Understand the difference.

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

SD

Symbols

Switch-disconnector

A switch-disconnector combines operational switching with an isolation function. Its designation should distinguish it from a disconnector that is not intended to interrupt load current.

Drawing use

SLD / Schematic

Application

Power distribution

Reference family

IEC / Manufacturer

A distinction that matters

A load-break switch is not automatically a switch-disconnector; isolation suitability must be documented.

Full referenceAdd to legend

Isolator

Symbols

Disconnector

A disconnector, often called an isolator, provides an isolation function in an electrical circuit. Its representation should be read with the drawing legend and the selected device specification. Do not infer load-breaking or fault-interruption capability simply because a drawing contains a switch-like mark.

Drawing use

SLD / Schematic

Application

Power distribution

Reference family

IEC / IEEE / ANSI

A distinction that matters

A load-break switch has a specified load-switching capability. A disconnector designation alone does not establish that capability.

Full referenceAdd to legend

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