HTR
Electric space heater plan mark
Plan mark for a fixed electric space heater, drawn as a rectangle with internal heating strokes.
IEC
IEC · WH
Water heater plan mark
Plan mark for an electric water heater or hot-water storage unit with its electrical connection point.
In plain English
What does Water heater plan mark mean?
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.
A simple example
Water heaters may be on a controlled or off-peak tariff circuit, so the plan symbol is frequently tagged with the tariff or a time-switch link. The installer must route the circuit to the correct part of the board or meter. The symbol does not give capacity or element rating. These are scheduled with the plumbing equipment.
What the drawings help you do
Check tariff or control circuit notes. Locate the isolator. A space heater warms air; a water heater warms stored water and is often on a controlled tariff.
This particular reference
Plan mark for an electric water heater or hot-water storage unit with its electrical connection point. A space heater warms air; a water heater warms stored water and is often on a controlled tariff.
- Terminal
- An identified point where a conductor connects.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: IEC graphical symbols for diagrams
IEC · Water heater
IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
GA · WH
What it represents
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.
Water heaters may be on a controlled or off-peak tariff circuit, so the plan symbol is frequently tagged with the tariff or a time-switch link. The installer must route the circuit to the correct part of the board or meter. The symbol does not give capacity or element rating. These are scheduled with the plumbing equipment.
How to read it
- Check tariff or control circuit notes.
- Locate the isolator.
Information to show or reference
- State element rating.
- State tariff or control arrangement.
- Show isolator.
A distinction that matters
A space heater warms air; a water heater warms stored water and is often on a controlled tariff.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
IEC graphical symbols for diagrams
IEC graphical symbol context; independently drawn here.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
Explore related references
Put the reference into a drawing workflow.
Elora Grid helps electrical teams work with drawings, specifications and equipment information. Explore the drafting workflow or join the early-access waitlist.