ID Electrician flashcards

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

Ohm's law

The current through a conductor equals the voltage across it divided by its resistance, written as I = E / R, where E is in volts and R in ohms.

NEC Chapter 8 scope

Chapter 8 covers communications systems such as telephone, cable television, and network cabling, and it stands alone rather than being supplemented by Chapters 1 through 7.

Article 100 definitions

Article 100 defines standard Code terms such as branch circuit, outlet, and grounded conductor so that requirements are applied consistently throughout the NEC.

Status of NEC annexes

The annexes that follow Chapter 9 are informational only and are not enforceable as code requirements unless a jurisdiction specifically adopts them into law.

Balanced three-phase power

For a balanced three-phase load, power in watts equals 1.732 times the line voltage times the line current times the power factor.

Parallel resistance rule

For resistances in parallel, the reciprocal of the total equals the sum of the reciprocals of the individual resistances, and the total is less than the smallest branch.

Box fill per 14 AWG

Each 14 AWG conductor in a box counts as 2.0 cubic inches of volume under Table 314.16(B), before adding allowances for devices, clamps, and equipment grounds.

Conduit fill 40 percent

Chapter 9 Table 1 permits a raceway to be filled to 40 percent of its interior cross-sectional area when three or more conductors are installed.

Working space requirements

Equipment that may be examined while energized requires clear space in front of it that is 30 inches wide, 3 feet deep, and 6.5 feet high.

NM cable support spacing

Nonmetallic-sheathed cable must be secured within 12 inches of each box and at intervals not exceeding 4.5 feet along the length of the run.

Dwelling receptacle spacing

In dwelling units, receptacle outlets along walls must be arranged so that no point on the wall is more than 6 feet from an outlet.

Grounded conductor identification

The grounded, or neutral, conductor must be identified by a white finish, a gray finish, or three continuous white stripes along its entire length.

Next size up rule

Where a conductor's ampacity does not match a standard fuse or breaker rating, the next higher standard rating may be used, up to 800 amperes.

Continuous load 125 percent

Overcurrent devices and conductors serving continuous loads must be sized at not less than 125 percent of the continuous load plus 100 percent of the noncontinuous load.

Standard overcurrent device ratings

Standard ampere ratings include 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, and 100 amperes, as listed in Section 240.6(A).

Small conductor protection limits

Unless a specific permission applies, 14 AWG copper is limited to 15 amperes, 12 AWG to 20 amperes, and 10 AWG to 30 amperes of overcurrent protection.

Class A GFCI trip level

A Class A ground-fault circuit interrupter trips when it senses a ground-fault current of 4 to 6 milliamperes, providing protection for personnel.

Feeder versus branch circuit

A feeder is the set of conductors between the service equipment or derived source and the final overcurrent device; the branch circuit lies beyond that device.

Ground rod 25 ohm rule

A single driven ground rod must measure 25 ohms or less to earth; if it does not, a supplemental electrode must be installed and bonded to it.

Equipment grounding conductor sizing

Table 250.122 sizes equipment grounding conductors based on the rating or setting of the overcurrent device protecting the circuit, not on conductor ampacity.

Main bonding jumper

The main bonding jumper connects the grounded service conductor to the service equipment enclosure and grounding electrode conductor, and is installed only at the service.

Separate neutrals in subpanels

Neutral and equipment grounding conductors must be kept separate in panelboards and subpanels downstream of the service, with no neutral-to-ground bonding connections.

Grounding electrode conductor sizing

Table 250.66 sizes the grounding electrode conductor according to the size of the largest ungrounded service-entrance conductor supplied by the service.

Motor overload protection

Motor overload protection is generally sized at no more than 125 percent of the motor nameplate full-load ampere rating, as required by Section 430.32.

Motor branch circuit conductors

Branch-circuit conductors supplying a single motor must have an ampacity of at least 125 percent of the motor full-load current from Table 430.250.

Motor disconnecting means location

Each motor must have a disconnecting means within sight of and within 50 feet of the motor, or one that can be locked in the open position.

Motor short-circuit protection

Table 430.52 sizes motor short-circuit protection at a percentage of full-load current: 250 percent for an inverse-time breaker and 175 percent for a dual-element fuse.

Article 440 equipment

Article 440 covers hermetic refrigerant motor-compressors and air-conditioning equipment, which use rated-load current instead of the standard motor full-load current tables.

Idaho Electrical Board

The Idaho Electrical Board, within the Division of Occupational and Professional Licenses, administers electrician licensing and adopts the electrical code by rule.

Idaho license categories

Idaho issues apprentice, journeyman, master, and limited or specialty electrician licenses, each carrying its own experience, supervision, and examination requirements.

Idaho electrical statutes

Idaho's electrical licensing statutes are codified in Title 54, Chapter 10 of the Idaho Code, which establishes the Electrical Board and its licensing authority.

Idaho code adoption

Idaho adopts the National Electrical Code by Board rule with state amendments, while local authorities having jurisdiction issue permits and perform inspections of installations.