I have had a set of these Novi 4-channel wireless intercoms for over 12 years. Mine are set up on different wiring circuits in my current home, and they work just fine. I'm not sure why other people are having trouble with them not working on different wiring circuits. One caution: I used to live in a condo, and, apparently, one of the neighbors received a set as a Christmas present, because we began to hear their conversations the day after Christmas. We just switched channels, no more problems.