Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

PB NC

IEEE / ANSI

ANSI/IEEE normally closed pushbutton symbol

The momentary NC pushbutton form describes a normally continuous path opened by the operator. Its circuit role can be stop, inhibit or another command, but that purpose comes from the wiring and label rather than from NC alone.

Drawing use

Schematic

Application

Control circuits

Reference family

IEEE / ANSI / Manufacturer

Form evidence

Autodesk IEEE-oriented Push Buttons functional form. Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.

A distinction that matters

An NC contact form does not by itself identify a complete emergency-stop safety circuit.

Full referenceAdd to legend

PB NC

Symbols

Normally closed pushbutton

A normally closed pushbutton has a contact closed in its specified normal state. Actuation changes that contact state according to the selected operator and contact block. Momentary, maintained, latching and positive-opening characteristics must be identified from device documentation.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / IEEE / ANSI

A distinction that matters

An ordinary NC pushbutton and an emergency-stop device are not interchangeable solely because both drawings show a closed contact.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.