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

IEC

Water heater plan mark

Electric water heaters are drawn as a circle or rounded tank outline with a heating mark and the letters WH or HWU. The symbol locates the unit and its connection, often with an isolator alongside.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Water heater. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A space heater warms air; a water heater warms stored water and is often on a controlled tariff.

Full reference

HTR

IEC

Electric space heater plan mark

Fixed space heaters such as panel heaters, convector heaters and radiant wall heaters are drawn as a rectangle at the wall with parallel strokes or a zigzag representing the heating element. The rating in watts or kilowatts is usually written beside the symbol.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Space heater. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A heating element in a schematic is a component; this plan mark represents an installed heater appliance.

Full reference

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