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

Test plug

A test plug fits into a test block or test switch and brings each pole out to test leads. Depending on its design it can connect test equipment to the relay side only, or link plant and relay sides through an ammeter for in-service current measurement.

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

A distinction that matters

A test plug is the removable part; the test block or switch is the fixed part wired into the circuit.

Full reference

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

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