Electrical Symbols

Location Symbols for Installations

	Machine, general symbol * function etc
	Load, general symbol * details
	Motor starter, general symbol * Indicates type etc.
	Socket-outlet, general symbol
	Twin Socket-outlet, general symbol
	Switched socket-outlet
	Twin Switched socket-outlet
	Switch, general symbol
	2 way switch, single pole
	Intermediate switch
	Pull switch, single-pole
	Push button
	Clock, general symbol
	Bell (Audible)
	Buzzer (Audible)
	Siren (Audible)
	Horn
	Telephone handset, general symbol

Popular Symbols

Making and breaking current

	Switch
	Switch- fuse
	Fuse-switch

Isolating

	Isolator (Disconnector), general symbol
	Disconnector - fuse (fuse combination unit)
	Fuse - disconnector

Making, breaking and isolating

	Switch - disconnector
	Switch - disconnector - fuse (fuse combination unit)
	Fuse - switch - disconnector
	Capacitor, general symbol
	Inductor, coil, winding or choke
	Inductor, coil, winding or choke with magnetic core
	Semi Conductor Diode - general symbol
	Microphone
	Loudspeaker
	Antenna, general symbol
	Machine, general symbol * Function M=Motor G=Generator
	Generator, general symbol
	Indicating instrument, general symbol * function V = Voltmeter A = Ammeter etc.
	Integrating instrument or Energy meter * function Wh = Watt-hour VArh = Volt ampere reactive hour
	Lamp, or signal lamp, general symbol

Lamps & Lighting

The following table provides the commonly used electrical wiring schematic symbols for push-buttons and lamps which comply with the IEC and BS Electrical Symbols. We have included the Normally Open and Normally Closed status for each contact.

	Lamp (Standard)
	Lamp Standard
	Filament Lamp
	Lamp (Flashing)
	Lighting outlet position - general symbol
	Fluorescent luminaire
	Wall mounted luminaire
	Self - contained emergency lighting luminaire
	Emergency lighting luminaire (or special circuit)
	Light Emitting Diode (LED)

Connectors and Earthing

The following table provides the commonly used electrical wiring schematic symbols for connectors which comply with the IEC and BS Electrical Symbols. These connectors include plug and socket, coaxial, terminal and earth connectors.

	Plug Male		Socket (plug female)
	Coax Plug Male		Slow Operating Relay - Delay On
	Wire Connections (Two Wires)		Wire Connections (crossed)
	Wires Crossing (Not Connected)		Terminal Connector
	Terminal Block		Earth Connection
	Noiseless Earth		Protective Earth
	Chassis Earth		Equipotentiality

General Symbols

	Ammeter		Voltmeter
	Circuit Breaker		Selector Switch (N/O) Normally Open (N/C) Normally Closed
	Contactor (N/C)		Contactor (N/O)
	Limit Switch		Thermal Overcurrent
	Mechanical Interlock		Voltage Transformer
	Potentiometer		Solenoid Valve

Contacts and Switches

The following table provides the IEC and BS Electrical Symbols for contacts. We have included the Normally Open and Normally Closed status for each contact

	Normally open Contact (N/O)		Normally Closed Contact (N/C)
	Change Over or 2 way Contact Made position		Fused Switch Open Contact (N/O)
	Limit Switch (N/O)		Limit Switch (N/C)
	Flow Switch (N/O)		Flow Switch (N/C)
	Time Delay (N/O) Delay on Closing		Time Delay (N/O) Delay on re-opening
	Thermal Switch - Overload (N/O)		Thermal Switch - Overload (N/C)
	Temperature Switch (N/O)		Temperature Switch (N/C)
	Pressure Switch (N/O)		Pressure Switch (N/C)

Push-buttons

The following table provides the commonly used electrical wiring schematic symbols for push-buttons and lamps which comply with the IEC and BS Electrical Symbols. We have included the Normally Open and Normally Closed status for each contact.

	Normally Open PB (N/O)
	Normally Closed PB (N/C)
	Emergency Stop PB (N/O) Indication Contact
	Emergency Stop PB (N/C)
	Pull Switch (N/O)
	Pull Switch (N/C)
	Turn/Rotary Switch (N/O)
	Turn/Rotary Switch (N/C)

Coils and Relays

Electrical Symbols - Coils and Relays
The following table provides the commonly used electrical wiring schematic symbols for coils and relays which comply with the IEC and BS Electrical Symbols
	Contractor Coil
	Relay with AC Supply
	Slow Release Relay Delay Off
	General Relay (DC Supply)
	Slow Operating Relay Delay On
	Mechanically Latched Relay

Semi Conductors

The following table provides the commonly used electrical wiring schematic symbols for coils and relays which comply with the IEC and BS Electrical Symbols

	Contractor Coil
	Relay with AC Supply
	Slow Release Relay Delay Off
	General Relay (DC Supply)
	Slow Operating Relay Delay On
	Mechanically Latched Relay

Other Symbols

	Three-phase winding - Star
	Changer, general symbol Converter, general symbol Notes: (1) If the direction of change is not obvious, it may be indicated by an arrowhead on the outline of the symbol. (2) A symbol or legend indicating the input or output quantity, waveform etc. may be inserted in each half of the general symbol to show the nature of change.
	Rectifier
	Inverter
	Primary cell - longer line positive, shorter line negative
	Battery
	Fuse link, rated current in amperes