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

Symbols

Potential test switch

A potential test switch is a knife switch in a VT secondary circuit that isolates a relay or meter from the VT so test voltages can be injected. Unlike a current switch it has no shorting contact, because a VT secondary must never be shorted.

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

A distinction that matters

A potential test switch opens a voltage circuit; a current test switch shorts the CT before opening.

Full reference

Symbols

Current test switch with shorting contact

Panel-mounted test switches used in North American practice often combine a knife switch with a shorting contact for each CT circuit. Opening the switch first shorts the CT secondary and then isolates the relay or meter, so a test set can be connected without exposing the CT to an open circuit.

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

A distinction that matters

A current test switch shorts the CT on opening; a potential test switch simply opens the voltage circuit.

Full reference

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