Mixed Deck — All Licensed Electrical Contractor Topics Flashcards
100 cards from real Licensed Electrical Contractor practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 20 Mixed Deck — All Licensed Electrical Contractor Topics flashcards as text
When calculating dryer load for a multifamily dwelling with 15 dryers, what demand factor applies per NEC Table 220.54?
Answer: 47%
For 15 dryers, NEC Table 220.54 specifies a demand factor of 47%.
A contractor who abandons a project without legal justification may face all of the following EXCEPT:
Answer: Mandatory criminal prosecution under federal law
Unjustified job abandonment is primarily a civil and licensing matter; it does not automatically trigger mandatory federal criminal prosecution, though fraud-related abandonment could involve criminal charges.
A 20A, 120V circuit is protected by a 20A AFCI breaker and also uses a GFCI outlet as the first device. A ground fault occurs downstream. Which device should operate first?
Answer: The GFCI outlet, as it is closest to the fault
The GFCI outlet closest to the fault should trip first due to its faster response to line-to-ground current imbalance at that point.
What is the minimum required height for overhead service conductors crossing a commercial parking lot subject to truck traffic?
Answer: 18 feet
NEC 225.18 requires overhead conductors to maintain at least 18 feet of clearance over areas subject to truck traffic.
What is the minimum rating required for any branch circuit that supplies two or more outlets or receptacles per NEC 210.3?
Answer: 15 amperes
NEC 210.3 establishes that branch circuit ratings shall not be less than the maximum load to be served, with 15 amperes being the minimum standard rating.
Per NEC 334.80, what is the maximum ambient temperature rating for standard Type NM cable?
Answer: 90°C
NEC 334.80 states that Type NM cable is rated at 90°C but the ampacity must be based on the 60°C column per the conductor temperature limitation.
In a 277/480V wye distribution system, which load is most appropriately connected line-to-neutral?
Answer: 277V fluorescent or LED lighting
277V is the phase-to-neutral voltage in a 480V wye system, making it ideal for fluorescent and LED lighting fixtures rated 277V.
In a parallel circuit, if one branch has a resistance of 10 Ω and another has 15 Ω, what is the total equivalent resistance?
Answer: 6 Ω
Parallel resistance: 1/Rt = 1/10 + 1/15 = 3/30 + 2/30 = 5/30, so Rt = 6 Ω.
Which type of insurance is mandatory in most states for an electrical contracting business as soon as it hires its first employee?
Answer: Workers' Compensation Insurance
Workers' compensation insurance is legally required in most states for businesses with employees. It covers medical expenses, lost wages, and rehabilitation costs for employees who are injured or become ill on the job. While other insurance types are essential, workers' compensation is the specific coverage directly tied to the act of employing staff.
Under NEC 110.16, arc-flash hazard warning labels are required on electrical equipment likely to require examination, adjustment, servicing, or maintenance while energized in which occupancy types?
Answer: Other than dwelling units
NEC 110.16 requires arc-flash warning labels on switchboards, panelboards, and similar equipment in other than dwelling units.
OSHA 29 CFR 1926.960 requires that when working on or near energized lines, rubber insulating gloves must be worn with leather protectors unless:
Answer: Leather protectors would prevent the work from being performed safely
Leather protectors may be omitted only when their use would prevent the work from being done safely, such as in extremely confined or awkward spaces.
A contractor receives a change order that increases the project scope. The contractor should:
Answer: Execute a written change order signed by both parties before starting the additional work
All scope changes should be documented with a signed written change order before work begins to protect both parties and ensure proper payment.
For a dwelling unit with 240-volt electric range rated at 12 kW, what is the maximum demand load permitted per NEC Table 220.55 Column C?
Answer: 8 kW
NEC Table 220.55 Column C permits an 8 kW maximum demand for a single household range rated up to 12 kW.
A subcontractor's bond that guarantees the subcontractor will complete the work per the contract is called a:
Answer: Performance bond
A performance bond guarantees that the bonded contractor will complete the project according to the contract terms, protecting the project owner if the contractor defaults.
What does Kirchhoff's Current Law (KCL) state?
Answer: The total current entering a node equals the total current leaving it
KCL states that the algebraic sum of all currents at any node (junction) in a circuit equals zero — current in equals current out.
When a metal water pipe is used as a grounding electrode, it must be supplemented by an additional electrode unless the pipe meets which condition?
Answer: No supplemental electrode is ever required with metal water pipes
NEC 250.53(D)(2) always requires a supplemental electrode when using a metal underground water pipe as a grounding electrode.
When should you replace a circuit breaker?
Answer: When they fail to reset or show damage.
Circuit breakers are designed to trip to protect circuits from overloads or short circuits. While occasional tripping is normal under fault conditions, a breaker that repeatedly trips, fails to reset, or shows visible signs of damage (like scorch marks or a burning smell) indicates a serious internal fault. In such cases, the breaker has likely failed internally and must be replaced to ensure continued circuit protection and safety.
Which NEC article governs the installation of emergency power systems in commercial buildings?
Answer: Article 700
NEC Article 700 covers emergency systems that are legally required and classified as essential for safety to human life.
NEC 410.130(G) requires luminaires installed in clothes closets to be what type?
Answer: LED or fluorescent enclosed types, surface-mounted or recessed
NEC 410.130(G) permits only enclosed LED or fluorescent luminaires surface-mounted or recessed in clothes closets to prevent fire hazards.
Service conductors supplying a one-family dwelling must have an ampacity of at least:
Answer: 100 amperes
NEC 230.79(C) requires a minimum 100-ampere service for one-family dwellings.