Q020501
Unidirectional propagation qualifier
This qualifier indicates a signal or propagation path with one documented direction.
IEC
Electrical symbols.
Explore electrical symbols, functional blocks and circuit arrangements for switchgear, switchrooms, substations, switchyards and microgrids. Detailed explanations, drawing notes, public sources and original SVG/DXF illustrations.
Installation & communications
Q020502
Simultaneous bidirectional propagation qualifier
This qualifier distinguishes a path supporting propagation in both directions at the same time.
IEC
Q020503
Alternating bidirectional propagation qualifier
This qualifier identifies opposite-direction propagation occurring alternately.
IEC
Q020504
Signal-transmission qualifier
A transmission qualifier identifies the sending role of a signal interface.
IEC
Q020505
Signal-reception qualifier
A reception qualifier identifies the receiving role of a signal interface.
IEC
Q020901
Non-ionising radiation qualifier
This qualifier identifies the publisher's non-ionising radiation family, with the radiation role stated in the device description.
IEC
HAN1B7
Loudspeaker annunciation
A loudspeaker indication identifies conversion of an electrical signal to an audible output.
IEC
HAN1B8
Combined loudspeaker and microphone
This representation identifies an electroacoustic device serving loudspeaker and microphone roles.
IEC
HAN1B9
Microphone input
A microphone indication identifies an acoustic-input transducer in a communications circuit.
IEC
HCN1RSGL
Single power receptacle
This form identifies a single power receptacle connection in the publisher's installation family.
IEC
HCN1RDUP
Duplex power receptacle
This form distinguishes a duplex receptacle arrangement.
IEC
HC01WR_1-
One-line power receptacle
A one-line receptacle represents a power outlet within a simplified circuit view.
IEC
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Read the drawing, not just the mark
Small details. Different meanings.
Understand symbols, equipment tags and function numbers—and know when a generic object needs a manufacturer drawing.
In plain English
What do electrical symbols tell you?
Electrical symbols are shorthand for equipment, functions and connections. They let you follow how a circuit works without drawing every physical detail.
A simple example
On a microgrid single-line diagram, a current-transformer symbol marks a measurement point and a breaker symbol marks where a circuit can be disconnected. Their labels identify the actual equipment.
What the drawings help you do
Follow the connected lines to trace power or control signals. Use the project legend to interpret symbols and the selected manufacturer's drawings for dimensions and terminal connections.
- Single-line diagram
- A simplified power-system drawing that often uses one line to represent a three-phase circuit.
- Legend
- The key explaining a drawing's symbols and labels.