Replacing your porch light with a security light is an easy afternoon project. Outdoor security lights use infrared or microwave sensors to light up whenever someone or something passes within a certain range. Use them to safeguard your house without the expense and inconvenience of leaving a harsh light glaring all night. You wire a security light just like an indoor ceiling or wall fixture. To replace an outdoor light fixture with a security light, follow these steps:
Turn off the power at the fuse or circuit panel.
You may find several pairs of wires in the wall box. Some of these wires may be wired to different circuits than the fixture you're working on. Be safe: Use a circuit tester or turn off the power to the whole house to ensure that all the wires in the box are dead.
Remove the light bulb cover and bulb from the fixture.
Unscrew the screws or nuts holding the fixture base to the wall box.
Lower the fixture base and remove the electrical tape or wire nuts from the black (hot), white (neutral), and, if present, green (ground) wires.
Use wire nuts to attach the wires from the new fixture to the corresponding wires in the electrical box.
Raise and position the new base plate so that you can screw the new bolts through it to attach to the mounting strap.
An outdoor fixture has a weather gasket that's inserted between the utility box and the cover plate of the fixture. The gasket helps prevent water from getting into the box. Use the gasket, even if you install the light in a weather-protected outdoor area.
Screw in the bulb and replace the bulb cover (if any).
Turn on the power and try out your toy.
Most units have a sensitivity adjustment. You may have to do a bit of experimenting with this setting to prevent the light from turning on when a bird flies by or the neighbor's cat strolls into your yard at 3 a.m. Have a helper walk into the sensor's field of view. If the unit doesn't light up, increase the sensitivity until it does.