Understand the difference.

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

STSB

Symbols

Single-pole trip selection block

Routes the assigned fault decision to its identified phase operating output. A protection scheme combines measurements, decision elements and communication or trip outputs to protect a defined part of the network. A function number names a job; the scheme interface shows how that job connects to other equipment.

Drawing use

Schematic

Application

Metering & protection

Reference family

Manufacturer

A distinction that matters

The breaker must support the operating arrangement. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

Full referenceAdd to legend

TTCB

Symbols

Three-pole trip conversion block

Converts the defined protection condition into an assigned three-pole opening request. A protection scheme combines measurements, decision elements and communication or trip outputs to protect a defined part of the network. A function number names a job; the scheme interface shows how that job connects to other equipment.

Drawing use

Schematic

Application

Metering & protection

Reference family

Manufacturer

A distinction that matters

Conversion criteria depend on the approved scheme. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

Full referenceAdd to legend

Follow the full entry for source drawings and the appropriate standard or selected product. Equipment previews show a manufacturer drawing where available, otherwise a 3D thumbnail.