Unlike regular lights, spotlights produce a concentrated, focused beam. It is useful outside for highlighting landscaping or providing security, and it is also useful indoors when you want to accent a feature in a room, or give yourself extra reading light. Whether they are installed indoors, in the exterior wall of your house, or on a stake somewhere in the garden, wiring spotlights is exactly the same as wiring convention light fixtures. The only complication arises outdoors, when you have to run cables underground and use waterproof fixture covers.
Find a convenient location for a switch on an interior wall and outline the back of a remodelling switch box on the wall. Cut around the outline, using a drywall saw. If you want to place the switch on an exterior wall, drill a 1.25 cm (1/2 inch) hole in the wall and screw an exterior electrical box over the hole.
Run a length of 12/2 type NM electrical cable, which is for indoor use, from the main panel to the switch box. Turn off the main breaker in the panel, loosen one of the cable clamps on the bottom or side with a screwdriver, and feed the wire through. Tighten the clamp to hold it.
Strip sheathing from the cable with a utility knife, and expose the ends of the black and white wires with a wire stripper. Connect the bare wire to the ground bus by loosening an available lug with a screwdriver, inserting the wire, and tightening the lug. Connect the white wire to the neutral bus in the same way. Connect the black wire to a 15-amp circuit breaker and snap the breaker into a slot on the hot bus. Turn that breaker off, then turn on the main breaker.
Run the cable through the attic or basement to the wall on which the switch will be located, drill a 1.25 cm (1/2 inch) hole in the top or bottom plate, and pass the cable through the hole. Run another cable from the switch to the location of the spotlight. If the spotlight will be in the garden, use type UF cable that you can bury underground.
Drill a 1.25 cm (1/2 inch) hole in the side of the house at the location of the spotlight, if it will be mounted on the house. If it will be in the garden, drill the hole in the siding near the ground and screw a 90 degree plastic access fitting over it. Pull the cable out of the hole. If there is an access fitting, feed it back into the other leg of the fitting and run it to the spotlight. Dig an 45 cm (18 inch) trench and bury the cable for the full distance from the house to the spotlight.
Feed both cables at the switch through the back of the switch box and insert the box into the hole. Turn the screws in front with a screwdriver until the anchors in the back hook behind the wall. Tighten the screws to hold the box to the wall. If the switch is mounted outside, feed the cables through the back of the exterior box.
Strip the cable and the insulated wires, then connect the black wires to the brass terminals of a switch. Twist the white wires together and screw on a wire cap. Twist the bare wires together, leaving one end longer than the other. Connect the long end to the green ground screw on the switch. Screw the switch to the box, then screw on a cover. Use a waterproof cover if the switch is mounted outside.
Place a waterproof gasket around the electrical box for the spotlight. Connect it by twisting together the black wire from the light together with the black wire from the cable and capping them. Repeat with the white wires. Twist the bare ground wire from the cable together with the bare or green wire in the light, but you don't need to cap these wires. Fit the spotlight onto the electrical box and screw it in place.
Turn on the breaker and test the light.
Spotlights draw more power than ordinary lights. It is advisable to wire the spotlights to a separate breaker so you don't overload other circuits.
You can add another spotlight to the circuit by running a cable to it from the first one. Twist wires of the same colour together at the first light, and wire the second light as you initially wired the first. Add additional spotlights in the same way.