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 LOCK

Symbols

Lockable switch-disconnector

A lockable switch-disconnector combines an isolation-capable switching device with a documented locking provision. It appears in feeder isolation and maintenance arrangements where both the electrical and mechanical functions matter.

Drawing use

SLD / Schematic

Application

Power distribution

Reference family

IEC / Manufacturer

A distinction that matters

A locking handle does not increase the switching or fault-interruption rating.

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.