NEC 210.8(A)(10))
GFCI required in laundry areas (NEC 210.8(A)(11))
The dwelling-unit GFCI list grew to 12 locations in recent NEC cycles (NEC 210.8(A))
AFCI-protected room list — kitchens, family rooms, bedrooms, and more (NEC 210.12(B))
Which branch circuits AFCI protection applies to (NEC 210.12(B))
AFCI devices must be readily accessible (NEC 210.12)
AFCI protection on branch circuit extensions and modifications (NEC 210.12(D))
Multiwire branch circuits need a simultaneous disconnecting means (NEC 210.4(B))
Why an open neutral on a multiwire circuit is dangerous
Handle ties and two-pole common-trip breakers as compliant methods (NEC 210.4(B))
Feeder ampacity — 125% of continuous load plus 100% of noncontinuous load (NEC 215.2(A)(1))
The 100%-rated assembly exception to the 125% feeder rule (NEC 215.2)
Worked feeder-sizing calculation combining continuous and noncontinuous loads
Voltage drop guidance — 3%/5% recommendation, not a hard requirement (Informational Notes to 210.19 and 215.2)
Scenario — an ungrounded kitchen receptacle with no GFCI protection
Scenario — a multiwire circuit fed by two single-pole breakers with no handle tie
Comparing GFCI's per-location approach to AFCI's per-room approach

Tip: GFCI protects people from shock by watching for current leaking to ground; AFCI protects property from fire by watching for the electrical signature of arcing. Keep that distinction in mind and the two location lists start to make a lot more sense.

Questions

45 min

Time

70%

Pass

Timer starts immediately. Progress is auto-saved.

Master Electrician Practice Test 30 – GFCI/AFCI Requirements & Feeders Deep Dive — Question List

Question 1: In a dwelling unit, which receptacles in a bathroom require GFCI protection?

Every receptacle in the bathroom
Only receptacles within 3 ft of the sink
Only receptacles rated 30A or higher
None — bathrooms are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(1)

Question 2: In a dwelling-unit kitchen, which receptacles need GFCI protection under NEC 210.8(A)(6)?

All 125V-250V receptacles in the kitchen, not only countertop ones
Only receptacles serving the countertop
Only 125V receptacles under 20A
None — kitchens are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(6)

Question 3: NEC 210.8(A)(2) requires GFCI protection for receptacles in garages and accessory buildings when they are:

At or below grade level, in areas not intended as habitable rooms
Above the second floor only
Only in garages with a car lift installed
Garages are exempt from GFCI protection entirely

NEC Reference: NEC 210.8(A)(2)

Question 4: NEC 210.8(A)(3) requires GFCI protection for which dwelling-unit receptacles?

Outdoor receptacles
Only receptacles under a covered porch
Only receptacles more than 20 ft from the house
Outdoor receptacles are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(3)

Question 5: NEC 210.8(A)(4) requires GFCI protection in dwelling-unit crawl spaces when they are:

At or below grade level
Only if the crawl space is heated
Only if the crawl space exceeds 500 sq ft
Crawl spaces are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(4)

Question 6: NEC 210.8(A)(5) requires GFCI protection in which part of a dwelling-unit basement?

Unfinished portions not intended as habitable rooms
Only fully finished basements with carpet
Only basements with an exterior walkout door
Basements are exempt from GFCI protection entirely

NEC Reference: NEC 210.8(A)(5)

Question 7: NEC 210.8(A)(7) requires GFCI protection for any receptacle within what distance of a sink, regardless of which room the sink is in?

6 ft from the outside edge of the sink
3 ft from the outside edge of the sink
10 ft from the outside edge of the sink
This rule applies only to kitchen sinks

NEC Reference: NEC 210.8(A)(7)

Question 8: NEC 210.8(A)(9) requires GFCI protection for a dwelling-unit dishwasher's branch circuit:

Whether it is cord-and-plug connected or hard-wired
Only if it is cord-and-plug connected
Only if it is hard-wired directly
Dishwashers are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(9)

Question 9: NEC 210.8(A)(11) requires GFCI protection for receptacles in which dwelling-unit location?

Laundry areas
Formal dining rooms
Home offices
Laundry areas are exempt from GFCI protection

NEC Reference: NEC 210.8(A)(11)

Question 10: How many distinct dwelling-unit locations does the NEC 210.8(A) GFCI list now cover?

12 locations
4 locations
6 locations
20 locations

NEC Reference: NEC 210.8(A)

Question 11: NEC 210.12(B) requires AFCI protection in which of these dwelling-unit rooms?

Bedrooms, family rooms, kitchens, living rooms, and similar finished spaces
Only detached garages
Only unfinished basements
No rooms — AFCI applies only to commercial buildings

NEC Reference: NEC 210.12(B)

Question 12: NEC 210.12(B) applies AFCI protection to which type of branch circuits?

120V, single-phase, 10A, 15A, and 20A branch circuits
240V, single-phase circuits only
Only three-phase circuits
Only circuits rated 30A or higher

NEC Reference: NEC 210.12(B)

Question 13: NEC 210.12 requires an AFCI device to be installed in a location that is:

Readily accessible
Permanently sealed behind drywall
Located only in an attic
There is no accessibility requirement

NEC Reference: NEC 210.12

Question 14: Under NEC 210.12(D), when an existing dwelling-unit branch circuit is extended or modified in an area covered by 210.12(B), what does the code generally require?

AFCI protection generally must be added to the extended or modified circuit
The rest of the house must also be retrofitted with AFCI protection
AFCI protection is never required on existing circuits under any condition
The circuit must be abandoned rather than extended

NEC Reference: NEC 210.12(D)

Question 15: NEC 210.4(B) requires a multiwire branch circuit to have a disconnecting means that:

Simultaneously disconnects all ungrounded conductors at the origin
Disconnects only the neutral conductor
Disconnects one ungrounded conductor at a time, on separate switches
Is not required at all for multiwire branch circuits

NEC Reference: NEC 210.4(B)

Question 16: Why is the simultaneous-disconnect rule in NEC 210.4(B) so important for multiwire branch circuits?

A shared neutral can stay energized from the other leg if only one hot is disconnected
It has nothing to do with safety, only with equipment cost
It only matters for circuits over 277V
Multiwire circuits never actually share a neutral conductor

NEC Reference: NEC 210.4(B)

Question 17: Which of these methods satisfies the NEC 210.4(B) simultaneous-disconnect requirement for a multiwire branch circuit fed by two single-pole breakers?

An approved handle tie identified for the purpose, linking both breaker handles
Leaving the two breakers completely independent with no tie
Labeling the panel only, with no physical linking device
There is no method that satisfies this rule with single-pole breakers

NEC Reference: NEC 210.4(B)

Question 18: Per NEC 215.2(A)(1), the minimum ampacity of a feeder supplying both continuous and noncontinuous loads must be at least:

125% of the continuous load plus 100% of the noncontinuous load
100% of the continuous load plus 125% of the noncontinuous load
100% of the combined total load, with no multiplier
150% of the continuous load only, ignoring noncontinuous load

NEC Reference: NEC 215.2(A)(1)

Question 19: When does NEC 215.2 permit a feeder to be sized at just 100% of the combined continuous and noncontinuous load, instead of applying the usual 125% factor?

When the assembly, including its overcurrent protection, is listed for 100% operation
Whenever the installer prefers smaller conductors
Only in single-family dwellings
This exception does not exist in the NEC

NEC Reference: NEC 215.2

Question 20: A feeder supplies a 32A continuous load and an 18A noncontinuous load, using standard (not 100%-rated) equipment. What minimum ampacity must the feeder have?

58A
50A
40A
62.5A

NEC Reference: NEC 215.2(A)(1)

Question 21: What does the NEC say about the commonly cited 3% branch-circuit / 5% total system voltage drop figures?

They are recommendations in Informational Notes, not enforceable requirements
They are hard mandatory limits enforced on every installation
They apply only to swimming pool circuits
The NEC has never mentioned any voltage drop percentage

NEC Reference: NEC Informational Notes to 210.19 and 215.2

Question 22: An inspector finds a kitchen receptacle 4 ft from the sink, on a 125V circuit, with no GFCI protection. Does this comply with the NEC?

No — it is within 6 ft of the sink and in a kitchen, so GFCI protection is required
Yes — GFCI is only required within 3 ft of a kitchen sink
Yes — kitchens are fully exempt from GFCI protection
It depends only on the receptacle's amperage rating

NEC Reference: NEC 210.8(A)(6)-(7)

Question 23: A multiwire branch circuit originates from two single-pole breakers in a panel, with no handle tie and no common-trip mechanism between them. Does this comply with NEC 210.4(B)?

No — a handle tie or common-trip mechanism is required for simultaneous disconnect
Yes — two independent single-pole breakers always satisfy 210.4(B)
Yes — the rule only applies to circuits over 240V
It depends only on the panel manufacturer

NEC Reference: NEC 210.4(B)

Question 24: How do the GFCI list (210.8(A)) and the AFCI list (210.12(B)) generally differ in the way they identify covered locations?

GFCI targets damp/wet shock-risk spots; AFCI targets whole finished living-space rooms
The two lists are actually identical, room for room
GFCI applies only to commercial buildings and AFCI only to dwellings
Neither list has anything to do with location at all

NEC Reference: NEC 210.8(A), 210.12(B)

Question 25: Fundamentally, what is the core difference between what GFCI protection and AFCI protection are each designed to prevent?

GFCI prevents shock from ground-fault current; AFCI prevents fire from arcing faults
GFCI and AFCI are two names for the exact same protection function
GFCI prevents fire; AFCI prevents shock — the reverse of their actual functions
Neither device is designed to prevent any specific hazard

NEC Reference: NEC Article 100 (Definitions)

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 30 – GFCI/AFCI Requirements & Feeders Deep Dive

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Topics in This Test

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Key NEC References for This Test

Master Electrician Practice Test 30 – GFCI/AFCI Requirements & Feeders Deep Dive

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Master Electrician Practice Test 30 – GFCI/AFCI Requirements & Feeders Deep Dive — Question List

Question 1: In a dwelling unit, which receptacles in a bathroom require GFCI protection?

Question 2: In a dwelling-unit kitchen, which receptacles need GFCI protection under NEC 210.8(A)(6)?

Question 3: NEC 210.8(A)(2) requires GFCI protection for receptacles in garages and accessory buildings when they are:

Question 4: NEC 210.8(A)(3) requires GFCI protection for which dwelling-unit receptacles?

Question 5: NEC 210.8(A)(4) requires GFCI protection in dwelling-unit crawl spaces when they are:

Question 6: NEC 210.8(A)(5) requires GFCI protection in which part of a dwelling-unit basement?

Question 7: NEC 210.8(A)(7) requires GFCI protection for any receptacle within what distance of a sink, regardless of which room the sink is in?

Question 8: NEC 210.8(A)(9) requires GFCI protection for a dwelling-unit dishwasher's branch circuit:

Question 9: NEC 210.8(A)(11) requires GFCI protection for receptacles in which dwelling-unit location?

Question 10: How many distinct dwelling-unit locations does the NEC 210.8(A) GFCI list now cover?

Question 11: NEC 210.12(B) requires AFCI protection in which of these dwelling-unit rooms?

Question 12: NEC 210.12(B) applies AFCI protection to which type of branch circuits?

Question 13: NEC 210.12 requires an AFCI device to be installed in a location that is:

Question 14: Under NEC 210.12(D), when an existing dwelling-unit branch circuit is extended or modified in an area covered by 210.12(B), what does the code generally require?

Question 15: NEC 210.4(B) requires a multiwire branch circuit to have a disconnecting means that:

Question 16: Why is the simultaneous-disconnect rule in NEC 210.4(B) so important for multiwire branch circuits?

Question 17: Which of these methods satisfies the NEC 210.4(B) simultaneous-disconnect requirement for a multiwire branch circuit fed by two single-pole breakers?

Question 18: Per NEC 215.2(A)(1), the minimum ampacity of a feeder supplying both continuous and noncontinuous loads must be at least:

Question 19: When does NEC 215.2 permit a feeder to be sized at just 100% of the combined continuous and noncontinuous load, instead of applying the usual 125% factor?

Question 20: A feeder supplies a 32A continuous load and an 18A noncontinuous load, using standard (not 100%-rated) equipment. What minimum ampacity must the feeder have?

Question 21: What does the NEC say about the commonly cited 3% branch-circuit / 5% total system voltage drop figures?

Question 22: An inspector finds a kitchen receptacle 4 ft from the sink, on a 125V circuit, with no GFCI protection. Does this comply with the NEC?

Question 23: A multiwire branch circuit originates from two single-pole breakers in a panel, with no handle tie and no common-trip mechanism between them. Does this comply with NEC 210.4(B)?

Question 24: How do the GFCI list (210.8(A)) and the AFCI list (210.12(B)) generally differ in the way they identify covered locations?

Question 25: Fundamentally, what is the core difference between what GFCI protection and AFCI protection are each designed to prevent?

Key NEC References for This Test

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