PB NO
Normally open pushbutton
A pushbutton contact normally shown open before actuation.
Schematic
Symbols · KEY NC
Key-operated normally-closed switch
A key-operated NC switch opens its reference closed contact through the key mechanism.
Schematic · KEY NC
What it represents
A key-operated NC switch opens its reference closed contact through the key mechanism. Its access and switching functions must be documented separately.
How to read it
- Read the reference position from the operator schedule.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.
Information to show or reference
- Define normal key position
- State contact action
- Reference key-removal restrictions
A distinction that matters
NC identifies the contact reference state, not a guarantee of tamper-proof control.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
AutoCAD Electrical: Level, flow, keyed and measurement switches
Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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