CA C10 Electrical Contractor Exam

CA C10 Electrical Contractor Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

• What is the maximum allowable voltage drop for branch circuits in a

residential dwelling?

• 1%
• 3%
• 5%

D. 10%

Rationale: The NEC recommends a maximum voltage drop of 5% for

branch circuits to ensure efficient operation of electrical equipment and minimize energy loss.

• Which type of conduit is typically used for outdoor installations

exposed to moisture?

A. EMT

B. PVC

C. IMC

D. RMC

Rationale: PVC conduit is non-metallic, corrosion-resistant, and

suitable for wet locations.

• A 20-ampere circuit breaker is installed in a branch circuit. What is the

maximum size copper wire allowed?

A. 12 AWG

B. 12 AWG

C. 10 AWG

D. 14 AWG

Rationale: NEC allows 12 AWG copper wire for a 20-ampere circuit;

using larger wire is allowed but not necessary.

• What is the primary function of a GFCI outlet?
• Protect equipment 1 / 3

• Protect people from electric shock
• Reduce voltage drop
• Increase current flow

Rationale: Ground Fault Circuit Interrupters detect differences in

current and quickly disconnect power to prevent electrical shock.

• Which type of wiring method is permitted in damp locations?
• NM cable
• AC cable (Armored Cable)
• UF cable
• SE cable

Rationale: Armored cable (AC) is approved for use in damp

locations; NM cable is not rated for wet or damp areas.

• What is the minimum clearance for service panels in front of electrical

equipment?

• 24 inches
• 28 inches
• 36 inches
• 48 inches

Rationale: NEC requires 36 inches of clear working space in front of

service panels for safety and accessibility.

• What is the NEC color code for a grounded conductor in residential

wiring?

• White or gray
• Black
• Red
• Green

Rationale: Grounded conductors (neutrals) are white or gray

according to NEC color codes.

• Which device protects circuits from short circuits and overloads?
• Fuse
• Circuit breaker
• Transformer
• Receptacle

Rationale: Circuit breakers automatically disconnect power during

overcurrent or short circuit conditions.

• What is the purpose of bonding in electrical systems?
• Reduce power usage 2 / 3

• Provide a low-resistance path to ground
• Increase voltage
• Protect from voltage drop

Rationale: Bonding ensures that all metal parts are electrically

connected, preventing potential shock hazards.

• When installing electrical boxes in a wall, what is the minimum

box depth for standard residential outlets?

• 1-1/2 inches
• 2 inches
• 2-1/2 inches
• 3 inches

Rationale: Standard electrical boxes must accommodate wire

connections and devices; NEC requires at least 2-1/2 inches depth for outlets.

• What is the typical voltage for a single-phase residential service?
• 120V only
• 240V only

C. 120/240V

D. 208V

Rationale: Residential services typically use 120/240V single-phase

systems for standard appliances and lighting.

• Which NEC article governs grounding and bonding?
• Article 210
• Article 220
• Article 250
• Article 300

Rationale: NEC Article 250 covers grounding, bonding, and related

requirements.

• What is the maximum ampacity of 14 AWG copper wire in a

residential branch circuit?

A. 10A

B. 15A

C. 20A

D. 25A

Rationale: NEC allows 14 AWG copper wire to carry up to 15

amperes for branch circuits.

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