Electrical Basic Abbreviations and Full FormsSl.No. Abbreviation Explanation 1 HT High Tension (Transformer HT side) 2 LT Low Tension 3 AB switch Air Break switch 4 DO fuse Drop Out fuse 5 ACB Air Circuit Breaker 6 VCB Vacuum Circuit Breaker 7 SF6 Circuit Breaker Sulphur Hexafluoride Circuit Breaker 8 ACDB Alternating Current Distribution Board 9 DCDB Direct Current Distribution Board 10 PDB Power Distribution Board 11 MPDB Main Power Distribution Board 12 PCC Power Control Centre 13 MCC Motor Control Centre 14 MCP Motor Control Panel 15 VVVF Variable Voltage Variable Frequency Drive 16 VSD Variable Speed Drive 17 DOL Direct On Line 18 RDOL Reverse Duty On Line 19 MLDB Main Lighting Distribution Board 20 SLDB Secondary Lighting Distribution Board 21 EMLDB Emergency Lighting Distribution Board 22 CPSS Construction Power Substation 23 DSS Distribution Power Substation 24 RCC Remote Control Cables 25 MCB Miniature Circuit Breaker 26 MCCB Moulded Case Circuit Breaker 27 MPCB Motor Protection Circuit Breaker 28 EMPR Electronic Motor Protection Relay 29 RCCB Residual Current Circuit Breaker 30 RCBO Residual Current Circuit Breaker with Over-current Protection 31 ELCB Earth Leakage Circuit Breaker 32 HRC fuse High Rupture Capacity fuse 33 OLTC On Load Tap Changer 34 FCMA Flux Compensated Magnetic Amplifier 35 UPS Un-interrupted Power Supply 36 SMF Battery Sealed Maintenance Free Battery 37 JB Junction Box 38 PB Push Button 39 TB Terminal Box 40 LCB Local Control Board 41 LCS Local Control Station 42 SPNDB Short circuit Protection Neutral Distribution Board 43 TPNDB Three Phase and Neutral Distribution Board 44 CT Current Transformer 45 PT Potential Transformer 46 SCIM Squirrel Cage Induction Motor . 47 ACVS Air Conditioning and Ventilation System 48 FDA Fire Detection and Alarm 49 PCS Pull Cord Switch 50 ZSS Zero Speed Switch 51 BSS Belt Sway Switch 52 NO Normally Opened 53 NC Normally Closed 54 TEFC Total Enclosed Fan Cooled 55 TESC Totally Enclosed Surface Cooled 56 ISMC Indian Standard Medium weight Channel 57 GI busbar Galvanized Iron bus bar (for Earthing) . Abbreviation Explanation 1 PLC Programmable Logic Controller 2 DCS Distributed Control System 3 MPI Multi Point Interface 4 DP Distributed Peripheral 5 SCADA Supervisory Control And Data Acquisition 6 HART Highway Addressable Remote Transducer 7 HMI Human Machine Interface 8 MMI Man Machine Interface 9 VDU Visual Display Unit 10 RIO Remote Input Output 11 TCP/IP Transmission Control Protocol-Internet Protocol 12 CFC Continuous Function Chart 13 SFC Sequential Function Chart 14 PID control Proportional Integral and Derivative control 15 RAM Random Access Memory 16 ROM Read Only Memory 17 PROM Programmable Read Only Memory 18 EPROM Erasable Programmable Read Only Memory 19 EEPROM Electrically Erasable Programmable Read Only Memory 20 RTD Resistance Temperature Device .Automation and Instrumentation Sl.No. Standards Sl. Abbreviation Explanation 1 IEC International Electrotechnical Commission 2 EN European Norms 3 CENELEC European Committee for Electrotechnical Standardization 4 VDE Verband Deutscher Elektrotechniker 5 BS British Standards 6 ISA International Standards Association 7 ISO International Standards Organization 8 NEMA National Electrical Manufacturers Association 9 BIS Bureau of Indian Standards 10 IEEE Institute of Electrical and Electronics Engineers 11 ISI Indian Standards Institute 12 ANSI American National Standards Institute 13 IP Ingress Protection 14 ISMC International Society of Motor Control .No.