In the Q&A Request Support for CircuitLab schematic editor, I disagreed with the proposal to use CircuitLab for creating wiring diagrams.
But that raises the question if there is an app that would be better suited for that purpose. I don't know of any so wanted to crowd-source the question.
Some requirements that I thought of (there may be more, please comment if you think of any):
- Online, can be embedded in a post on DIY.SE.
- Stores the diagram state within the post so that it can be saved and edited, or copied from a question into an answer.
- Provides conventional symbols for home wiring diagrams.
- Reasonable cost (I don't know how much it costs SE to use CircuitLab, but presumably the cheaper it is the more likely they'd approve it).
- Bonus: can also be used for other types of diagrams: floorplans, plumbing, gas, etc.