Mixed Deck — All NEC Topics Flashcards

Is the NEC itself a law, or does it become enforceable through adoption?

Answer: It becomes enforceable only when adopted by a state or local jurisdiction

The NEC is a model code that gains legal force only when adopted by a governmental jurisdiction.

Conductors with _____ marked on the insulation are not allowed to be used in wet locations.

Answer: THHN

As shown in Table 310.104(A), conductors with THHN insulation are approved for use in dry and damp locations only and conductors with THWN, THHW, and THW insulation are recognized for use in dry and wet locations.

What is the maximum overcurrent protection allowed on a 14 AWG copper branch circuit conductor?

Answer: 15 amperes

Per NEC 240.4(D), 14 AWG copper is limited to 15-ampere overcurrent protection.

Which of the following machines is the most efficient?

Answer: Electrical Transformer

Electrical Transformer will have higher efficiency as there is no rotating parts and airgap in the flux path involved in it. Generally efficiency of the Transformer is of the order of 95% to 99% during full load operation

Per NEC 110.16, what label must be field-applied to certain equipment to warn of arc-flash hazards?

Answer: Arc flash and shock hazard warning

NEC 110.16 requires arc-flash hazard warning labels on equipment likely to be examined while energized.

Under NEC Article 100, what is the definition of 'ampacity'?

Answer: The current in amperes a conductor can carry continuously under conditions of use without exceeding its temperature rating

Ampacity is defined in Article 100 as the current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating.

A dwelling-unit bathroom requires at least one branch circuit of what rating for its receptacle outlets?

Answer: 20 amperes

NEC 210.11(C)(3) requires a 20-amp branch circuit for bathroom receptacles.

Which NEC article covers wiring methods?

Answer: Article 300

Article 300 of the NEC provides the general requirements for wiring methods and materials used in electrical installations. It covers fundamental principles such as conductor protection, mechanical continuity, and the proper installation of various wiring systems. This article serves as a foundational reference for ensuring safe and compliant wiring practices across different applications.

Wherever flexible cords with attachment plugs are to be used, a receptacle outlet needs to be constructed, and receptacles are __________ for the same type of cords there where they can be permanently linked.

Answer: permitted to be omitted

NEC Article 210.50(A) generally requires receptacle outlets where flexible cords with attachment plugs are used. However, it also states that receptacles are permitted to be omitted for the same type of cords where they can be permanently connected. This exception applies when equipment is hard-wired or permanently connected, eliminating the need for a receptacle outlet for that specific piece of equipment.

What is the maximum number of disconnecting means permitted for a service under the NEC 'six disconnect' rule prior to recent grouping changes?

Answer: 6

NEC 230.71 historically permitted up to six service disconnecting means grouped together.

GFCI protection is required for 125-volt, 15- and 20-ampere receptacles installed in which dwelling location?

Answer: Garages

NEC 210.8(A) requires GFCI protection for receptacles in garages.

Tamper-resistant receptacles are required in dwelling units to:

Answer: Prevent children from inserting objects

Tamper-resistant receptacles have shutters that prevent children from inserting foreign objects.

When calculating the service load for a dwelling with two 240V/30A small appliance circuits and one laundry circuit, what total load in VA is assigned to these circuits before demand factors?

Answer: 4,500 VA

Three circuits × 1,500 VA each = 4,500 VA; NEC 220.52 requires a minimum of 1,500 VA per small appliance and laundry circuit.

Under NEC 250.24(A), a service-entrance grounded conductor (neutral) must be connected to the grounding electrode system at which location?

Answer: At the service disconnecting means enclosure

NEC 250.24(A) requires the grounded conductor to be bonded to the grounding electrode system at the service disconnecting means.

Per NEC 240.4(F), what protects secondary conductors of a single-phase 2-wire transformer?

Answer: Primary overcurrent protection sized per the secondary-to-primary voltage ratio

NEC 240.4(F) allows primary protection to protect 2-wire secondary conductors when sized accounting for the voltage ratio.

How does the NEC define a 'branch circuit'?

Answer: The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s)

A branch circuit consists of the circuit conductors between the final overcurrent protective device and the outlet(s) it serves.

For use in PV source circuits within the PV array, single-conductor cable such as _____ and single-conductor cable listed and labeled as solar photovoltaic (PV) wire are permitted.

Answer: USE-2

NEC 690.31(C) permits the use of specific single-conductor cables, such as Type USE-2, Type RHW-2, Type XHHW-2, and single-conductor cable listed and labeled as solar photovoltaic (PV) wire, for PV source circuits within the PV array. These cable types are designed to withstand the harsh outdoor conditions, including UV exposure, moisture, and temperature extremes, ensuring the durability and safety required for photovoltaic installations.

A dwelling has 10 kVA of fastened-in-place appliances (six units). What demand load is used?

Answer: 7.5 kVA

With four or more appliances, the 75% factor applies: 10 kVA x 0.75 = 7.5 kVA.

Per NEC 240.4(D), what is the maximum overcurrent protection for a 12 AWG copper conductor?

Answer: 20 amperes

NEC 240.4(D) limits 12 AWG copper to a maximum overcurrent device of 20 amperes.

A 1.5-ton residential A/C draws 24 A at 240 V. What VA is this for the optional calc?

Answer: 5760 VA

240 V x 24 A = 5760 VA.