Use an energy-efficient fluorescent light bulb in a shower light fixture.
Unlike other light fixtures in a home, light fixtures for showers and tub-shower enclosures are vulnerable to moisture. If the light flickers or doesn't work at all, there's a good chance that it must be replaced. Surface-mount and recessed lights with watertight globes are available at home centers and lighting stores. Obtain a light fixture of the same type as the existing fixture and organize a few tools to do the replacement before starting to speed the job along.
Climb a stepladder. For a surface-mount fixture, loosen the setscrews at the upper rim of the globe with pliers and remove the globe. For a recessed fixture, loosen the screws at the face of the globe's rim with a screwdriver and remove the rim and globe. Unscrew and remove the light bulb.
Turn off the breaker for the bathroom circuit at the electrical panel. If the breakers aren't labeled, use an electrical tester to identify the circuit breaker. To do this, set the tester on "Volts" and touch the tip of one tester-wire to the rim of the light socket and the tip of the other wire to the contact inside the socket. If the tester shows a reading, turn off a breakers one at a time and repeat the test at the light socket each time until the tester doesn't show a reading. .
Loosen and remove the screws that secure the light fixture at the electrical box in the ceiling, and pull the fixture down to access the wires. Remove the wire nuts that connect the pairs of black and white wires, by twisting each nut counterclockwise. Loosen the screw that connects the end of the green wire, or ground, to the electrical box. Remove the old light fixture.
Pull off the short section of the insulation at the ends of the black, white and green wires. If the sections aren't precut by the manufacturer, strip off 3/4 inch of the insulation at the end of each wire with a wire stripper or electrical pliers.
Connect the bare end of the ground wire at the electrical box where the old wire was connected, using the short, green screw that came with the light fixture. Connect the ends of the black and white wires for the fixture to the corresponding black and white wires with the provided wire nuts for the light circuit. Screw the nuts clockwise and tighten them securely by hand.
Cut two, 3-inch-long strips of electrical tape, using a utility knife. Wrap a strip of tape around each wire nut and continue the wraps 1 inch onto the corresponding pairs of black and white wires.
Install the light fixture at the electrical box in the ceiling by driving one of the provided screws through each of the machined holes at the fixture and into the corresponding threaded holes at the box. Tighten the screws securely and install a bulb in the light socket.
Apply a uniform bead of clear silicone sealant around the upper rim of the new globe. Fit the provided circular rubber gasket at the rim and press it onto the sealant. For a recessed light, align the holes in the gasket with the holes at the rim of the globe. Install a surface-mount light globe by tightening the provided setscrews at the upper rim. For a recessed light, secure the rim of the globe with one of the provided screws at each hole at the rim.
Light fixtures and installation vary with the manufacturer. Always refer to the installation instructions beforehand and become familiar with the procedures.
Always use electrical tape at wire nuts and wire connections. Do not use masking tape or duct tape.
Do not remove or install a light fixture unless you are certain the electrical circuit is inactive. If necessary, turn off the main breaker at the electrical panel or enlist an electrician to identify the circuit for the fixture.
Machin, William. "How to Install a Shower Light Replacement." Home Guides | SF Gate, http://homeguides.sfgate.com/install-shower-light-replacement-58688.html. Accessed 22 April 2019.