I bought this Leviton DDS15 to replace an aging Intermatic timer that had become erratic. I was never a fan of needing to manipulate the tiny buttons hidden behind the manual on / off switch on that device at least twice a year when Daylight Savings Time started and ended but there were no other options at the time. I am controlling three exterior lights on the front of my house and since those lights can be turned on or off in two different locations, I also purchased the DD0SR companion switch because I have what is commonly called a 3 Way switch set up. The quick change front plates for white, ivory and almond all coming in the box is a nice feature, I can see where it would be very beneficial for both those who sell these units (to keep inventory to a minimum) and for people who are in the industry, such as electricians or lighting control people, since there is no need to stock three different colors. It also appears that you can special order color change kits if you want other colors besides the three that come in the box. The 3 way installation isn't for a novice in electrical wiring, the instructions are clear, you just need to be sure you are reading the section that applies to your particular situation. Since my 3 way installation encompassed only two physical locations that is the situation I am commenting on. First, set aside any knowledge or previous experience you may have connecting 3 way light switches, that was the hardest part for me. Once I started with a "clean slate" with no preconceived notions based on past experience the process went much better. Second, the DDS15 and the DD0SR both need a connection to the neutral electrical wire. This is much different than any timer I had ever connected before because none of the previous units I have installed needed neutral, even the simplest regular light switch has no need for a connection to the neutral wire. Third, you need to be sure you know which wires go to the load you want the timer to control (in my case the front lights). You also need to know which wires are supplying the electrical power to the box you are working in and do not even think about hooking this timer up without shutting off the breaker that supplies power to the box. If you are not familiar with how to accomplish these preliminary tasks, play it safe and get a hold of someone that does. This is not an installation where you can "get through it by trial and error". Those who have hooked up three way switches before will recall there is usually a cable containing four wires that runs between switch locations, and usually there is a white, black, red and ground wire contained within such cables. Since I had the cable that supplies the power to the box from the breaker panel, and the cable that went to the lights (the load) as well as the four wire cable to the other switch location in the same electrical box, that is where I placed the DDS15. The instruction sheet that comes with the timer has a specific section for this situation, they also have sections for other possible situations. I removed the existing timer and the switch at the other switch location before I began the hook up of the DDS15. As I mentioned above older timers didn't need a connection to the neutral (usually white) wire, but both of these devices do. Since there was no neutral wire in the second switch location, I went back to the wiring instructions. What I found was that out of the four wires in the cable between the two switch locations, I only needed to connect three of them including the neutral. That is the big difference between these devices and a normal three way switch installation between two locations. These devices use the neutral wire and one other wire as a communications pathway between them instead of actually carrying power between the two switch locations like a normal 3 way installation would. In this case the instructions said connect neutral to both devices at the appropriate location and one wire between the terminals on the two devices marked "red/yellow" along with the ground wire on each device. I used the white wire of the four wire cable to carry the neutral from the box where the DDS15 was to the second switch location solving the problem of no neutral in the second box. I chose the red wire to go between the two "red/yellow" terminals on the two devices. I connected the grounds and coiled the black wire on the four wire cable up on each end and tucked it in the box since it isn't needed for this type of install. The other connections to the DDS15 are pretty standard, one for the incoming power, one for the load being controlled. So, essentially the DDS15 does all the actual turning on and off of the lights, the DD0SR is called a companion because it just signals the DDS15 to turn the lights on or off from a different location. Once everything is connected, you restore power at the breaker panel and touch the top of the rocker switches on each device to turn the lights on and touch the bottom of those same rocker switches to turn the lights off. There is a little green LED that is on when the lights are off, and off when the lights are on which is similar to how an illuminated light switch works. If the turn on / turn off test passes, you are ready to button everything up at the switch location(s) and download the app so you can connect to the DDS15 via bluetooth from your smartphone or tablet for programming. Since I want the front lights to come on at sunset and go off at a preset time, but come back on in the early morning hours when I leave for work and go off at sunrise, I thought that would be a huge task to program. I was completely wrong about that being difficult. The programming couldn't have been easier. If you want the timer to do something at sunrise or sunset, be sure to have your location services option enabled on your smartphone or tablet when you program the timer. It also helps to have your WiFi on because the timer uses the location information from your smartphone or tablet to determine the latitude and longitude of your location. It uses this information to automatically adjust the time it does its turn on / turn off thing based on the sunrise and sunset times for your particular spot in the world. That is huge, no more fooling around with the timer during the twice yearly daylight savings time clock adjustments and no more adjusting for the changing amounts of daylight between winter and summer. Set up the timer and it does the work for you, and it does it better than you could, since it adjusts itself daily if you use the sunrise or sunset functionality.
