Side-by-side reference

Understand the difference.

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

First referenceCompare with

Protection functions

Unit sequence starting relay

Starts the next unit or operating step when the documented sequence condition is met.

Drawing use: SLD / Schematic
Application: Metering & protection
Reference family: IEEE / ANSI

A distinction that matters

A unit sequence starting relay advances a defined sequence; it does not identify the entire master sequencer.

Full reference

Protection functions

AC circuit breaker

Device function number 52 identifies an AC circuit breaker in the power-system device-function convention. It can appear in equipment identification, control references or a protection drawing, but it remains distinct from the graphical symbol and product specification.

Drawing use: SLD / Schematic
Application: Power distribution
Reference family: IEEE / ANSI

A distinction that matters

The number 52 identifies a device function. It is not an IEC graphical-symbol identifier, breaker current rating or manufacturer model.

Full reference

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