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How many parts exist in Article 410?
17
When a capacitor that operates at 1,000 volts or less is removed from an energized circuit, the charge on the capacitor shall be drained to __ or less within __.
50V / 1 minute 460.6 (A)
Which of the following conditions must be met before two or more 120-volt, one-horsepower or less motors are permitted to be installed on the same 20-ampere branch circuit?
What is the full-load current of a 25-horsepower, 480-volt, 3-phase, squirrel-cage induction motor?
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A single-throw knife switch shall not be installed in a manner that will __.
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A panelboard is designed to be placed in a __.
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___ duty is defined as intermittent operation in which the load conditions are regularly recurrent.
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The maximum distance between two pieces of electrical equipment that are considered to be in sight of each other is __.
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A 100-ampere resistor bank is connected to a controller with conductor insulation rated 75°C. The resistors are not used in conjunction with the starting current of a motor.
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A cord-and-plug-connected kitchen waste disposer is installed below the kitchen sink, with the receptacle accessible. A four-foot length of Type SJ cord not subject to physical damage is used.
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A luminaire measuring 12 inches in diameter and weighing six pounds is supported by a screwshell of a lampholder.
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An embedded deicing unit of the resistance type shall not exceed __ of heated area.
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The ampacity of 18 AWG fixture wire is __.
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The voltage of a storage battery having 12 lead-acid type cells connected in series will be __.
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Type SJ flexible cord is recognized __.
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Each autotransformer 1,000 volts, nominal, or less shall be protected by an individual overcurrent device installed with each ungrounded input conductor and installed in series with the winding common to both the primary and secondary (shunt winding) of an autotransformer.
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In a residential occupancy, two fixed electric space-heating units are permitted to be supplied by a 30-ampere branch circuit.
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Under no condition is the attachment plug cap for a 240-volt room air conditioner in a residential occupancy permitted to be used as the disconnecting means for the room air conditioner.
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When pipelines are electrically heated, the pipelines must be identified by caution signs or markings.
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What type(s) of phase converters are covered by the NEC?
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Three-way switches are installed with the grounded conductor being switched in order to control a lighting fixture from two locations.
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A panelboard containing a 4-wire, delta-connected system shall be permanently field marked to identify the voltage to ground on the high leg.
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Insulated conductors used within a switchboard or switchgear shall be listed, flame retardant, and voltage rated.
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High-voltage is defined as a potential difference of more than __, nominal.
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An overhead projector is mounted below a suspended ceiling of a classroom. The power supply cord serving the projector is run through a hole in the suspended ceiling and is plugged into a receptacle outlet above the ceiling.
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Fixed, industrial-process heating equipment and motors shall be considered __.
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The means of emergency shutdown used for a generator's prime mover shall comply with which of the following provisions?
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Industrial control-panel enclosures shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices or other equipment, unless the conductors fill less than 50% of the cross-sectional area of the wiring space.
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Which of the following locations would not require a 15-ampere, 125-volt nonlocking-type receptacle to be listed tamper resistant?
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Low-voltage lighting systems shall not be supplied by a branch circuit rated greater than __.
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Study Notes
Article 410 Overview
- Article 410 contains 17 parts.
Capacitor Charge Discharge
- Capacitors operating at 1,000 volts or less must be drained to 50 volts or less within 1 minute after removal from an energized circuit.
Motor Branch Circuit Conditions
- Installation of two or more 120-volt, one-horsepower or less motors on the same 20-ampere branch circuit requires compliance with conditions listed in both sections A and B of 430.53.
Motor Current Ratings
- The full-load current for a 25-horsepower, 480-volt, 3-phase induction motor is 34 amps.
Knife Switch Installation
- A single-throw knife switch must not be installed in a manner that allows gravity to close the switch.
Panelboard Design
- Panelboards are designed for installation in cabinets.
Periodic Duty Definition
- Periodic duty refers to intermittent operation with regular recurrent load conditions.
Equipment Visibility Distance
- The maximum distance between two pieces of electrical equipment deemed "in sight" of each other is 50 feet.
Resistor Bank Violation
- Connecting a 100-ampere resistor bank with 75°C conductor insulation violates NEC guidelines for use unrelated to motor starting current.
Kitchen Waste Disposer Violation
- A cord-and-plug-connected kitchen waste disposer installed beneath a kitchen sink using a four-foot length of Type SJ cord that is not subject to physical damage is in violation.
Luminaire Support Standards
- A luminaire that is 12 inches in diameter and weighs six pounds can be supported by the screwshell of a lampholder.
Deicing Unit Limit
- An embedded resistance deicing unit's wattage must not exceed 120 watts per square foot of heated area.
Fixture Wire Ampacity
- The ampacity of 18 AWG fixture wire is 6 amps.
Storage Battery Voltage
- A storage battery containing 12 lead-acid cells in series has a voltage of 24 volts.
Type SJ Flexible Cord
- Type SJ flexible cord is classified as a hard usage cord.
Autotransformer Protection Requirement
- Autotransformers rated 1,000 volts nominal or less do not require individual overcurrent protection for each ungrounded input conductor.
Heating Units in Residences
- Two fixed electric space-heating units in residential occupancy can be supplied by a single 30-ampere branch circuit.
Air Conditioner Disconnect Requirement
- The attachment plug for a 240-volt room air conditioner cannot be used as the disconnecting means.
Caution for Electrically Heated Pipelines
- Pipelines that are electrically heated must display caution signs or markings.
Phase Converters in NEC
- The NEC covers both types B and C of phase converters.
Three-Way Switch Violations
- Installing three-way switches to switch the grounded conductor to control a fixture from multiple locations is a violation.
Panelboard Voltage Marking
- Panelboards with a 4-wire, delta-connected system must be marked to indicate the voltage to ground on the high leg.
Insulated Conductors Requirements
- Insulated conductors within switchboards or switchgear must be listed, flame-retardant, and rated for voltage.
High Voltage Definition
- High voltage is defined as a nominal potential difference greater than 1,000 volts.
Overhead Projector Installation Violation
- Mounting an overhead projector below a suspended ceiling and running its power supply cord through a hole above the ceiling violates NEC rules.
Industrial Heating Loads
- Fixed industrial-process heating equipment and motors are classified as continuous loads.
Generator Shutdown Compliance
- Emergency shutdown means for a generator's prime mover must comply with specified provisions.
Industrial Control-Panel Enclosures
- Control-panel enclosures should not act as junction boxes or raceways unless filling less than 50% of wiring space.
Tamper-Resistant Receptacles
- A conference room in a business office does not require a tamper-resistant 15-ampere, 125-volt nonlocking-type receptacle.
Low-Voltage Lighting Circuit Limits
- Low-voltage lighting systems must not be supplied by a branch circuit rated higher than 20 amps.
Studying That Suits You
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Description
Test your knowledge on the key concepts from NEC Chapter 4 with these flashcards. This quiz will challenge your understanding of the electrical code, capacitor requirements, and conditions for motor installations. Perfect for students or professionals looking to refresh their knowledge.
