Understanding electrical terms helps people communicate effectively with electricians and other professionals in the field. It provides definitions for words and phrases that are specific to the electrical field and can be unfamiliar to others. The following are the lists of most common terms and acronyms used in circuit breakers, components of switchboards, and electrical engineering field:

Circuit Breaker Acronyms

ACB (Air Circuit Breaker) – an electrical protection device used for short circuit and overcurrent protection up to 15kV with amperes rating of 800A to 10kA.

CB (Circuit Breaker) – an electrical switch that automatically cuts off the flow of electricity in a circuit to protect people and equipment from damage caused by an overload, short circuit, or other electrical fault.

MCB (Miniature Circuit Breaker) – a type of electrical protection device that has rated current not more than 125A. Used mainly for domestic.

MCCB (Molded Case Circuit Breaker) – another type of electrical protection device that has rated current up to 1600A and functions when load current exceeds the limit of a miniature circuit breaker. Mainly used for industrial.

RCBO (Residual Current Circuit Breaker with Overcurrent Protection) – an electrical safety device that provides protection against residual current, short circuit, and overload. RCBO can do what RCD can do and is essentially a combination of MCB and RCCB.

RCCB (Residual Current Circuit Breaker) – an electrical wiring device that disconnects the circuit whenever there is leakage of current flow through the human body or the current is not balanced between the phase conductor. It is generally used in series with an MCB.

RCD (Residual Current Device) – an electrical protection device that is used to protect against electric shocks, residual currents, and earth faults.

SPD (Service Protection Device) – is a circuit breaker designed to interrupt a fault current between your main switchboard and the network.

Other Types

AC (Alternating Current) – a type of electrical current in which the direction of the flow of electrons switches back and forth at regular intervals or cycles. The current periodically reverses direction and changes its magnitude continuously with time.

AEMO (Australian Energy Market Operator) – responsible for operating Australia’s largest gas and electricity markets and power systems. They perform development and planning functions.

BESS (Battery Energy Storage System) – an advanced technological solution that allows energy storage in multiple ways for later use. It enables energy from renewables like solar and wind to be stored and then released.

BMS (Battery Management System) – a technology dedicated to the oversight of a battery pack, which is an assembly of battery cells, electrically organized in a row x column matrix configuration to enable delivery of a targeted range of voltage and current.

dB (Decibels) – a relative unit of measurement to one-tenth of a bel (B). It expresses the ratio between two physical quantities, usually amounts of acoustic or electric power, or for measuring the relative loudness of sounds.

DC (Direct Current) – an electric current that is uni-directional, so the flow of charge is always in the same direction.

DOD (Depth of Discharge) – a measurement of how much energy has been used from a battery relative to its total capacity. It’s usually expressed as a percentage or in amp-hours (Ah).

EMC (Electromagnetic Compatibility) – the ability of electrical and electronic equipment to operate without interfering with other equipment or the environment. It is a quality description of a product, similar to reliability or performance.

EMF (Electromagnetic Field) – a property of space caused by the motion of an electric charge.

FAT (Factory Acceptance Test/ing) – a test that runs on the equipment or components before they are delivered to their intended destination.

FCAS (Frequency Control Ancillary Services) – a process used by the energy market operator to maintain the frequency of the system within the normal operating band around 50 cycles per second.

FMECA (Failure Modes, Effects, and Criticality Analysis) – a systematic method for identifying and assessing potential failures in systems and equipment.

HV (High Voltage) – a term used in electrical engineering to describe a system that carries more than 1,000 volts between conductors and 600 volts between conductors and ground.

Hz (Hertz) – the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second.

IPxx (Ingress Protection Rating to AS 60529) – a standardized way to measure how well electrical enclosures protect against the intrusion of foreign objects, moisture, and water.

ITC (Inspection and Test Checklist) – a document that records the results of inspections and tests performed on a project, process, or system.

ITP (Inspection and Test Procedure) – an inspection checklist of required inspections. It lists task inspections and provides an easy-to-follow plan to improve quality assurance.

kW (Kilowatt) – a unit of measurement for the rate of power an electrical device or load uses. A kilowatt is 1000 watts (W).

kWh (Kilowatt Hour) – the measure of energy usage of an electrical device or load. The higher the rate of power (kW) and the longer it is used (hours), the more electricity it consumes (kWh).

LAN (Local Area Network) – a group of devices connected in a single location, such as a home, office, or school, that allows users to share resources and communicate.

LED (Light Emitting Diode) – a semiconductor device that produces light when an electrical current passes through it.

LV (Low Voltage) – a term used to describe electrical systems that operate at relatively low voltages, typically up to 1,000 volts AC or 1,500 volts DC.

MASS (Market Ancillary Service Specification from AEMO) – a document from AEMO that outlines the requirements that participants in Frequency Control Ancillary Service (FCAS) markets must meet.

MSB (main switchboard) – an electrical device that is used to switch and protect the electrical load sub-systems.

NSWSIRR (New South Wales Service and Installation Rules) – rules that set out the minimum standards for providing safe, reliable, and efficient connection services to customer premises in New South Wales, Australia.

PLC (Programmable Logic Controller) – a digital computer that controls industrial processes, such as machines, assembly lines, and robotic devices.

PQ (Power Quality) – a measure of how well a power supply system’s voltage, frequency, and waveform meet established standards.

RTU (Remote Terminal Unit) – an electronic device that collects and processes data from sensors and other devices in industrial control systems.

SAT (Site Acceptance Test/ing) – a series of procedures and tests that verify a system or equipment is ready for use at a customer’s site.

SCADA (Supervisory Control and Data Acquisition) – a system of software and hardware elements that allows organizations to control and monitor industrial processes.

SLD (Single Line Diagram) – a simplified representation of an electrical system that uses lines and symbols to show the system’s connections and nodes.

SOC (State of Charge) – a measurement of the amount of energy remaining in a battery relative to its maximum capacity.

SOH (State of Health) – a measurement of a battery’s condition relative to its ideal state. It takes into account factors like internal resistance, capacity fade, and the battery’s ability to deliver power.

WAN (Wide Area Network) – a collection of local-area networks (LANs) or other networks that communicate with one another.

Repeat information you don’t know more often, and information you know very well less often. This glossary can help people who are new to the industry or working on a home project understand the terms used by electricians. There might be words that are not said in this article but the importance of having these knowledge is to “remember” when you encounter these words in electrical engineering industry.