Wire a remote sensor to operate light fixtures anywhere around the house.
Time A full day
ComplexityIntermediate
Cost$51–100
Introduction
A remote sensor automatically lights up dark sidewalks and yards. And it'll operate any light fixture. In this story, we'll show you how to install a remote motion detector to your outside lights.Tools Required
- 4-in-1 screwdriver
- Corded drill
- Drill bit set
- Extension cord
- Jigsaw
- Non-contact voltage tester
- Safety glasses
- Stepladder
- Utility knife
- Wire stripper/cutter
Materials Required
- 14-2 cable
- Junction boxes
- Motion sensor
A gangly-looking motion detector floodlight is fine for scaring off a backyard intruder, but it doesn’t look good on your house. A remote-style motion detector is a better choice. You can connect it to any type of decorative fixture—even existing ones—and mount it discreetly off to the side.
This article will show you how to install and connect a remote sensor to new or existing lights. The wiring is a little more complicated than it is for most electrical projects, but even a novice can handle it by following the wiring diagrams we provide. We won’t detail the most basic aspects of electrical work, so you may need to do some further reading.
Apply for an electrical permit at the local inspections department so an inspector can check your work. The toughest part of this project may be running the wires that connect the sensor to the light fixtures.
In some situations, you can “fish” wires through finished walls. But in many cases, this project is only practical where you have open studs, as in an unfinished garage (as we show), or during a major remodeling project. If new wiring isn’t an option for you, consider sensors that give you similar results but with little or no rewiring.
Project step-by-step (10)
Step 1
Choosing a sensor
Home centers and hardware stores carry motion sensors ($20) that look like the ones you see mounted on floodlights. They’re usually labeled as “replacement” sensors for floodlight fixtures, but you can attach one to a mounting plate and use it as a remote sensor.
Before you buy a replacement sensor, add up the wattage ratings on the fixtures it will control. The wattage rating of the sensor must be at least as high as the total watts of the fixtures. For example, if you have two fixtures, each rated to hold a 100-watt bulb, the sensor must be rated to handle at least 200 watts.
Step 2
Cut junction box holes
Hold the box against the wall and trace around it with a pencil. Avoid placing the box directly on a stud or other framing. With brick or stucco, use a 1/4-in. masonry bit to drill a series of holes all around the circle. Then, break out the middle with a chisel (Photo 1). On stucco, you’ll have to cut the exposed metal mesh with snips. Cut out the sheathing behind stucco with a jigsaw.
Step 3
Fasten the junction boxes in place
If you have wide lap siding made from wood, cement board or hardboard, cut your hole near the center of a board so you can mount the fixture on the flat surface. If you have vinyl siding or siding courses that are too narrow to provide a flat mounting surface, you’ll need a mounting block that fits over lapped edges. Plastic blocks are available at home centers.
Step 4
Figure A: New Junction Boxes and Cable
The sensor and each light fixture require electrical boxes installed in the wall.
Step 5
Wiring options
Before you run electrical cable to the junction boxes, you have to determine how you’ll wire your system. We show the simplest method here: drawing power from a switch box and running cables to the sensor and then light fixtures. You can also run the cable to a fixture and then to the sensor. But cable and connection details will vary a bit.
Simply choose the method that will make running cable easier. If your sensor will be placed close to the switch, the method shown in Figure B is probably best for you. If a light fixture is closer to the switch, the method shown in Figure C is probably best. Both illustrations include additional light fixtures. If you have a single light, just eliminate the wiring that feeds the second fixture. Your system must have a switch that can turn off the power to the sensor and light fixtures. We used an existing switch in an existing junction box; you may need to add a box and switch.
With either method, you can add as many fixtures as you like as long as you don’t exceed the wattage rating of the sensor. Boxes have to be a certain minimum size to contain the wires. A 16-cu.-in. box is adequate for all the wiring configurations we show here.
Figure B: Sensor Between Switch and Lights
Running cables from an existing switch to the sensor and then to the light fixtures is the simplest way to wire your system.
Figure C: Sensor Between Lights
Running the cable to a fixture and then to a sensor is the best choice if a light fixture is close to the switch.
Step 6
Run cable to junction boxes
Drill 5/8-in. holes in the center of the wall framing to create a path for cable. Then run the cable between the junction boxes. Fasten the cable to framing with plastic cable staples.
Step 7
Insert wires into the boxes
Strip off 12 in. of the cable’s sheath and feed wires into the box. If two or three cables enter a box, label wires with masking tape and a marker to avoid confusion.
Step 8
Wire the sensor and fixtures
Connect the sensor and the fixtures as shown in the wiring diagrams. Hang fixtures on a leftover piece of wire while you make connections.
Caution: Turn off the power at the main breaker panel before removing the cover of the electrical box you intend to use as a power source. Check the wires inside with a voltage detector to verify that the power is off.
Step 9
Adjust the sensor settings
Adjust the sensitivity and “on-time” of the sensor according to the manufacturer’s instructions.
Step 10
Energy-Saving Bulbs and Sensors
Power-saving compact fluorescent (CF) light bulbs designed for outdoor use are becoming more popular and economical. Unfortunately, most motion sensors aren’t designed to handle CFs. Some sensors tell you right on the packaging whether they work with CFs. With other sensors, you have to check the wattage rating in the specifications. If the wattage rating specifies “incandescent” lighting but doesn’t mention “fluorescent,” assume it won’t handle CFs. The Tuff Dome sensor shown here is CF-compatible.
Sensors That Don’t Require New Wiring
Built-in sensors
Some outdoor fixtures have a built-in sensor. These decorative lamps operate like floodlight motion detectors but are more stylish. Like any other light fixture, they take just a few minutes to install. They’re not designed to control other light fixtures and are available in a limited range of styles.
Wireless motion sensor lights
A wireless sensor works like the remote control for a garage door opener. It sends a radio signal to a receiver that switches on a light. No wiring is necessary to control existing lights. Just screw the receiver into a light socket and mount the sensor anywhere you like. There are some limitations to this system, though. The sensor requires batteries, which you’ll have to change every few months. In rare situations, the radio signal can’t reach the receiver because of interference or blockage. Finally, the shade or globe on your light fixture has to be large enough to hold the receiver along with a light bulb.
