I am going to put some more wiring into some empty house (mostly CAT6 and audio) and want them to be in the walls. For that I borrowed some saw that can cut nice slits for them into the wall, but of course there is already some wiring in it.
Since the house is old (First built 19th century, burned down, restored, bombed out, restored etc.) the existing wiring can be quite funny sometimes (curves in weird ways, straight from top left to bottom right etc.) and I do not want to cut through it.
I have found a system that lets me detect if a spot has live wires quite nicely (and ignores non live wires) but for the amount of cable I am going to run, this would make the planning quite cumbersome: Think about where to put cables, check that way, find existing wiring, find detours, check those again etc.
Ideally I would want to paint at the walls where the wires are (and then take photos for later references) and then plan where to put the wires based on that.
Does anyone have an idea how to create such a map rather efficiently? Checking a matrix of points every few cm is going to take too long, and tracing from the beginning of known switches/outlets might make me miss cables popping in from another room...