Adding Z-Wave to a complicated circuit in your older home

Adding Z-Wave to a complicated circuit in your older home

So not only do I do a little Z-Wave product explanation, some DIY electrical work, I can now say I've invented a new category: Electrical archeology.

Way back in April of last year, I tried to convert my basement TV room to total Z-Wave control. The places where it was newly installed (by me), the installation was no problem. But determining the correct path to replace my aging 3-way switches proved to be too much for me at the time. My work-around; using a motion sensor and Domitech LED bulb, worked so well that I left the Aeotec Micro Smart Illuminator in its box for the past 6 months. However, that was not a ideal solution, and not the project that would be completed by a guy who writes blogs about installing Z-Wave in your home.

The concept behind the Micro Smart Dimmer and its cousins are simple; use your old switches and wire this device in-line. The wiring can make the seasoned DIY person struggle (not because of this device). It's good to know a few things going in.

•    This dimmer module is wired to your power, and feeds that power to the load. It is in complete control of operating the lights from now on.

•    Your old switch(es) only provide a signal to the low-voltage side of the dimmer module, and activate a relay inside the smart dimmer, cycling the power.                                                                       
           (At no time should you apply power to the switch side of the module or you will short it out, voiding its warranty).                                                                       
•    The low-voltage contacts are tiny and will not accept a 14/2 wire. I can only surmise this is to stop you from putting a 120VAC lead to the unit and frying it.

When I started this project in the morning, I first had to do some digging into the history of my lighting. I can only assume that at one point in my house's history, there was a porcelain socket and pull chain, with no switches. There was a tie-bar and octagonal box with a single BX line coming from the junction box that also served the kitchen above. As the basement began to be more utilized, a single 3-conductor wire (black, white, red + ground) was run to the top of the steps, and another was run to the entrance near the walk-out basement. I date this job to the late 1970's, due to the style of Romex wire, but it could have been done with a total house update performed in the 1980's.

When we moved into the house, we gutted the fake temporary walls in the basement and put up steel. This reorganization of space banned the single pull chain to the laundry room, which did no good for the TV area or coming and going through the egress. I capped off the junction box, ran a new circuit for the laundry light, and ran a new feed to new cans installed in the ceiling. That configuration worked well until I decided to automate those lights.

Thanks for bearing with me so far. I think it's important to know some of the history of your electrical project, especially if you are a 'do it yourselfer’

The Aeon Labs Micro Illuminator (Dimmer), shown below, surprised me in how small it was. I show it here with an old-work switch box for contrast, but the recommended minimum box size is 14 cubic inches.  


For me, the 3-Way circuit was pretty easy one to figure out once I broke down the parts. I mounted the Micro Dimmer in the fixture box where the light load wires leave. So in this one box I have power from the circuit breaker panel (hot, neutral) which I will connect to the power portion of the module; leads from the commons of both switches, which I will connect to the switch side of the module; and the load (hot, neutral) that serves the lights (cans in this case) which I will connect to the controlled portion (marked Load) of the module.  [I kept the ground continued to each section by terminating them together.] You could just as easily install this device in a large fixture box where your light is mounted. I would recommend removing the old box, and installing a new plastic one that can handle the required CU. (Aeon Labs suggests 14 CU minimum). If you choose the light location, you will have a neutral available, and any work to your ceiling should be covered up by the fixture itself (if it’s of sufficient size). You can use dumb switches in any color and style that you can find.

Adding the module to my existing Z-Wave network was really easy. The model I tested had an energy component to it, so the energy consumption of these lights showed up on my Vera. A nice touch.

Keeping track of the 4 types of modules available can be a little daunting. There is a Dimmer module (which has less amperage - only 2.5A - so measure your load) which Aeon Labs calls an Illuminator, there is a Switch (which has a better 10A load capacity), there is a Dimmer with Energy (again, 2.5A) and there is a Switch with Energy (10A). All 4 are great choices, and I feel this design will revolutionize many of the DIY projects with complicated wiring and/or no neutrals. There also is a module for controlling motors, but has not gotten samples for me to test.

Aeon Labs has a very comprehensive list of wiring solutions available here. Keep in mind, you still need to understand your portion of the circuit. Doing some research and understanding your home will pay for itself when you are able to tame even the most complicated wiring. I hope this helps.  If you get in over your head, please contact us, or better yet- a competent and licensed electrician. 
Back to blog