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

HSW1S91

IEC

Phase-to-neutral voltmeter selector

This representation identifies selection among phase-to-neutral voltage measurement connections. The meter is connected to the selected phase relative to the documented neutral or reference point. That connection differs from measuring between two phase conductors.

Drawing use: Schematic
Application: Metering & protection
Reference family: IEC / Manufacturer
Form evidence: Phase-to-neutral voltmeter selector. Autodesk IEC-60617 Symbol Preview — Measurement-selection and mechanically operated switch forms; vendor family reference, not certified IEC geometry or database identifier.

A distinction that matters

Phase-to-neutral and phase-to-phase measurements have different connection paths.

Full reference

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 reference

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