I don't do many wiring diagrams and when I do them are super basic. I have used Open Office Draw. Libre Office has a similar product.
Right now I am using Lucid chart. I mostly do network/equipment diagrams and Lucid chart is pretty cool because it you can import Viso stencils that manufacturers provide. They also have a lot of common icons available without importing icons. They have a Cisco, wiring, process engineering, flowchart, floorplan, rack, and more sets. It is $5 a month paid yearly for a single user. I find it easier to use than Draw, but maybe it's just because I have had more practice.