AK Electrician flashcards

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

Ohm's Law

The relationship among voltage, current, and resistance in a circuit, expressed as E = I × R. Knowing any two quantities lets you solve for the third.

Series Circuit Resistance

In a series circuit, current is common to all elements and total resistance equals the sum of the individual resistances. Total voltage divides across the elements.

Parallel Circuit Resistance

In a parallel circuit, voltage is common across branches and total resistance is less than the smallest branch resistance, found by summing reciprocals.

RMS Value

The effective value of an alternating current that produces the same heating as an equal direct current. For a sine wave it equals peak divided by the square root of two.

Inductive Reactance

Opposition to alternating current caused by inductance, calculated as two pi times frequency times inductance. It increases as frequency rises and causes current to lag voltage.

Three-Phase Power

Real power in a balanced three-phase circuit equals the square root of three times line voltage times line current times power factor.

Dwelling Lighting Load

The general lighting and receptacle load for a dwelling is computed at three volt-amperes per square foot of floor area before demand factors are applied.

Small-Appliance Circuits

Dwellings require at least two 20-ampere small-appliance branch circuits, each calculated at 1500 volt-amperes for service load purposes.

Largest Motor Addition

When calculating a service or feeder, the largest motor load is increased by 25 percent to account for starting current.

Branch-Circuit Rating

The rating of a branch circuit is determined by the ampere rating of its overcurrent protective device, not by the conductor size alone.

Raceway Fill Percentage

The maximum portion of a raceway interior cross section that conductors may occupy, such as 40 percent for three or more conductors in a run.

Box Fill Calculation

Box volume must accommodate each conductor, device, fitting, and grounding conductor using the volume allowances assigned by conductor size.

360-Degree Bend Rule

No more than 360 degrees of bends, whether made in the raceway or by fittings, is permitted between pull points in a run.

Expansion Fitting Use

Expansion fittings accommodate movement where a raceway crosses a building expansion joint or where thermal expansion and contraction are expected.

Conductor Ampacity

The current a conductor can carry continuously under stated conditions, taken from ampacity tables and adjusted for ambient temperature and conductor count.

Parallel Conductor Rules

Conductors run in parallel must have the same length, material, size, insulation, and termination so current divides equally among them.

Receptacle Spacing

Along dwelling unit wall space, receptacle outlets must be placed so no point on the floor line is more than six feet from an outlet.

Counter Receptacle Spacing

Kitchen and similar countertop receptacles must be installed so no point along the counter is more than 24 inches from a receptacle outlet.

Conductor Color Identification

The grounded conductor is identified white or gray, the equipment grounding conductor green or bare, and ungrounded conductors by other approved colors.

Standard OCPD Ratings

Overcurrent devices are made in standard ratings such as 15, 20, 30, 40, 50, 60, 70, 80, 90, and 100 amperes, used for selection and sizing.

GFCI Protection Purpose

A ground-fault circuit interrupter detects small line-to-ground current imbalances and opens the circuit to protect people from electric shock.

AFCI Protection Purpose

An arc-fault circuit interrupter recognizes the signature of dangerous arcing and de-energizes the circuit to reduce the risk of fire.

Equipment Grounding Conductor

A conductor that connects non-current-carrying metal parts to the grounding system and provides a low-impedance fault path to operate overcurrent devices.

Motor Branch Conductor Sizing

Motor branch-circuit conductors must have an ampacity of at least 125 percent of the motor full-load current taken from the code motor tables.

Motor Overload Protection

Overload protection guards the motor against excessive current from overloading, while branch-circuit protection handles short circuits and ground faults.

Motor Disconnect Location

A motor disconnecting means must be within sight of the motor and its controller, or capable of being locked in the open position.

Motor Full-Load Current Source

For sizing motor conductors and protection, full-load current is read from the code motor tables rather than from the motor nameplate.

Hazardous Location Classes

Class I covers flammable gases and vapors, Class II covers combustible dust, and Class III covers easily ignitable fibers or flyings.

Division 1 Versus Division 2

Division 1 means the hazardous condition exists under normal operation; Division 2 means it exists only under abnormal or fault conditions.

Wet Location Requirements

Wet locations require enclosures and fittings listed for wet use, with gaskets and weatherproof construction that shed water.

Authority Having Jurisdiction

The organization or individual responsible for enforcing the electrical code, interpreting its provisions, and approving equipment, materials, and installations.

Concealed Work Inspection

Electrical work that will be concealed must be inspected and approved before walls, ceilings, or other coverings are installed over it.

Alaska Electrician Licensing

Alaska requires electricians to hold a state journeyman or master license, or to work as a registered apprentice under a licensed electrician's supervision.

Electrical Contractor Administrator

An Alaska electrical contractor must be licensed and must employ a licensed administrator who is responsible for code compliance of the contractor's work.