Edit Electrical plans

You could give Illustrator a try on the free 7-day trial to see if works for what you want to do.

You may be able to edit the graphical content, i.e. lines, annotations and so on, but in doing so will likely invalidate the compliance with technical norms like DIN/ VDE here in Germany or their regional equivalents. So if it's for serious documentation purposes I would be extremely cautious. It's of course okay for your own little fun projects, though it's going to be like pulling teeth. Even the simplest electrical CAD programs will easily beat AI.

Mylenium

There might be issues importing PDFs as PDFs were never meant for editing.

You will need to try if Illustrator can fully read them.

Webster,

You can create/edit (certain versions of) things like those using AI.

But for editing, it rather depends on the application used to create the original to edit, and the exact appearance/strutcure.

Electrical plans can mean quite different things.

So a bit more to start on would help helpers help you.