OR Electrician key terms

The maximum current, in amperes, that a conductor can carry continuously under stated conditions of use without exceeding its rated temperature. It depends on conductor size, insulation type, ambient temperature, and how many conductors share a raceway.

A fuse or circuit breaker that automatically opens a circuit when current exceeds a predetermined safe level, protecting conductors, equipment, and people from overheating, arcing, and fire.

A device that continuously compares current on the ungrounded and grounded circuit conductors and trips when the imbalance indicates current leaking to ground, reducing the danger of electric shock.

A circuit breaker or outlet device that recognizes the current signature of an unintended electric arc and opens the circuit to prevent the arc from igniting nearby materials.

The conductor that connects the metal frames and enclosures of equipment to the grounding electrode system so fault current has a low-impedance path back to the source and the overcurrent device trips.

Permanently joining metal parts with conductors or approved fittings so they form an electrically continuous path capable of safely carrying any fault current likely to be imposed on them.

The circuit conductors between the final overcurrent device protecting the circuit and the outlets, devices, or utilization equipment supplied by that circuit. General-purpose receptacles and lighting are typical examples.

All circuit conductors between the service equipment, the source of a separately derived system, or another power supply and the final branch-circuit overcurrent device protecting the circuit.

A load whose maximum current is expected to continue for three hours or longer. Conductors, overcurrent devices, and certain equipment serving it must generally be sized at 125 percent of the load.

The clear area that must be kept in front of electrical equipment so a person can safely work on it; its depth depends on voltage and on conditions on the opposite side of the space.

The total volume, in cubic inches, that each conductor, device, fitting, and equipment ground counts against when determining whether an outlet box is large enough for its contents.

A single unit that provides complete and independent living facilities for one or more people, with permanent provisions for living, sleeping, cooking, and sanitation.

The circuit conductor that is intentionally connected to earth at the source, commonly called the neutral, which normally carries the return current of a 120-volt circuit.

Oregon's electrical code, made up of the current edition of NFPA 70 plus the state's amendments, adopted through the Building Codes Division and enforced for electrical installations throughout Oregon.

The principle that Oregon's building and electrical codes apply the same way everywhere in the state; local governments may not adopt or enforce a conflicting electrical code of their own.

Oregon's electrical safety statute. It establishes licensing of electricians and contractors, permit requirements, inspection authority, and enforcement powers administered by the Building Codes Division.

The administrative rules of the Oregon Electrical and Elevator Board. These rules fill in the statute with details on license types, renewal, continuing education, supervision, and disciplinary procedures.

The Oregon board whose members advise the Building Codes Division on electrical and elevator standards, propose rule changes, and take part in licensing and disciplinary decisions.

An Oregon license that permits a person to perform all classes of electrical work without supervision, usually obtained by completing an approved apprenticeship and passing the journeyman examination.

An Oregon license restricted by rule to one narrow kind of work, such as signs or work in a manufacturing plant, rather than the full scope covered by a general journeyman.

The licensed individual designated by an electrical contractor to ensure that the firm's electrical work is performed correctly and in compliance, as Oregon law requires for contractor licensure.

A business holding a state license to offer or perform electrical work for others in Oregon. The firm must designate a supervising electrician and meet the board's licensing requirements.

A person enrolled in an approved electrical training program who may perform electrical work only while supervised by a licensed journeyman or supervising electrician, as board rules prescribe.

Authorization issued before covered electrical work begins, and the follow-up review by a state or local electrical inspector who verifies that the completed installation meets code.

The fixed relationship among voltage, current, and resistance in a DC circuit: voltage equals current multiplied by resistance. Knowing any two values lets you calculate the third.

A circuit with a single current path. The same current flows through every component, the voltages add up to the source voltage, and the total resistance is the sum of the parts.

A circuit with two or more current paths. The voltage is the same across each branch, branch currents add to the total, and the total resistance is always less than the smallest branch resistance.

In an AC circuit, the ratio of true power in watts to apparent power in volt-amperes. A low power factor means more current is needed to deliver the same useful work.

Voltage lost as current travels through the resistance and reactance of circuit conductors. Large drops cause dim lighting and poor motor performance, so long runs often need larger conductors.

The ratio of the maximum demand on a system, or part of it, to the total connected load. Applying it recognizes that not everything runs at full load at the same time.

The NEC's preset approach to sizing dwelling feeders and services, adding general lighting, small-appliance, laundry, and named appliance loads and then applying the permitted demand factors.

An alternative calculation for dwelling units that uses a volt-ampere allowance per square foot plus specific allowances for appliances, heating, and cooling and a demand factor on the total.

A procedure in which a circuit is opened, then locked and tagged by the worker so it cannot be re-energized while that person is working on or near the equipment.

An explosive release of energy when current arcs through air between energized parts, producing intense heat, blinding light, molten metal, and a pressure wave that can seriously injure workers.

The arc-rated clothing, insulating gloves, face shields, hard hats, and other gear a worker wears to reduce injury from shock, burns, and flying debris on the job.

A distance measured from exposed energized parts that a person may not cross unless qualified and protected as required, set by voltage and by shock or arc-flash risk.

A required construction-site program of documented inspections and continuity tests on cord sets and cord-and-plug equipment to confirm the grounding conductor is intact before use.

A test that applies a high DC voltage with a megohmmeter to measure leakage through insulation, revealing moisture, contamination, or damage that a simple continuity check would miss.