Most of mine start with a drawing from somewhere and modify it with paint. I have so many now I often have one to match the need.I want to know where all these DIY guys get the software to draw such nice diagrams.
After pasting into paint you can save in many different formats including jpg or png. You can also resize to make if fit the screen better or get below the size limit.I try that, but it copies in an incorrect format, not JPG or PNG. I can't recall, but it doesn't let you post it after it is modified.
Called heatex. Made for 240 loads like water heaters.Just want to point out that the OP is from Canada where they have 240 nm cables--- Black and Red w/ ground. This does not change what you are saying and I only mentioned it so others will know that the cabling in Canada is different. I wish they would do that here in the USA.