Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

CT

Symbols

Wound-primary current transformer

A wound-primary CT has a primary winding of more than one turn rather than a single bar or conductor through a window. This is needed at low primary currents, where a single turn would not produce enough magnetising ampere-turns for accurate metering, and it is common in MV metering units.

Drawing use

SLD / Schematic

Application

Metering & protection

Reference family

IEC / Manufacturer

A distinction that matters

A wound-primary CT has a multi-turn primary; a window or bar CT uses the circuit conductor as a single-turn primary.

Full referenceAdd to legend

CT

Symbols

Current transformer

A current transformer produces a secondary current related to the current in its primary conductor. A drawing uses the CT representation to show where current is measured and which metering or protection circuit receives that measurement. It does not, by itself, specify the CT ratio, accuracy class, burden or secondary connection.

Drawing use

SLD / Schematic

Application

Metering & protection

Reference family

IEC / IEEE / ANSI

A distinction that matters

A CT measures current. A VT measures voltage. Their secondary circuits and isolation/testing arrangements are different.

Full referenceAdd to legend

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