Switching Programs Terminology & Abbreviations

Before starting to write a switching program, it is important to understand and use standard terminology. The table below includes some common fields found on templates.


Program Field Meaning
Program number This is obtained from the operating authority
Written By An operator who is authorised to carry out the operations within the program
Checked By An operator same as above
Dates The date the program was written and the date it was checked
Copies To List of persons or places to receive copies of the program
Item This is a sequential list of numbers for each operation to be carried out
Location – Instructions Refers to the location of the equipment to be operated and any special instruction required
Plant Names the plant to be operated
Operation Describe the operation to be carried out on the named plant
Time Precise time operation was carried out
Voltage Highest voltage that operations will be carried out at
Sheet Number Sheets are to be numbered; e.g. 1 of 3, 2 of 3, 3 of 3
Substation Refers to any substations where circuits are affected by the program
Circuit Name of the circuit that operations are being carried out upon
Section to be Isolated A brief description of the section
Work to be Carried Out Briefly describe the purpose of the program
Operator in Charge Is the authorised operator who will carry out the program, or the operator who will control other operations on the program

Only standard accepted terms should be used on the program. Below is a table of standard terminology used when developing switching programs.

Term Action Required
AUTO Switch a control to an automatic position
BOTTOM BUS The busbar at the bottom of metal clad switchgear
BUS COUPLER A switching device that connects two different busbars together
BUS TIE A switching device that connects sections of the same busbar together
CABLE An underground cable.
COMPOUND Ground mounted transformer
D/L Fitting of danger label to equipment to warn against operation.
EARTH. Placement of portable earths or closing an earth switch to ON.
FRONT BUS The busbar closest to the front of metal clad switchgear.
ISOLATED To disconnecting equipment from all sources of supply.
MANUAL Switch a control to  a manual position
MANUAL FIX TAPS Switching the control of automatic tap changes to manual and   alteration of taps for equalisation of volts.
OFF Where a switch is put in the position or condition where contacts are open and current cannot flow.
ON When a switch is in a position where contacts are closed & current can pass through.
PADMOUNT A pad mount type substation or kiosk
R D/L Removal of a danger label
RACK DOWN The physical disconnection of a metal clad OCB or ACB from the busbar.
RACK UP The physical connection of a metal clad OCB or ACB to the busbar
REAR BUS The busbar furthest from the front of metal clad switchgear
REMOVE EARTH Portable earths removed from equipment
TOP BUS The busbar at the top of metal clad switchgear.

You also need to be aware of common abbreviations used on switching programs. It is critical that all personnel involved with the program understand the abbreviations correctly.

Abbreviation Description
A/R Auto Reclose
ABS Air Break Switch
ACB Air Circuit Breaker
CL Caution Label (Vicinity Work in Progress)
CT Current Transformer
DL Danger Label
DOF Drop Out Fuse
E/SW or E/S Earthing Switch
EAP Electrical Access Permit
GCB Gas Circuit Breaker
GMTX or PMT Ground Mounted Transformer or Padmount Transformer
HV High Voltage
ISOL Isolator
K/SW Knife Switch
LA Lightning Arrestor
LDC Line Drop Compensator
LV Low Voltage
MS Main Switch
OCB Oil Circuit Breaker
OLTC On Load Tap Changer
OSF Oil Switch Fuse
PMTX or PTT Pole Mounted Transformer
PTS Pole Top Switch
R/IN Rack In
R/OUT Rack Out
RCL Remove Caution Label
RD Rack Down
RDL Remove Danger Label
REC Recloser
RIC Recipient in Charge
RM/ES Ring Main Earth Switch
RM/IS Ring Main Isolator
RMU Ring Main Unit
RU Rack Up
SMTX Skid Mounted Transformer
STT Sanction to Test
SW Switch
TX Transformer
VA Vicinity Authority
VCB Vacuum Circuit Breaker
VT Voltage Transformer


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