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

Relay test block

A relay test block sits in the secondary wiring between CTs, VTs, trip outputs and a protection relay. Inserting a test plug or opening the block isolates the relay from the plant, automatically shorts CT circuits before they are opened and isolates trip outputs, so the relay can be tested with secondary injection while the primary circuit stays in service.

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

A distinction that matters

A relay test block isolates and shorts circuits in one operation; a single CT test terminal handles only one conductor.

Full reference

CT test

Symbols

CT test terminal

A CT test-terminal arrangement connects current-transformer secondary wiring to measurement or protection equipment and provides the test or short-circuit facilities specified for the selected assembly. Its representation must be read with the manufacturer circuit and operating documentation.

Drawing use: Schematic
Application: Connections & wiring
Reference family: IEC / IEEE / ANSI

A distinction that matters

A generic disconnect terminal is not automatically suitable for a CT secondary circuit. Use an arrangement specified for the CT application.

Full reference

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