Mixed Deck — All Electrician Topics Flashcards

What is the NEC requirement for the minimum working space depth in front of a 120/240V residential panel?

Answer: 30 inches

NEC 110.26(A)(1) requires a minimum working space of 3 feet (36 inches) in front of electrical equipment up to 150V to ground.

Per the NEC, what is the minimum headroom clearance required in front of electrical panels?

Answer: 6 feet

NEC 110.26 requires a minimum of 6 feet 6 inches headroom, but 6 feet is the minimum working clearance at the panel face.

What is the reactance of a capacitor called?

Answer: Capacitive reactance

The opposition a capacitor provides to AC current is called capacitive reactance (Xc), measured in ohms.

Which NEC article covers swimming pools, fountains, and similar installations?

Answer: Article 680

NEC Article 680 covers the special electrical requirements for swimming pools, hot tubs, spas, and fountains.

Which conductor insulation type is rated for use in wet locations and direct burial?

Answer: XHHW-2

XHHW-2 insulation is rated for use in wet locations and is suitable for direct burial applications.

What is the nameplate 'service factor' of a motor?

Answer: The multiplier indicating how much above nameplate load the motor can handle continuously

The service factor is a multiplier that indicates how much above the rated load a motor can operate continuously without damage.

What happens when a circuit breaker trips?

Answer: It automatically opens the circuit to interrupt overcurrent

A circuit breaker automatically opens to interrupt current flow when it detects an overload or short circuit condition.

Per the NEC, what is the maximum length a flexible cord can be used as a substitute for fixed wiring?

Answer: Flexible cords are never permitted as fixed wiring

The NEC prohibits using flexible cords as a substitute for fixed building wiring under NEC 400.12.

What does a contactor do in a motor control circuit?

Answer: Electrically switches the motor power circuit on and off

A contactor is an electrically operated switch (controlled by a low-voltage coil) used to switch the high-power motor circuit on and off.

What type of wiring method is commonly referred to as 'Romex'?

Answer: Nonmetallic-sheathed cable (NM)

Romex is the brand name commonly used for nonmetallic-sheathed cable (NM cable) per NEC Article 334.

What is the total power consumed by a 120V circuit with 10 amps at a power factor of 0.8?

Answer: 960 watts

True power P = V × I × PF = 120 × 10 × 0.8 = 960 watts.

What is the primary purpose of using liquid-tight flexible metal conduit (LFMC)?

Answer: To allow movement and vibration while maintaining a watertight seal

LFMC is used where flexibility is needed and moisture protection is required, such as connections to HVAC equipment.

What is the difference between a service lateral and a service drop?

Answer: A lateral is underground; a drop is overhead

A service lateral refers to underground service conductors, while a service drop refers to overhead conductors from the utility.

Which NEC table is used to determine the minimum size of a grounding electrode conductor based on the size of the service entrance conductors?

Answer: Table 250.66

NEC Table 250.66 cross-references service entrance conductor size to the minimum required grounding electrode conductor size.

What type of connector must be used when terminating EMT at an enclosure in a wet location?

Answer: Raintight compression connector

In wet locations, raintight compression connectors are required to maintain the integrity of the watertight seal at enclosure entries.

Per the NEC, overload protection for a motor must trip at what maximum percentage of the motor's full-load current for motors with a 1.15 service factor?

Answer: 125%

NEC 430.32 requires overload devices to trip at no more than 125% of the motor's nameplate full-load current for motors with a 1.15 service factor.

What does NEMA stand for in the context of motor control enclosures?

Answer: National Electrical Manufacturers Association

NEMA stands for National Electrical Manufacturers Association, which sets standards for motor control enclosure ratings.

What is the maximum number of 90-degree bends allowed in a single conduit run between pull points?

Answer: 4

The NEC limits conduit runs to a maximum of 360 degrees of total bends (equivalent to four 90-degree bends) between pull points.

Per NEC 250.52(A)(1), a metal underground water pipe used as a grounding electrode must have at least how many feet of direct earth contact?

Answer: 10 feet

NEC 250.52(A)(1) requires a metal underground water pipe to be in direct contact with the earth for at least 10 feet to qualify as a grounding electrode.

According to the NEC, motor branch circuit conductors must be sized at what minimum percentage of the motor's full-load current (FLC)?

Answer: 125%

NEC 430.22 requires motor branch circuit conductors to be sized at no less than 125% of the motor's full-load current.