How to..

JF1091 · 10-13-2007, 02:02 PM

For a class, I need to do a demonstration speech. I decided I'll demonstrate how you would go about changing a light switch into a dimmer. I was thinking of having a J box with a light switch installed, connected to a battery as the power source, and a light bulb in a socket on the other end. I would then show how it just turns the bulb on and off. I would then remove the light switch, and install a dimmer, then show how the bulb dims and brightens.

How should I go about doing this?

Thanks
- Jay

Big Bob · 10-13-2007, 02:09 PM

How old are you Jay? And will you have any help at home setting this up?

I think it great you found this site and have asked how to do this.

JF1091 · 10-13-2007, 02:16 PM

16 and Yeah but I'm pretty good with this kind of stuff.

jwhite · 10-14-2007, 07:15 AM

The only problem I see is that a normal light dimmer may not work correctly using a bulb powered by a battery. You could use a Potentiometer, but it would not likely fit correctly into a standard wall box.

jproffer · 10-14-2007, 09:01 AM

Is there a receptacle nearby? You could add that turning the breaker off (unplugging the board) is ALWAYS the first step.

jwhite · 10-14-2007, 09:23 AM

Get a bit of plywood and cut it to one foot by 3 foot.

Get a plastic single gang box and a plastic round light box and screw them to the plywood.

Get 6 feet of no. 14-3 SO or SJO cord and a Cord cap.
Get 6 feet of 14-2 w ground romex.

Put the cord cap on one end of the extension cord. Remember that the hot wire (black) goes on the darker color screw, and the ground wire goes on the green screw.

Get a single pole switch, a dimmer, and a keyless light fixture and bulb.

run the so cord and romex into the single gang box.

You will also need some electrical tape, a few wirenuts, and some staples.

splice the white wires through the box. Splice the grounds through and leave a pig tail for the ground screw on the switch.

the black wire from the cord and the black wire from the romex one to each of the screws on the switch. Wrapp them clockwise around the screws.

Run the other end of the romex into the light box. The white wire ties to the silver color screw and the black to the darker color screw. (white to the screw shell of the fixture, black to the center pin of the fixture.) connect the ground wire if the fixture has a green screw.

Staple the cables neatly down to the plywood. do not drive the staples too far.

Ask an adult to check your work, and have them be there when you plug in your project.

After you check your work, and before you plug it in, screw the light fixture and switch down to the boxes.

Plug in your project and check the switch works properly.

Next unplug your project and take out the switch. Connect the same three wires from the switch to the dimmer. Screw the dimmer down to the box, and ask the adult to help you plug the project back in.

Check your dimmer for proper operation.

As suggested mention that one must turn off power At The Breaker Panel before doing any electrical work. Use unplugging the cord as your way of insuring that you are not working on a live circuit. Re state that one should NEVER work on a live circuit.

jwhite · 10-14-2007, 09:26 AM

I forgot to add that if you have any questions post them back here in this thread.

J. V. · 10-14-2007, 10:52 AM

You may want to show that a CFL bulb cannot be dimmed. Just interchage it in place of the incandesent bulb. You can dim a CFL slightly but the range will be miniscule.

Don't use the battery. Not enough power for the dimmer or 120 volt bulb. Use the corded idea mentioned above. 120 volt. Do not let anyone touch your project but you. And make sure the cord is unplugged during the switch and bulb changes. Good Luck. Sounds like a really cool demonstration.