Motion detector detector lights are activated by a motion sensor light switch, as opposed to a conventional light switch. The motion detector  switch can either be fastened to an existing outdoor light or substituted for a conventional light switch.

If you are looking for reasons for installing such a switch to one or more of your outdoor motion sensor lights, considering the following benefits:

(1) Exterior motion sensor lighting acts as a deterrent against crime and other mischief.  They  also light up dark and hidden corners of your yard exactly when you need it. On top of all this, they offer visitors the ability to navigate your lawn without stress or worry.

(2) Motion activated outdoor lights conserve electricity, which benefits the environment. This is accomplished by switching on when a person or object is detected in the sensor area and staying on for a pre-determined fixed period of time.

(3) Installing motion detector switches is a proven money saver. They also are relatively inexpensive to purchase. As a general rule of thumb, you should expect to recover money spent on a motion sensor light switch within a year or less. Obviously this will depend on what type of motion switch you purchase, but you should realistically expect your investment to pay for itself within a year.

(4) Installing a motion sensor is a relatively fast and simple undertaking. From start to finish, it should only take about half an hour. But, since you’ll be working with electrical wires, you’ll need to take precautions to ensure this is done in the safest manner possible.

What follows are some basic instructions on how to install an exterior motion sensor switch.

You’ll need 3 things to get the job done:

(a) A screwdriver

(b) A circuit tester

(c) Wire strippers (cutters)


(1) Decide on the Location

The first thing you’ll need to decide is which part of your yard would most benefit from motion detector lighting. Most common areas include areas around the front door and garage. Don’t forget to keep in mind range of motion and lighting angle.

(2) Switch the Power Off

Determine which circuit is connected to the light switch you’ll be working on and shut off the power at the circuit breaker. To be doubly safe, tape a warning message on the cover of circuit box. You don’t want someone to accidentally switch the circuit back on while you’re working.

At this point, you’ll also want to go back outdoors to remove the bulb on the light you are working on. Then loosen the light fixture’s screws and carefully pull it away a few inches.

(3) Test the Wires to Make Certain the Power is Off and Remove the Switch

Remove the wall-plate that is attached to the existing switch. Then use a circuit tester to test the wires you’ll be working with. You want to be absolutely certain no power is flowing to them.

You can do is this by contacting one of the tester’s probes with the ground wire and contacting the other probe to one of the other wires. If using an audible-alarm tester, you’ll hear a continuous beep if power is still flowing.

If the power is indeed completely shut off, you can then take out the screws that hold the existing switch in place. After this, disconnect the wires and remove the existing outdoor light fixture.

(4) Remove/Mount Crossbars

If the existing light fixture is mounted with a crossbar, you’ll need to remove it. And if your new motion detector light comes with a mounting crossbar, this is the time to install it.

(5) Inspect the Wires

Here you determine whether you have a “two-wire with ground “or “three-wire with ground”. If you see a total of three cables, one bare copper or green coated cable along with two black and/or white cables, you”ll know you have a “two-wire with ground”.

If you notices a total of four cables, one bare copper or green coated cable along with one black, another black or white, and one red, you’ll know you have a “three-wire with ground”.

The ground wire is the one that is either bare copper or green coated. The red and black wires are “hot” wires, and the white wire is neutral.

If you notice the wires have carbon deposits or appear worn, you’ll need to clip those wires back and strip 3/8 of an inch of the coating. This will reveal new wire.

If your house has aluminum wiring, you’ll need to make certain you have the right connectors. If not, you could be exposing yourself to a fire hazard.

(6) Connect the Wires

Most motion sensor light switches will include a wire nut to connect the electrical wires to the corresponding pigtails (i.e. short wires emanating from the back of the motion detector switch). Simply connect the white wire with the white wire, the black wire with the black wire, and the ground wire with the corresponding ground wire.

If mounted to a crossbar, secure the ground wires to it. (Most motion sensor switches will include a screw for this purpose).

(7) Push the Electrical Wiring Back in the Outlet Box

Once you have carefully pushed all the wiring back into the outlet box, you can then secure the fixture to the crossbar. This is done by tightening screws through the wall plate’s holes.

(8) Install the Bulb

Screw in the light bulb as usual and then attach any other ornamental parts or covers.

(9) Turn the Power Back On

Once the power is back on, you’ll want to make sure the light switches on.

Then you’ll need to aim the sensor in such a way that it switches on when a person or object walks through the “sensor area”, but doesn’t switch on when objects or people approach beyond the sensor area.

When adjusting the lamps, do so by holding the lamp holders, rather than the bulbs themselves (which are fragile). You’ll want to aim the bulbs away from the sensor to prevent the sensor from switching the lights back on again once it has automatically turned off.

Finally, you may have to adjust the sensor’s sensitivity until you have the settings just right.

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