800+ Electrical & Electronics Abbreviations with Full Forms

Electrical and electronics abbreviations are important for engineers and technicians to carry out everyday tasks. These abbreviations include both short forms and full forms of electrical and electronic terms.

These abbreviations provide standardized terms for electrical and electronic systems and components, establishing a universal language for clear and efficient communication. The short forms of electrical & electronic terms simplify the exchange of technical knowledge, reducing the risk of miscommunication and errors.

These abbreviations are widely utilized in fields such as:

• HVAC
• Telecommunications
• Manufacturing

These abbreviations ensure uniform understanding among specialists. By combining electrical short forms and full forms, engineers and technicians can work more efficiently, accurately, and productively in their daily technical and operational tasks.

Electrical and Electronics Engineering Abbreviations with Full Forms 

Below is a list of 800+ short form or abbreviations and their full forms commonly used in electrical and electronic engineering. The abbreviations are organized in ascending order, from A to Z, including numerical forms.

Electrical and Electronics Abbreviations in Alphabetical Order

A

Abbreviation	Full Form
A	Amperes, amps
App	Peak-to-peak amperes
AA	Anti-Aliasing
AAAC	All Aluminum Alloy Conductor
AAC	All Aluminum Conductor
AACSR	Aluminum Alloy Conductor Steel Reinforced
AAF	Anti-Aliasing Filter
ABC	Aerial Bundled Conductors or Cables
AB switch	Air Break switch
AC	Alternating current or voltage
A/C	Air Conditioning
ACAR	Aluminum Conductor Alloy Reinforced
ACB	Air Circuit Breaker
ACCB	Air Case Circuit Breaker
ACDB	Alternating Current Distribution Board
ACSR	Aluminum Conductor Steel Reinforced
ACVS	Air Conditioning & Ventilation System
ADC	Analog to Digital Converter
AF	Audio Frequency or Audible Frequency
AFC	Automated Frequency Control
AFC	Available Fault Current
AFCB	Arc Fault Circuit Breaker
AFCI	Arc Fault Circuit Interrupter
AFL	Amps Full Load
AFT	Automatic Fine Tuning
AGC	Automatic Gain Control
AGME	American Gear Manufacturer’s Association
AGPS	Assisted (or Aided) GPS
AH	Ampere-Hour Capacity of Batteries
AHU	Air Handling Unit
AI	Analog Input
AI	Artificial Intelligence
AIC	Ampere Interrupting Capacity
AL	Aluminum
ALCI	Appliance Leakage Current Interrupter
ALTC	Automatic Load Tap Changing
ALU	Arithmetic and Logic Unit
AMOLED	Active Matrix Organic Light Emitting Diode
ANSI	American National Standards Institute
AO	Analog Output
AoA	Angle of Arrival
AOI	Automatic Optical Inspection
AP	Access Point
APD	Avalanche Photo Diode
APFC	Automatic Power Factor Control
API	American Petroleum Institute, Application Program Interface
ARM	Advanced Reduced instruction set computing Machine
ARMS	Arc Flash Reduction Maintenance Switch
ASCII	American Standard Code for Information Interchange
ASIC	Application Specific Integrated Circuit
ASK	Amplitude Shift Keying
ASME	American Society for Testing and Materials
ASP	Application Service Provider
ASTA	Association of Short-circuit Testing Authorities
ATS	Automatic Transfer Switch
ATC	Automatic Temperature Control
ATMega	Microcontroller Chip created by Atmel in the megaAVR family
ATMEL	Advanced Technology for Memory and Logic
AV	Audio/Video
AVO-M	Ampere-Volt-Ohm Meter
AVR	Automatic Voltage Regulator
AWA	Aluminum Wire Armour
AWG	American Wire Gauge

B

Abbreviation	Full Form
B or b	Electrical Susceptance
Bar or bar	Pressure in atmospheres
BASEEFA	British Approvals Service for Electrical Equipment in Flammable Atmospheres
BBM	Break before Make
BCD	Binary Coded Decimal
BCR	Backspace Card Reader and Barcode Reader
BER	Bit Error Rate
BEV	Billion Electron Volts
BGA	Ball Grid Array
BIL	Breakdown Insulation Level
BJT	Bipolar Junction Transistor
BLAC	Brushless AC
BLDC	Brushless DC
BLDM	Brushless DC Motor
BOM	Bill Of Materials
BPF	Band Pass Filter
bps	Bit per second
Bps	Byte per second
BSI, BS, CP	British Standards Institution, or its publications
BTS	Base Transceiver Station
BTU	British Thermal Unit
BW	Bandwidth (difference between upper and lower limits of a band of frequencies)

C

Abbreviation	Full Form
C	Electrical Capacitance, Conduit
CA	Criticality Analysis
CAAPS	Circuit Assembly And Processing System
CACA	Totally Enclosed Air Circuit, Air Cooled
CACW	Totally Enclosed Air Circuit, Water Cooled
CAD	Computer Aided Design
CAN	Controller Area Network
CATV	Cable Television or Community Antennae Television
CB	Circuit Breaker
CBCU	Circuit Breaker Control Unit
CBI	Complementary Binary, Referring to a System of Codes
CBM	Certified Ballast Manufacturer
CBR	Constant Bit Rate
CC	Constant Current
CCCS	Current Controlled Current Source
CCD	Charge-Coupled Device
CCR	Central Control Room
CCT	Circuit (also: CIR, CKT)
CCTV	Closed Circuit Television
CCU	Central Control Unit
CD	Candela
CDMA	Code Division Multiple Access
CEGB	Central Electricity Generating Board (UK)
CENELEC	European Committee for Electrotechnical Standardization
cont.	Continuous Quantity
CFL	Compact Fluorescent Light or Compact Fluorescent Lamp
CG	Cable Glands
CIR	Circuit (also: CCT, CKT)
CISC	Complex Instruction Set Computer
CKT	Circuit (also: CCT, CIR)
CLF	Current Limiting Fuse
CMOS	Complementary Metal–Oxide Semiconductor
CMRR	Common Mode Rejection Ratio
CNC	Computer Numeric Control
COG	Chip-on-Glass
COR CU	Corrugated Copper
Cos θ	Power Factor
CPLD	Complex Programmable Logic Device
CPT	Control Power Transformer
CPU	Central Processing Unit
CRO	Cathode Ray Oscilloscope
CRT	Cathode Ray Tube
CSA, csa	Cross-Sectional Area
CSI	Current Source Inverter
CSP	Chloro Sulphonated Polyethylene
CSS	Computerized Synchronizing System
CT	Current Transformer
CU	Un-tinned Copper
CUWB	Copper Wire Braid
CVT	Constant Voltage Transformer

D

Abbreviation	Full Form
d	Day
DAC	Digital to Analog Converter
db(A)	Measurement Unit of Sound, Decibels, Absolute
dBm	Unit Level for Power Ratio Expressed in Decibels (dB) with Reference to 1 mW (milliwatt)
DB	Distribution Board
DC	Direct Current or Voltage
DCDB	Direct Current Distribution Board
DCS	Distributed Control System
DE	Drive End of a Shaft
DEMUX	Demultiplexer, Single Input into Multiple Outputs
DFT	Discrete Fourier Transform
DIA	Diameter
DIMM	Dual-In-Line Memory Module
DIN	Deutsches Institut für Normung (German Institute for Standardization)
DIP	Dual-In-Line Package
DIPS	Dual-In-Line Sockets
DLD	Digital Logic Design
DLL	Delay Locked Loop
DMA	Direct Memory Access
DMM	Digital Multimeter
DMS	Data Management System
DMT	Definite Minimum Time
DNC	Do Not Connect
DO fuse	Drop Out Fuse
DOL	Direct-On-Line Starting of Induction Motors
DOS	Disk Operating System
DP	Double Pole or Distribution Panel
DPDT	Double Pole, Double Throw
DPI	Dots Per Inch
DPIC	Double Pole Iron Clad
DPM	Digital Panel Meter
DPR	Dividing Pulse Relay
DPST	Double Pole, Single Throw
DRAM	Dynamic Random Access Memory
DRC	Design Rule Checking
DSP	Differential Signal Processing
DTMF	Dual Tone Multi-Frequency
DTL	Diode Transistor Logic
DTSP	Discrete Time Signal Processing
DUT	Device Under Test
DVM	Digital Volt Meter
DWR	Divided Winding Rotor Synchronous Generator

E

Here’s the table format for the abbreviations provided:

Abbreviation	Full Form
E	Earth or Ground
EB	Equipment Branch
EBIC	Electron-Beam-Induced Current
EC	Electrical Code, Electrical Contractor, or Electronic Commutator
ECAD	Electronic Computer-Aided Design
ECHA	Equipment Certified for Hazardous Areas
ECL	Emitter Coupled Logic
EEC	European Economic Community
EEMVA	Engineering Equipment and Materials Users Association
EEPROM	Electrically Erasable Programmable Read-Only Memory
EF	Exhaust Fan
EFT	Electrical Fast Transient
EHT	Extra High Tension
EHV	Extra High Voltage
EIEMA	Electrical Installation Equipment Manufacturer’s Association (UK)
ELCB	Earth Leakage Circuit Breaker
ELDC	Electric Double-Layer Capacitors (Supercapacitors)
ELEV	Elevator
ELV	Extra Low Voltage (less than 51 volts)
EM	Emergency
EMA	Ethylene Methyl Acrylate
EMC	Electromagnetic Compatibility
EMI	Electromagnetic Interference
EMF, e.m.f.	Electromotive Force
EMLDB	Emergency Lighting Distribution Board
EMR	Electro-Mechanical Relay
EMT	Electrical Metallic Tubing
EOCR	Electronic Overcurrent Relay
EOS	Electrical Over Stress
EP	Emergency Power
EPDM	Ethylene Propylene Diene Monomer
EPO	Emergency Power Off (Button or Switch)
EPR	Ethylene Propylene Rubber
EPROM	Erasable Programmable Read-Only Memory
ERA	Electrical Research Association (UK)
ERM	Electronic Restart Module
ESD	Emergency Shutdown, Electrostatic Discharge
ESL	Equivalent Series Inductance
ESP	Electric Submersible Pump
ESR	Equivalent Series Resistance
EST	Extra Super Tension
Ex (), Ex ‘ ’	Certification Symbol for Hazardous Area Equipment
EEx (), EEx ‘ ’	Certification Symbol for Hazardous Area Equipment (European Standards)
EV	Electron Volt, a Unit of Energy Similar to Joules
EWC	Electric Water Cooler
EWS	Engineering Work Station

F

Abbreviation	Full Form
F, f, Hz	Frequency, Fuse, Farad
FA	Fire Alarm
FAA	Fire Alarm Annunciator
FAT	Factory Acceptance Testing
FBA	Factory Built Assemblies
FBT	Flyback Transformer
FCEV	Fuel Cell Electric Vehicle
FCU	Feeder Control Unit
FDM	Frequency Division Multiplexing
FDNR	Frequency Dependent Negative Resistor
F and G	Fire and Gas
FEED	Front-End Engineering and Design of a Project
FET	Field Effect Transistor
FFC	Flexible Flat Cable
FFT	Fast Fourier Transform
FIFO	First-In, First-Out (a queue)
FILO	First-In, Last-Out (a stack)
FLA	Full Load Amperes
Flex	Flexible, used for cables
FM	Frequency Modulation
FMC	Flexible Metal Conduit
FPGA	Field-Programmable Gate Array
Freq	Frequency
FRLS	Fire Resistance Low Smoke
FSC	Final Sub Circuit
FSM	Finite State Machine
FSK	Frequency Shift Keying
FVC	Frequency to Voltage Converter

G

Abbreviation	Full Form
G, g	Electrical Conductance, or Ground
GBW	Gain Bandwidth Product
GCB	Gas Circuit Breaker
GCP	Generator Control Panel
GFCI	Ground Fault Circuit Interrupter
GFI	Ground Fault Interrupter
GIC	Generalized Impedance Converter
GIS	Gas Insulated Switchgear
gm	Transconductance
GND	Ground
GO	Gang Operated
GOR	Gas to Oil Ratio of Oil Well Fluids
GOS	Group Operated Switches
GPIO	General Purpose Input / Output
GPRS	General Packet Radio Service
GPS	Global Positioning System
GRMC	Galvanized Rigid Metal Conduit
GRP	Glass Reinforced Plastic
GSM	Global System for Mobile Communications
GSWA	Galvanized Steel Wire Armour
GSWB	Galvanized Steel Wire Braid
GTG, GT	Gas-Turbine Generator
GTO	Gate Turn-Off Thyristor
GUI	Graphic User Interface

H

Abbreviation	Full Form
h, hr	Hour
HART	Highway Addressable Remote Transducer
HBT	Heterojunction Bipolar Transistor
HCL	Hydrogen Chloride, Gas or Acid
HDMI	High-Definition Multimedia Interface
HED	Hall Effect Device
HEMT	High-Electron-Mobility Transistor
HF	High Frequency
hFE	Large-Signal Current Gain of a BJT
HMI	Human-Machine Interface
HOA	Hand-Off-Automatic Switch
HOFR	Heat and Oil Resisting, Flame Retardant
Hp	Horsepower, Unit of Power in FPS System
HPF	High Pass Filter
HRC	High Rupturing Capacity
HT	High Tension
HTS	High-Temperature Semiconductor
HUI	Human User Interface
HV	High Voltage, Above 600 Volts
HVAC	Heating, Ventilation, and Air Conditioning
Hz	Frequency in Cycles per Second, or Hertz

I

Abbreviation	Full Form
I	Current in amperes
IAC or Iac	Alternating current
IALA	International Association of Lighthouse Authorities
IC	Integrated Circuit
ICDB	Iron Clad Distribution Board
ICI	Imperial Chemical Industries plc (UK)
ICSP	In-Circuit Serial Programming
ICTP	Iron Clad Triple Pole
IDC, Idc	Direct current
IDMT	Inverse Definite Minimum Time
IEC	International Electrotechnical Commission
IEE	Institution of Electrical Engineers of UK
IEEE	Institute of Electronic and Electrical Engineers of USA
IF	Intermediate Frequency
IFT	Inverse Fourier Transform
IG	Isolated Ground
IGBT	Insulated-Gate Bipolar Transistor
IGFET	Insulated Gate Field Effect Transistor
I/O	Input or Output Signals or Quantity
IOT	Internet of Things
IMO	International Maritime Organization
IMC	Intermediate Metal Conduit
IMCS	Integrated Motor Control System
IMS	Information Management System
inst.	Instantaneous Quantity
INT	Interlock
int.	Intermittent Quantity
IP	Institute of Petroleum (UK) and its publications
IP	Ingress Protection Code (see IEC60529)
IPMSM	Interior Permanent Magnet Synchronous Motor
IR	Insulation Resistance
IS	Intrinsically Safe Signal, Circuit, or Equipment
Is/In, IS/IN	Ratio of Starting Current to Running Current
ISO	International Standards Organization
ISP	Internet Service Provider
ITU	International Telecommunication Union

J

Abbreviation	Full Form
-J	Energy in joules or newton-meters
J	Current density, amps/mm²
JB	Junction Box
JFET	Junction Field Effect Transistor
JEDEC	Joint Electron Device Engineering Council

K

Abbreviation	Full Form
-J	Energy in joules or newton-meters
J	Current density, amps/mm²
JB	Junction Box
JFET	Junction Field Effect Transistor
JEDEC	Joint Electron Device Engineering Council
kA	Kilo-amperes
KCL	Kirchhoff’s Current Law
KCMIL	Thousand Circular Mils
KEMA	Short circuit testing authority in The Netherlands
kg	Kilogram
km	Length in kilometers
kpm	Kilometers per hour
kV, Ku	Kilo-volts
kVA	Kilo-volt-amperes
kVAr	Reactive kilo-volt-amperes
KVL	Kirchhoff’s Voltage Law
kW	Kilowatts
KWH	Kilo Watt Hour

L

Abbreviation	Full Form
L	Electrical inductance in henries
L	Line (Phase, Live, or Hot) or local control operation
LA	Lightning Arrester
LAN	Local Area Network
lbs	Weight of a substance in pounds
LCD	Liquid-Crystal Display
LDB	Lighting Distribution Board
LDR	Light Dependent Resistor
LDS	Low Density Foam
LED	Light Emitting Diode
LEL	Lower Explosive Limit
LF	Low Frequency
LFMC	Liquid Tight Flexible Metal Conduit
LHS	Left-Hand Side
Li–ion	Lithium Ion (a type of rechargeable battery)
Lloyds	Lloyds Register of Shipping (UK)
LMS	Load Management System
LNA	Low Noise Amplifier
LNG	Liquefied Natural Gas
loc or (L)	Local Operation
LOP	Loss of Power
LOPT	Line Output Transformer
LOS	Loss of Signal
LPF	Low Pass Filter
LPG	Liquefied Petroleum Gas
LPS	Lightning Protection System
LRA	Locked Rotor Amperes
LSB	Least Significant Bit
LSDS, LSS	Load Shedding System
LSF	Low Smoke and Fumes (applied to cables and wires)
LSI	Large-Scale Integration
LSLH	Low Smoke Low Halogen
LSRS, LSR	Load Sharing System
LT	Low Tension
LTG	Lighting
LV	Low Voltage (50 to 600 volts)
LVDT	Linear Variable Differential Transformer
L1, L2, L3, N	Notation for line and neutral voltages and currents
LUT	Look-Up Table
LUX	Level of Illumination
LVDT	Linear Variable Differential Transformer

M

Abbreviation	Full Form
m	Length or dimension in meters, or month
mA	Current in milli-amperes
MAD	Mean Annual Discharge
man or (M)	Manual Operation
mbar	Milli-bar
MB	High-pressure mercury, without phosphor coating
MB	Megabyte, a computer data storage unit
MBB	Make-Before-Break
MBF	High-pressure mercury, with phosphor coating
MBFR	High-pressure mercury with phosphor coating and reflector
MBI	High-pressure discharge with metallic halides
MBIF	High-pressure discharge with metallic halides and phosphor coating
MBR	Double-ended linear arc tube
MBTF	Combination of MBF lamp and a filament lamp
MC	Metal Clad Cable
MCB	Miniature Circuit Breaker
MCC	Motor Control Center
MCCB	Moulded Case Circuit Breaker
MCM	Multi-Chip Module
MCP	Motor Circuit Protection
MCR	Maximum Continuous Rating
MCU	Motor Control Unit
MCu	Microcontroller
MDB	Main Distribution Board
MEC	Micro Energy Cell
MEMS	Micro ElectroMechanical Systems
MESFET	Metal-Semiconductor Field-Effect Transistor
MESG	Maximum Experimental Safe Gap
MF	Multiplying Factor
MFSK	Multiple Frequency-Shift Keying
Mho	Unit of Electrical Admittance
MI	Mineral Insulated
MIC	Minimum Ignition Current
MICC	Mineral Insulated Calendar Cable
MIDI	Musical Instrument Digital Interface
MIMIC	Mimic Display Panel
MISO	Master Input Slave Output
MLDB	Main Lighting Distribution Board
MLO	Main Lugs Only
mm	Length or dimension in millimeters
MMF, mmf	Magneto-Motive Force
MMI	Man–Machine Interface
MMSCF	Million Standard Cubic Feet of Gas
Mole %	Molecular Weight in %
MOSFET	Metal Oxide Semiconductor Field Effect Transistor
MOSI	Master Output Slave Input
MOV	Metal Oxide Varistor
MPCB	Motor Protection Circuit Breaker
MPDB	Main Power Distribution Board
MPPT	Maximum Power Point Tracking
MPU	Microprocessor
MS	Main Switch
MSB	Most Significant Bit
MSW	Module Steelwork
MT	Mica Glass Tape
MTBF	Mean Time Between Failures
MTTR	Mean Time to Repair
MUX	Multiplexer (several analog or digital inputs to single output)
MV	Medium Voltage
mV	Voltage in Millivolts
MVA	Mega-Volt-Amperes
MVAr	Reactive Mega-Volt-Amperes
MW	Megawatts

N

Abbreviation	Full Form
N or n	Number of items (e.g., generators installed)
N or n	Number of turns in a winding
N or n	Neutral terminal or line Neutral
NACE	National Association of Corrosion Engineers (USA)
NBR	Nitrile Butadiene Rubber
NC, N/C	Normally Closed switching device, No Connection
NCT	Neutral Current Transformer
NDE	Non-Drive End of a Shaft
NEC	National Electric Code (USA)
NEMA	National Electrical Manufacturer’s Association (USA)
NER	Neutral Earth Resistor
NFPA	National Fire Protection Association (USA)
Ni	Nickel Metal
NL	Neutral Link, Night Light
NO, N/O	Normally Open switching device
NOx	Nitrogen-Based Gas Emissions
NPR	Noise-Power Ratio
NPT	National Pipe Threads (USA)
NRZ	Non Return to Zero
NS	Used to describe a type of variable speed AC motor
NTC	Negative Temperature Coefficient
NTS	Not to Scale
NVM	Non-Volatile Memory

O

Abbreviation	Full Form
O	Open, off, or stop
OC, O/C	Overcurrent or Open Circuit
OCB	Oil Circuit Breaker
OCTC	On-Circuit Tap Changer
OCV	Open Circuit Voltage (difference in electrical potential when disconnected)
OF, O/F	Over Frequency
OFAF	Forced circulation of internal liquid, forced heat exchanging to external air
OFAN	Forced circulation of internal liquid, natural heat exchanging to external air
OHL, OHLine	Overhead Line
Ohms	Unit of electrical resistance or impedance
OIM	Offshore Installation Manager
OL, O/L	Overload
OLED	Organic Light-Emitting Diode
OLP	Overload Protection
OLR	Overload Relay
OLTC	On-Load Tap Changer
ONAF	Naturally circulated internal liquid, forced heat exchanging to external air
ONAN	Naturally circulated internal liquid, natural heat exchanging to external air
OpAmp	Operational Amplifier
OSC	Oscillator
OSHA	Occupational Health and Safety Administration (USA)
OTA	Operational Transconductance Amplifier
OV, O/V	Overvoltage
OVP	Overvoltage Protector

P

Abbreviation	Full Form
P or W	Active Power (Watts), Pole
p, s	Laplace Operator in mathematics (for transfer functions)
P & ID	Piping and Instrument Diagram
PA	Public Address System
PAL	Programmable Array Logic
PAM	Pulse or Pole Amplitude Modulation
PB	Push Button, Panic Button, or Pull Box
PB, Pb	Lead Metal
PBWB	Phosphor Bronze Wire Braid
PBCU, TCU	Tinned Copper
PC	Programmable Controller, Program Counter (used in microcontrollers)
PCB	Printed Circuit Board
PCC	Point of Common Connection, Power Control Centre
PCM	Pulse-Code Modulation
PDA	Personal Digital Assistant
PDB	Power Distribution Board
PDM	Pulse Density Modulation
PDP	Power Distribution Panel
PEC	PhotoElectric Cell
PELV	Protective Extra-Low Voltage (connected to earth at some point)
PF, pf	Power Factor
PFD	Phase/Frequency Detector
PFM	Pulse Frequency Modulation
PGA	Programmable Gain Amplifier
Ph, ph	Phases of an Electrical Circuit
PID	Proportional, Integral, Derivative (a type of controller used in control systems)
PIR	Passive Infrared Sensors
PIV	Peak Inverse Voltage
pk, peak	Peak Value of an Instantaneous Quantity
PLA	Programmable Logic Array
PLC	Programmable Logic Controller
PLCC	Plastic Leaded Chip Carrier
PLL	Phase-Locked Loop
PM	Permanent Magnet
PMIC	Power Management Integrated Circuit
pMOS	P-Channel Metal-Oxide Semiconductor
PMS	Power Management System
PMSM	Permanent Magnet Synchronous Motor
PNL	Panel
POL	Polyethylene, Point-of-Load
POR	Power-On Reset
Pot	Potentiometer
POV	Peak Operating Voltage
PPM	Pulse Position Modulation, Parts Per Million
PRC	Parasitic Resistance Cancellation
PRV	Peak Reverse Voltage
PSI	Pounds per Square Inch
PSK	Phase Shift Keying
PSR	Power-Supply Rejection
PSRR	Power Supply Rejection Ratio
PT	Potential Transformer
PTB	Physikalisch Technische Bundesanstalt
PTC	Positive Temperature Coefficient
PTP	Polyethylene Terephthalate
PTFE	Polytetrafluoroethylene
Pu, p.u.	Per Unit
PUT	Programmable Unijunction Transistor
PV	Photovoltaic
PVC	Polyvinyl Chloride
PVDF	Polyvinylidene Fluoride
PWD	Pulse-Width Distortion
PWM	Pulse Width Modulation
PWR	Power

Q

Abbreviation	Full Form
Q	Reactive Power, Volt-Amperes-Reactive, Charge
QA	Quality Assurance
QAM	Quadrature Amplitude Modulation
QC	Quality Control
QFP	Quad Flat Package
QTY	Quantity

R

Abbreviation	Full Form
R or r	Electrical Resistance
Rad, rad	Angular Displacement in Radians
RADAR	Radio Detection and Ranging
RAM	Random Access Memory
RCBO	Residual Current Circuit Breaker with Overload Protection
RCCB	Residual Current Circuit Breaker
RCD	Residual Current Device
RCU	Remote Control Unit
RDOL	Reverse Duty On Line Starter
Ref.	Reference
rem or (R)	Remote Operation
REQ	Required
RF	Radio Frequency (describing the rate of oscillation)
RFDS	Radio Frequency Design System
RFID	Radio Frequency Identification
RGB	Red Green Blue
RGS	Rigid Galvanized Steel Conduit
RHS	Right-Hand Side
RIO	Remote Input Output
RISC	Reduced Instruction Set Computer
RJ45	Registered Jack 45 (An 8-pin Ethernet Jack)
RLA	Rated Load Amperes
RLC	Resistance Inductance Capacitance
RMC	Rigid Metal Conduit
RMG	Ring Main Gear
RMS, rms	Root Mean Square
RMU	Ring Main Unit
RNC	Rigid Non-Metallic Conduit
ROM	Read Only Memory
RPR	Reverse Power Relay
RPS	Revolutions per Second
RPM	Revolutions per Minute
RSC	Rigid Steel Conduit
RTC	Real-Time Clock
RTD	Resistance Temperature Detector
RTOS	Real-Time Operating System
RTS	Remote Test Station
RTU	Remote Transmitter Unit, Roof Top Unit
Rx	Receiver
RYB	Red, Yellow, Blue (Old Color Codes used for Three-Phase Wiring – UK)

S

Abbreviation	Full Form
S	Apparent Power in Volt-Amperes
s or p	Laplace Operator in Mathematics, for Transfer Functions
S	Slip of a Rotating Machine with Respect to 1.0 pu
SAW	Surface Acoustic Wave
SB	Switch Board
SBM	Single Buoy Mooring
SC, S/C	Short Circuit
SCADA	Supervisory Control and Data Acquisition System
SCF	Standard Cubic Feet of a Gas
SCIM	Squirrel Cage Induction Motor
SCK	Serial Clock
SCR	Silicon Controlled Rectifier
SCS	Silicon Controller Switch
SCSI	Small Computer System Interface
SDR	Single Discipline Review
SEB	Service End Line Box or Service Electrical Box
SECT	Skin Effect Current Trace Heating
SELV	Safety Extra-Low Voltage
SFU	Switch Fuse Unit
SF6	Sulphur Hexafluoride
SI	System International of Units
SIM	Subscriber Identity Module
SIO	Serial Input and (Serial) Output
SIPO	Serial In Parallel Out
SLDB	Secondary Lighting Distribution Board
SLI	Double-Ended, Linear Arc Tube
SMD	Surface Mount Device
SMPS	Switch-Mode Power Supply
SMSB	Sub Main Switchboard
SMT	Surface Mount Technologies
SNR	Signal-to-Noise Ratio
SoC	System on a Chip
SOIC	Small Outline Integrated Circuit
SOLAS	Safety of Life at Sea, a Document Relating to Marine Practice
SON	Diffused Ellipsoidal Outer Bulb, Single-Ended Lamp
SONAR	SOund NAvigation and Ranging
SON-T	Clear Tubular Outer Bulb, Single-Ended Lamp
SON-TD, – L	Clear Tubular Outer Bulb, Double-Ended Lamp
SON-R	SON Lamp, with Internal Reflector
SOL CU	Solid Copper
SOP	Small Outline Package
SOT	Small Outline Transistor
SOX	U-Shaped Arc Tube, Single-Ended Lamp
Sox	Sulphur-Based Gas Emissions
SP	Single Phase
SPDT	Single Pole Double Throw
SPI	Serial Peripheral Interface
SPICE	Simulation Program with Integrated Circuit Emphasis
SPMSM	Surface Permanent Magnet Synchronous Motor
SPST	Single Pole Single Throw
SPT	Stranded Parallel Thermoplastic
sq	Square, e.g., sq mm is Square Millimeters
SR	Shift Register, Slew Rate
SRAM	Static Random Access Memory
SRF	Self-Resonant Frequency
SRIM	Slip Ring Induction Motor
SRM	Switched Reluctance Motor
SSB	Single SideBand
SSI	Small Scale Integration
SSR	Solid State Relay, Synchronization Check Protection Relay
ST	Super Tension, Shunt Trip
STA	Steel Tape Armoure
STG	Steam Turbine Generator
STP	Shielded Twisted Pair
STR	Statimax Trip Release
STR CU	Stranded Copper
SW	Switch, Shortwave (e.g., in Shortwave Bands)
SWA	Steel Wire Armour
SWBD	Switchboard
SWG	Standard Wire Gauge
SWGR	Switchgear
SYNC, Sync	Synchronizing
SYM	Symmetrical
SyRM	Synchronous Reluctance Motor

T

Abbreviation	Full Form
T or t	Time, usually in seconds
TB	Terminal Block
Td	Time Constant in Seconds for the Quantity ‘d’
TC	Temperature Coefficient
TCP/IP	Transmission Control Protocol/Internet Protocol
TDRM	Time Delayed Restart Relay
TEFC	Totally Enclosed Fan Cooled
TEL	Telephone
TEM	Transverse Electromagnetic (Wave)
temp.	Temperature
TESFC	Totally Enclosed Separate Fan Cooled, Fan Attached to an Auxiliary Motor Shaft
TF	Transfer Function
T/F	Transformer
TFD	Thin Film Detector
TFT	Thin Film Transistor
TG	Turbo-Generator, Gas or Steam
TGB	Telecommunications Grounding Bus Bar
THD	Total Harmonic Distortion
THF	Telephone Harmonic Factor
TOP	Gas-Turbine Operating Temperature (Hot-End Blade Temperature)
TM	Technical Measurement System of Units
TMCB	Thermal Magnetic Circuit Breaker
TCP	Gas-Turbine Control Panel
TLX	Cold Starting Tubular Fluorescent Lamp, with Single-Pin Caps
TPDT	Triple Pole Double Throw
TPIC	Triple Pole Iron Clad
TPN	Three-Phase and Neutral Power Supply
TPPL	Total Plant Peak Load
TPRL	Total Plant Running Load
TPS	Triple Pole Switch
TPST	Triple Pole Single Throw
Tran., Tx	Transformer
TRS	Tough Rubber Sheathed
TTL	Transistor-Transistor Logic
TVS-Diode	Transient Voltage Suppression Diode
Tx	Transmitter

U

Abbreviation	Full Form
U	Voltage, also used for energy
UART	Universal Asynchronous Receiver and Transmitter
UC, U/C	Undercurrent
UCP	Unit Control Panel
UDS	Uniform Drawing System
UEL	Upper Explosive Limit
UF, U/F	Under Frequency
UG	Under Ground
UHF	Ultra High Frequency
UI, U/I	Undercurrent
UJT	Unijunction Transistor
UL, U/L	Under Load
UL	Underwriters Laboratory (USA)
UVLO	Under Voltage Lockout
UNO	Unless Noted Otherwise
UPS	Uninterruptible Power Supply Unit
USART	Universal Synchronous and Asynchronous Receiver and Transmitter
USB	Universal Serial Bus
UTP	Unshielded Twisted Pair
UV, U/V	Under Voltage

V

Abbreviation	Full Form
V, U	Voltage or Volts
VA	Volt-amperes
VAC, Vac	Alternating Voltage
VAr, Var	Reactive Volt-amperes
VCA	Voltage Controlled Amplifier
VCB	Vacuum Circuit Breaker
VCC	Voltage at the Common Collector
VCCS	Voltage Controlled Current Source
VCD	Variable Capacitance Diode
VCO	Voltage Controlled Oscillator
VCXO	Voltage-Controlled Crystal Oscillator
VDC, Vdc	Direct Voltage
VDE	Verband Deutscher Electrechniker (Germany)
VDI	Verein Deutscher Ingenieure (Germany)
VDU	Visual Display Unit
VFD	Variable Frequency Drive, Vacuum Fluorescent Display
VFDP	Variable Frequency Drive Panel
VFO	Variable-Frequency Oscillator
VGA	Video Graphics Adapter
VHF	Very High Frequency
VIR	Vulcanized Indian Rubber
VLSI	Very Large Scale Integration
VOM	Volt Ohm Meter, a device also known as a Millimeter or Multitester
VSD, VSDS	Variable Speed Drive Systems
VSI	Voltage Source Inverter
VSWR	Voltage Standing Wave Ratio
V.T., VT	Voltage Transformer
v/v	Comparison by volume, per-unit
VVVF	Variable Voltage Variable Frequency Drive

W

Abbreviation	Full Form
W or P	Active power, watts
w or ω	Frequency in radians per second
wdg.	Winding of a machine or transformer
WH	Water Heater
WHRU	Waste Heat Recovery Unit
WLAN	Wireless Local Area Network
WP	Weather Proof
WRIM	Wound Rotor Induction Motor
WRSM	Wound Rotor Synchronous Motor
WSN	Wireless Sensor Network

X

Abbreviation	Full Form
X	Electrical reactance
XFMR	Transformer
XLPA	Cross-linked polyalkene
XLPE	Cross-linked polyethylene
XO	Crystal Oscillator

Y

Abbreviation	Full Form
Y	Electrical admittance (Also used for Star Connection)
y	Year

Z

Abbreviation	Full Form
Z	Electrical impedance
ZH	Zero halogen, as used for cables
ZVC	Zero voltage crossing
ZVS	Zero voltage switching

Numerical Abbreviations

Abbreviation	Full Form
1P, SP	Single phase
3P	Three-phase supply
3P-N	Three-phase and neutral supply
3P-N-E	Three-phase neutral and earth supply
2W	Two-wire supply
3W	Three-wire supply
4W	Four-wire supply
3G	Third Generation
3R3	3.3 ohm Resistor
4K	4,000 pixels
4P4T	Quad-Pole Quad-Throw
4WJ	Four-Way Junction