UT Electrician flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Purpose of NFPA 70

The National Electrical Code, NFPA 70, is an installation code of minimum requirements; it is not a design specification, manual, or instruction book for untrained persons.

Chapter 8 independence

Communications systems covered by NEC Chapter 8 are not subject to the requirements of Chapters 1 through 7 unless a Chapter 8 article specifically references them.

Chapters 5 through 7 role

Chapters 5, 6, and 7 supplement or modify Chapters 1 through 4 for special occupancies, special equipment, and special conditions; the general chapters still apply.

Three-phase power formula

In a balanced three-phase circuit, power in watts equals 1.732 times line-to-line voltage times line current times the power factor.

Continuous load conductor sizing

Branch-circuit conductors must have an ampacity of at least 125 percent of the continuous load plus 100 percent of the noncontinuous load before ampacity adjustment factors are applied.

Box fill for 12 AWG

For box-fill calculations, each 12 AWG conductor counts as 2.25 cubic inches, a 14 AWG counts 2.00, and a 10 AWG counts 2.50 cubic inches.

NM cable support interval

Nonmetallic-sheathed cable must be secured within 12 inches of every box or fitting and at intervals not exceeding 4.5 feet along its run.

Conduit fill three conductors

Where a raceway contains more than two conductors, the conductors may fill no more than 40 percent of the raceway cross-sectional area.

Direct burial depth general

General direct-buried conductors and cables require 24 inches of cover; residential branch circuits may be buried 12 inches and rigid metal conduit 6 inches.

Receptacle spacing wall rule

In dwelling units, receptacle outlets must be arranged so that no point along the floor line of any wall space is more than 6 feet from a receptacle.

Small conductor overcurrent limits

Under the small-conductor rule, 14 AWG copper is protected at 15 amperes, 12 AWG at 20 amperes, and 10 AWG at 30 amperes.

GFCI protection threshold

A Class A ground-fault circuit interrupter trips at 4 to 6 milliamperes; dwellings require GFCI protection in bathrooms, garages, outdoors, kitchens, laundry areas, and basements.

Ground rod supplemental electrode

A single ground rod that does not measure 25 ohms or less to earth must be supplemented by one additional electrode at least 6 feet away.

Concrete-encased electrode

A concrete-encased electrode consists of at least 20 feet of bare copper conductor or 1/2-inch reinforcing steel encased in concrete in direct contact with earth.

Equipment grounding conductor sizing

Equipment grounding conductors are sized using NEC Table 250.122 according to the ampere rating of the overcurrent device protecting the circuit, not the conductor size.

Luminaire closet clearance

A surface-mounted incandescent luminaire in a clothes closet needs 12 inches of clearance from the storage space; recessed and fluorescent types have smaller required clearances.

Fixed space heating load

Branch-circuit conductors and overcurrent devices for fixed electric space heating must be sized at not less than 125 percent of the total connected heating load.

Switch rating requirement

Snap switches must have current and voltage ratings not less than the load they control, and the switch must be marked with its ratings.

Motor inverse-time breaker

Short-circuit protection for a motor branch circuit using an inverse-time circuit breaker may be set as high as 250 percent of the motor full-load current.

Motor conductor ampacity

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the full-load current value taken from the appropriate NEC motor table.

Motor overload protection sizing

Overload protection for a motor marked with a service factor of 1.15 is generally sized at 125 percent of the nameplate full-load current.

Hazardous location classes

In the NEC hazardous location system, Class I locations contain flammable gases or vapors, Class II contains combustible dust, and Class III contains ignitable fibers or flyings.

Division 1 versus 2

Division 1 covers locations where the hazardous material is present under normal operating conditions; Division 2 covers abnormal conditions such as equipment failure or container rupture.

Emergency system definition

Emergency systems under Article 700 serve life safety and are legally mandated; optional standby systems under Article 702 have no such legal requirement.

Pool equipotential bonding

Pool shells, metal fittings, and associated equipment must be bonded together with a copper conductor not smaller than 8 AWG to form a common equipotential grid.

PV source current factor

Photovoltaic source circuit currents are multiplied by 125 percent before sizing conductors and overcurrent devices, because modules can exceed rated output.

Fire pump overcurrent protection

Fire pump overcurrent devices must be sized to carry the motor locked-rotor current indefinitely so the pump is not disconnected during starting.

Class 2 circuit definition

Class 2 circuits are power-limited circuits whose voltage and current are restricted by listed power supplies, allowing reduced wiring protection requirements.

Separation of Class 2

Class 2 and Class 3 conductors generally may not be placed in the same raceway, cable, or enclosure as electric light and power conductors.

Fire alarm circuit class

Class A fire alarm circuits continue to operate after a single open or ground fault; Class B circuits do not and signal the trouble condition instead.

Utah electrician licensing agency

The Utah Division of Occupational and Professional Licensing, within the Department of Commerce, licenses electricians and enforces the Electricians Licensing Act.

Utah electrical contractor license

In Utah, an electrical contractor license is required to bid or perform electrical work for compensation; contractor and electrician licenses are issued through DOPL.