KY Electrician flashcards

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

Chapter 8 independence

NEC 90.3 states that Chapter 8, covering communications systems, is independent of Chapters 1 through 7; those chapters apply to Chapter 8 wiring only where Chapter 8 specifically references them.

Working space depth, 600 volts

Table 110.26(A)(1) requires clear working space depth of 3 ft for Condition 1, 3.5 ft for Condition 2, and 4 ft for Condition 3 in front of equipment rated 600 volts or less.

AHJ enforcement authority

Under NEC 90.4 the authority having jurisdiction enforces the Code, may interpret its provisions, approves listed materials and equipment, and may grant special permission where equivalent safety is provided.

NM cable securing

NEC 334.30 requires nonmetallic-sheathed cable to be secured within 12 inches of each box and at intervals not exceeding 4.5 feet along the length of the run.

Direct burial minimum cover

Table 300.5 requires 24 inches of cover for direct-buried cables in general, reduced to 12 inches for 120/240-volt residential branch circuits of 20 amperes or less that have GFCI protection.

Free conductor length

NEC 300.14 requires at least 6 inches of free conductor at each box, with at least 3 inches extending outside the box opening to allow for splices and terminations.

Ground rod resistance rule

NEC 250.53(A)(2) requires a single 8-foot rod to show 25 ohms or less resistance to earth; if it does not, a second electrode at least 6 feet away must be added.

GEC versus EGC sizing

The grounding electrode conductor is sized from Table 250.66 using the largest service-entrance conductor, while the equipment grounding conductor is sized from Table 250.122 using the rating of the overcurrent device.

Grounding electrode system

NEC 250.50 requires every grounding electrode present at a building or structure, such as water pipe, rod, concrete-encased, ring, or plate electrodes, to be bonded together into one grounding electrode system.

Small conductor protection limits

NEC 240.4(D) limits overcurrent protection to 15 amperes for 14 AWG copper, 20 amperes for 12 AWG copper, and 30 amperes for 10 AWG copper conductors, subject to the listed exceptions.

Ten-foot tap rule

NEC 240.21(B)(1) permits an unprotected tap up to 10 feet long when its ampacity is at least one-tenth the upstream device rating, it is enclosed in a raceway, and it ends at a single breaker.

Conductor adjustment, four to six

NEC 310.15(C)(1) requires ampacity to be reduced to 80 percent where 4 to 6 current-carrying conductors are installed in a single raceway or cable; 7 to 9 conductors require 70 percent.

Standard overcurrent device ratings

NEC 240.6(A) lists standard ratings including 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500 and 600 amperes.

Receptacle spacing 6-12 rule

NEC 210.52(A) requires dwelling receptacle outlets arranged so no point along a wall line is more than 6 feet from a receptacle, which yields at least one outlet for each 12 feet of wall space.

Box fill, 12 AWG

Table 314.16(B) assigns 2.25 cubic inches of box volume per 12 AWG conductor; each device yoke counts as two conductors and all equipment grounding conductors together count as one.

Raceway fill over two

NEC Chapter 9 Table 1 permits 53 percent fill for one conductor, 31 percent for two conductors, and 40 percent for three or more conductors installed in the same raceway.

Pull box straight pull

NEC 314.28(A)(1) requires the distance from a raceway entry to the opposite wall of a box to be at least eight times the trade size of the largest raceway for a straight pull.

Motor branch conductor sizing

NEC 430.22 requires branch-circuit conductors supplying a single continuous-duty motor to have an ampacity of at least 125 percent of the motor full-load current taken from the Code tables.

Motor overload protection setting

NEC 430.32 sets overload protection at 125 percent of nameplate current for motors with a marked service factor of 1.15 or higher, and 115 percent for motors without that marking.

Motor disconnect location

NEC 430.102(B) requires a motor disconnecting means, capable of being locked in the open position, to be within sight of and readily accessible from the motor and the driven machinery.

Class I Division 1

A Class I Division 1 location is one where ignitable concentrations of flammable gases or vapors may exist under normal operating conditions or may exist frequently because of repair, maintenance, or leakage.

Essential electrical system branches

NEC 517.30 divides the health care essential electrical system into the life safety branch, the critical branch, and the equipment branch, each serving defined loads from the essential power source.

Agricultural equipotential plane

NEC 547.10 requires an equipotential plane in conductive-floored areas where livestock are confined, bonded to the electrical system so voltage gradients that could shock animals are minimized.

PV conductor 125 percent

NEC 690.8 requires photovoltaic circuit conductors and overcurrent devices to be sized at not less than 125 percent of the maximum current calculated for that circuit.

Emergency system independence

NEC 700.10(A) requires emergency system wiring to be kept entirely independent of all other wiring and equipment, and not installed in the same raceways, boxes, or cabinets as normal power.

Pool equipotential bonding

NEC 680.26 requires metal parts of pool equipment, the pool water, and perimeter surfaces within the specified distance to be bonded to a common bonding grid using a copper conductor.

Class 2 circuit power limit

Class 2 circuits are power-limited circuits defined by NEC Chapter 9 Table 11(A), which limits their available power to 100 volt-amperes or less under the conditions the table specifies.

Fire alarm circuit types

Article 760 Part II covers non-power-limited fire alarm circuits (NPLFA) and Part III covers power-limited fire alarm circuits (PLFA), with different wiring methods and cable markings for each.

Communications grounding conductor

NEC 800.100 requires the communications grounding conductor to be at least 14 AWG copper, run as straight and short as practicable, and limited to a length of 20 feet.

Arc flash hazard label

NEC 110.16 requires switchboards, switchgear, panelboards, meter socket enclosures, and motor control centers likely to be examined while energized to be field-marked with an arc flash warning label.

Available fault current marking

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

Firestopping electrical penetrations

NEC 300.21 requires openings around electrical penetrations through fire-rated walls, floors, and ceilings to be firestopped with approved materials so the fire rating of the assembly is maintained.