I think iD has a key you hold to disable snapping completely. I rarely use iD as I got used to JOSM early on.

I just put cables in a general area and try to keep them as far away from any road or sidewalk as I can without spending to much time on it.

In JOSM it is easy to disable items with specific tags to avoid messing with them by filtering. So if I do roads I can set an inverse filter for "highway" and then only ways with that will be active. I do the same when mapping power infra.