Understanding the fundamental concepts and terminologies of electrical engineering is very important for anyone working with electrical systems or even just using everyday electronic devices. In this article, we’ll briefly explain almost all electrical definitions and terms to help understanding general used and technical terms in commercial buildings, plants and refineries projects at site.
Electrical Definitions and Terms.
Understanding electricity is important in today’s world, whether you’re an electrician, engineer, or simply someone who wants to comprehend how things work. However, navigating the world of electrical terminology can be difficult, especially for beginners. Come! Let’s catch the full list of electrical terms and definitions.
1. Ampacity.
Ampacity refers to the maximum current-carrying capacity of a conductor, typically expressed in amperes (A). It represents the amount of electrical current that a conductor can safely carry without exceeding its temperature rating or causing damage to the insulation.
2. Ammeter.
An instrument for measuring the magnitude of electrical current. Portable test instruments are generally a clamp-around type device which has a digital or analog indication.
3. Audio and Visual Voltage Tester.
A tester which provides an audio tone and visual indication when in close proximity to AC energized systems.
4. Appliance.
An appliance is a device or piece of equipment designed for a specific function or task, typically used in a household, commercial, or industrial setting.
5. Circuit Breaker.
A device designed to open and close a circuit by manual or electrical means. It is capable of clearing short circuit currents without damage when properly applied within its rating.
6. Cutout Box.
A cutout box, also known as a junction box or pull box, is an enclosure used in electrical installations to house and protect electrical connections, wiring splices, and junctions.
7. Dead Front.
A dead front is defined as panel or cover of an electrical enclosure that conceals live electrical components and prevents direct access to them when closed.
8. Panelboard.
A panelboard, also known as a distribution board or breaker panel. It is an electrical enclosure that included busses, automatic overcurrent devices, circuit breakers, fuses, or other protective devices used to control and distribute electrical power within a building or structure.
9. Contactor.
A device for repeatedly establishing and interrupting normal load current in an electric power circuit.
10. Demand Factor.
The term demand factor is defined as the ratio of the maximum actual load of a system or part of a system to the total connected load or maximum potential load.
11. Dwelling Unit.
A dwelling unit is defined as single residential unit or living space that is designed, constructed, or used as a place of residence by one or more individuals or families.
12. Current.
Measure of electrical flow. Measured in Amps or Amperes.
13. De-energized.
Free from any electrical potential.
14. Feeder.
In electrical engineering and power distribution systems, a term feeder is defined as a circuit or conductor that carries electrical power from a source, such as a substation or distribution panel, to one or more load centers, distribution points or final branch circuit.
15. Bonding.
Bonding is defined as connection of metallic components to create a low-impedance path for electrical currents. Metallic components such as enclosures, conduits, raceways, panels, and equipment are interconnected using conductive materials such as wires, straps, or bars.
16. Overload.
An overload term is defined as a condition in an electrical circuit where the current flowing through the circuit exceeds its rated capacity or design limits. Remember, short circuit and ground fault are not overload.
17. Bonding Jumper.
A bonding jumper is a conductive element (conductor) used to establish an electrical connection between two metallic components or enclosures. Its primary purpose is to ensure electrical continuity.
18. Branch Circuit.
A branch circuit is an electrical circuit that is between distribution panel or subpanel and final outlets. It provides electrical power to outlets, fixtures, or devices within a building or structure.
19. Plenum.
A plenum term is defined as a space or chamber, where one or more air ducts are connected. It is used for airflow distribution or as a pathway for heating, cooling, or ventilation systems in the building construction and HVAC (Heating, Ventilation, and Air Conditioning) systems. The term “plenum” is derived from the Latin word for “full,” reflecting its function as a space that is typically filled with air or other gases.
20. Raceway.
In electrical engineering and construction, a raceway term is defined as a enclosed channel or conduit used to protect, route, and organize electrical wiring or cables. Raceways are designed to provide a safe and organized pathway for conductors while protecting them from physical damage, environmental hazards, and interference.
21. Receptacle.
A receptacle, also known as an outlet or socket. It is a device installed in electrical wiring systems to provide a point for connecting electrical plugs and accessing electrical power. Receptacles are commonly found in residential, commercial, and industrial buildings and are used to power various electrical devices and appliances.
22. Voltage.
Voltage is also known as electric potential difference. It is a measure of the electric potential energy per unit charge between two points in an electrical circuit. It is the force that drives electric charges to move through a conductor in a circuit. Voltage is measured in volts (V).
23. Switchgear.
Switching and interrupting devices, associated control, instrumentation, metering, protective and regulating devices, interconnections, supporting structures, and accessories, used primarily in the distribution of electrical energy.
24. E-2 Starter.
E-2 Starter is defined as a NEMA rated combination fuse and high-voltage contactor used on high-voltage circuits.
25. Electrical Room.
Electrical room term is defined as indoor electrical area containing high voltage and/or low voltage electrical equipment.
26. Switch Stick/Hot Stick.
An insulated rod, tube, or pole used for the purpose of testing or operating equipment while it is energized, assumed to be energized, or in close proximity to other energized components. It allows the individual using this device to remain a safe distance away from the energized electric equipment.
26. Cell Battery Voltage.
Cell Battery Voltage is defined as the potential between the cell terminals created by the chemical reaction within a disconnected electrolytic cell.
27. Cell Bypass (Shorting) Switch.
Cell Bypass (Shorting) Switch is a permanently mounted switch that when closed carries the cell line current and allows the cell line process to continue when removing an electrolytic cell. The Cell Bypass Switch is mechanically interlocked with the Cell Isolating Switches.
28. Cell (Electrolytic).
Cell (electrolytic) term is defined as a tub and head assembly in which electrochemical reactions are created by applying DC current for the purpose of producing usable materials.
29. Cell Line Working Zone (CLWZ).
Cell Line Working Zone (CLWZ) is defined as the cell line working zone is the space envelope wherein operation or maintenance is normally performed on or in the vicinity of exposed energized surfaces of the electrolytic cell lines or their attachments.
30. Electrical Equipment.
Industrial Electrical Equipment is defined Electrical equipment such as switchgear, motor control centers, power distribution centers, panel boards, circuit breakers, motors, transformers, etc., designed for use in an industrial environment, indoors and outdoors.
31. Cell Line.
Cell Line is defined as an assembly of electrically interconnected electrolytic cells.
32. Cell Flexible Cables.
Cell Flexible Cables are defined as conductors between the Cell Isolating (Disconnecting) Switch and the electrolytic cell termination posts.
33. Cell Isolation Switch.
Cell Isolating (Disconnecting) Switch is a set of two switches that operate together to connect and/or disconnect a cell from the DC power of the cell line copper bus work. The Cell Isolating Switches are mechanically interlocked with the Cell Bypass Switch.
34. Cell Voltage.
Cell Voltage is defined as the dc voltage between the positive (Anode) and negative (Cathode) buses supplying power to a single electrolytic cell.
35. De-energized.
De-energized – Applies to cell lines. A state of having no external source of dc power to the cell line. (CAUTION: the Cell Battery Voltage is still present.)
36. Energized.
Applies to cell lines. Applying an external source of dc power to the cell line. Energized can also be defined as electrically connected to a source of electrical energy.
37. Grounded.
Grounded (Earthed) is defined as connected to ground (earth) or a conductor body that extends the ground (earth) connection.
38. Guarded.
Guarded is covered, shielded, fenced, enclosed or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.
39. Insulated.
Insulated (electrically isolated) is defined as separated from other conducting surfaces by a dielectric substance or air space permanently offering a high resistance to the passage of current.
40. Power Bus Compartment.
Power Bus Compartment is defined as a segregated section of a rectifier dedicated to housing the bus bar, SCRs, transformer connections, and other current carrying, exposed parts.
41. Rectifier.
Rectifier is defined as an assembly of electrical and electronic components used to convert alternating current (ac) to direct current (dc).
42. Safeguard.
Safeguard is a precautionary measure or stipulation, or a technical contrivance to prevent accidents.
43. Safe Work Practices.
Safe Work Practices is the operating and maintenance procedures and controls written to reduce personnel hazards and minimize risk.
Grounded or Earthed – Connected to the general mass of earth.
High Voltage—1001 volts and higher.
Insulated Tools – See Voltage rated tools.
Isolation – Free from electrical sources by means of a device or procedure that establishes a break in the electrical circuit.
Isolation Mechanism—The operating mechanism, device and/or procedure required to electrically isolate from the source of electrical energy, and allow the equipment to be physically locked in the safe position.
Low Voltage—Between 31 and 1000 volts.
On/Off (start/stop)—Normal control means to shutdown or startup an electrical device. Example: pushbutton, DCS, etc.
Physical Break—The withdrawing of a withdrawable electrical device, or the disassembly of a permanently connected assembly (bus bar link, cable termination, etc.) to provide electrical isolation.
Qualified Contractor—One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training from their employer to recognize and avoid the hazards involved.
Qualified Person – One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved.
Fully Authorized – A competent person who is authorized to operate, perform electrical maintenance tasks and electrical system isolations as documented by the qualified level electrical safety awareness and aptitude training certificate. This authorization category is generally site specific.
Qualified Electrical – A technician or Engineer with additional training, qualifications and experience in Operating, Maintaining and Earthing/Grounding Electrical Systems. This is the highest level of electrical authorization.
Qualified Maintenance Personnel – Authorized to perform prescribed maintenance tasks on specified equipment.
Qualified Operator – Authorized to operate specified equipment.
Arc-fault circuit interrupter – An arc-fault circuit interrupter (AFCI) is a type of electrical safety device designed to detect and mitigate the risk of electrical fires caused by arcing faults in residential and commercial electrical circuits.
Site Specific Arc Flash Assessment – Conducted by Electrical Engineering to determine the appropriate PPE and/or operating restrictions for operating and maintaining electrical equipment. The assessment uses the calculated incident energy level as a starting point and considers:
Lighting Outlet – A lighting outlet is a type of electrical outlet or fixture designed to provide illumination in a building or structure. It is used for the direct connection of lamp holder or or luminaire. Lighting outlets are installed at various locations throughout residential, commercial, and industrial spaces to support lighting fixtures, lamps, or bulbs.
Switchyard – Switchyard can be defined as outdoor electrical areas containing electrical equipment. This may include exposed, uninsulated equipment.
Voltage – Measure of electrical potential. Measured in Volts.
Voltage Rated tools – Hand tools or devices that are designed to come in contact with energized equipment. Voltage level limits must be identified on the tool. These may also be referred to as insulated tools.
Voltmeter – An instrument for measuring the magnitude of potential difference.
Racking – Engaging or dis-engaging of an electrical device from a bus connection; for example, Circuit Breakers, Contactors, VT/PT, etc.
Competent Person – A trained person having sufficient technical knowledge and experience to complete an assigned task safely.