OK Electrician flashcards

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

Working space depth, 480 volts

For equipment operating at 151 to 600 volts to ground, NEC Table 110.26(A)(1) requires a working space depth of 3 ft for Condition 1, 3.5 ft for Condition 2, and 4 ft for Condition 3.

Meaning of listed equipment

Equipment is listed when it appears in a list published by an organization acceptable to the authority having jurisdiction that evaluates products and maintains periodic inspection of production of listed equipment.

Dedicated equipment space dimensions

NEC 110.26(E) requires a dedicated equipment space extending 30 in. from the front of electrical equipment, the width of the equipment, and 6 ft above it or to the structural ceiling.

Available fault current marking

NEC 110.24 requires service equipment in other than dwelling units to be field marked with the maximum available fault current and the date the fault current calculation was performed.

NM cable fastening intervals

Nonmetallic-sheathed cable must be secured within 12 in. of each box and at intervals not exceeding 4.5 ft, as required by NEC 334.30.

Box volume per 12 AWG

NEC Table 314.16(B) assigns 2.25 cubic inches of box volume per 12 AWG conductor, 2.0 for 14 AWG, 2.5 for 10 AWG, and 1.75 for 18 and 16 AWG.

Direct burial cover, UF cable

NEC Table 300.5 requires 24 in. of cover for direct-buried UF cable generally, reduced to 18 in. for 120 V, 20 A residential circuits and 12 in. where GFCI-protected.

Angle pull box sizing

NEC 314.28(A)(2) requires an angle-pull box dimension of at least six times the trade size of the largest raceway, plus the trade sizes of the other raceways in the same row.

Small conductor protection, 14 AWG

NEC 240.4(D) limits overcurrent protection for 14 AWG copper to 15 A, for 12 AWG to 20 A, and for 10 AWG to 30 A, apart from specific permitted exceptions.

Concrete-encased grounding electrode

A concrete-encased electrode is at least 20 ft of 1/2 in. or larger reinforcing steel, or 4 AWG bare copper, encased in at least 2 in. of concrete near the bottom of a footing.

Equipment grounding conductor, 200 A

NEC Table 250.122 requires a 6 AWG copper equipment grounding conductor for a circuit protected by a 200 A overcurrent device, while a 100 A device requires 8 AWG copper.

Ten-foot tap rule

NEC 240.21(B)(1) permits a tap up to 10 ft long if its ampacity is at least one-tenth the rating of the overcurrent device ahead of it, with no splices and a single termination.

Dwelling receptacle wall spacing

NEC 210.52(A)(1) requires dwelling receptacle outlets so that no point along the wall line is more than 6 ft from a receptacle, which limits outlets to 12 ft apart.

Two small appliance circuits

NEC 210.11(C)(1) requires at least two 20 A small-appliance branch circuits for dwelling kitchen, pantry and dining areas, supplying only receptacle outlets there.

Overhead service clearance, driveway

NEC 230.24 requires overhead service conductors to have at least 12 ft clearance above a residential driveway, 10 ft above a sidewalk, and 18 ft above a public road.

Dwelling service disconnect rating

NEC 230.79(C) requires the service disconnecting means for a one-family dwelling to have a rating of not less than 100 A, with a three-wire service.

Flexible cord prohibited uses

NEC 400.8 prohibits using flexible cord as a substitute for fixed wiring, running it through holes in walls or ceilings, or concealing it above suspended ceilings.

Water heater branch circuit

NEC 422.13 requires the branch circuit for a storage-type water heater rated 20 gallons or more to have an ampacity of at least 125 percent of the appliance nameplate rating.

Air-conditioning disconnect location

NEC 440.14 requires the disconnecting means for air-conditioning and refrigerating equipment to be located within sight of and not more than 50 ft from the equipment.

Hazardous location classes

NEC Article 500 designates Class I for flammable gases and vapors, Class II for combustible dust, and Class III for ignitable fibers or flyings, each divided into Division 1 and Division 2.

Pool perimeter equipotential bonding

NEC 680.26 requires equipotential bonding of conductive pool shell parts and of perimeter surfaces extending at least 3 ft horizontally from the inside walls of the pool.

Photovoltaic source circuit current

NEC 690.8(A) requires photovoltaic source-circuit current to be calculated at 125 percent of short-circuit current, and conductor ampacity to be at least 125 percent of that result.

PV rapid shutdown voltage

NEC 690.12 requires rapid shutdown to reduce conductors outside the photovoltaic array boundary to 30 volts or less within 30 seconds after shutdown is initiated.

Motor full-load current source

NEC 430.6(A)(1) requires motor full-load current for sizing conductors, feeders and protection to be taken from Tables 430.247 through 430.250, not from the motor nameplate.

Motor branch circuit 125 percent

NEC 430.22 requires branch-circuit conductors supplying a single motor to have an ampacity of at least 125 percent of the motor full-load current rating.

Motor overload, 1.15 service factor

NEC 430.32 requires overload protection set at 125 percent of nameplate current for motors marked with a 1.15 service factor or a 40 degrees C temperature rise.

Compressor protection, 175 percent

NEC 440.22(A) permits short-circuit protection for an air-conditioning compressor at up to 175 percent of rated-load current, increased to 225 percent if the unit will not start.

Communications cable separation

NEC 800.133(A)(1) requires communications cables to be separated by at least 2 in. from power conductors, Class 1 circuits and non-power-limited fire alarm conductors unless a barrier separates them.

Intersystem bonding termination

NEC 250.94 requires a terminal bar at the service to bond communications, community antenna television and other systems, providing a common point for intersystem bonding.

Class 2 circuit limits

NEC Article 725 defines Class 2 circuits as limited-energy circuits whose power does not exceed the values in Tables 725.121, permitting reduced wiring and separation requirements.

Oklahoma electrical licensing authority

Electrical licenses in Oklahoma are issued by the Construction Industries Board under the Oklahoma Electrical Licensing Act, located in Title 59 of the Oklahoma Statutes, Sections 1680 through 1697.

Oklahoma apprentice supervision

Oklahoma requires registered electrical apprentices to work under the supervision of a licensed journeyman or contractor, with apprentice registration filed with the Construction Industries Board.