The efficiency of a system in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed.

Electrical energy is energy derived as a result of movement of electrons, energy that has been converted from electric potential energy.

In an electric power system, a fault or fault current is any abnormal electric current.

An electrical grid is an interconnected network for electricity delivery from producers to consumers.

A ground fault (earth fault) is any failure that allows unintended connection of power circuit conductors with the earth.

Electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied.

Electrical insulation papers are paper types that are used as electrical insulation in many applications due to pure cellulose having outstanding electrical properties.

Electrical measurements are the methods, devices and calculations used to measure electrical quantities.

An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances).

An electrical outlet tester, receptacle tester, or socket tester is a small device containing a power plug and three indicator lights, used for quickly detecting some types of incorrectly-wired electrical wall outlets.

The output of a generator or power plant usually measured in megawatts (MW).

A persistent fault is present regardless of power being applied.

Electrical polarity is a term used throughout industries and fields that involve electricity.

Reactance is the opposition of a circuit element to the flow of current due to that element's inductance or capacitance.

Electrical resistance of an object is a measure of its opposition to the flow of electric current.

Electrical safety is a system of organizational measures and technical means to prevent harmful and dangerous effects on workers from electric current, arcing, electromagnetic fields and static electricity.

Electrical safety testing is essential to ensure safe operating standards for any product or establishment that uses electricity.

Electrical steel (lamination steel, silicon electrical steel, silicon steel, relay steel, transformer steel) is an iron alloy tailored to produce specific magnetic properties: small hysteresis area resulting in low power loss per cycle, low core loss, and high permeability.

A substation is a part of an electrical generation, transmission, and distribution system.

Electrical susceptance (B) is the imaginary part of admittance, where the real part is conductance. In SI units, susceptance is measured in siemens.