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

IEEE / ANSI

ANSI/IEEE lockable switch-disconnector symbol

The lockable switch-disconnector form combines load switching, isolation and a documented locking provision. These are separate capabilities recorded against the same device, rather than inferred from a single contact gap or padlock outline.

Drawing use

SLD / Schematic

Application

Power distribution

Reference family

IEEE / ANSI / Manufacturer

Form evidence

Autodesk IEEE-oriented Disconnect 1 Pole 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

Adding a locking modifier to a switch does not prove that it has the isolation function of a switch-disconnector.

Full referenceAdd to legend

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

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