Brain Teaser

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stickboy1375

stickboy1375

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Litchfield, CT
If you had Three light switches in a basement, and each switch controls a single light fixture in the attic, The homeowner wants the switches labeled, but you can only go to the attic ONCE....What do you do?
 
Turn one switch on, and put a toner on another swtich's conductors.

When you go to the attic, one light will be on, one light will have a tone on it, and one light will be dark with no tone.

Write bill for service call.
 
Alternate method.... have homeowner operate switches while you are in the attic and holler back and fourth.

Why is this a brain teaser? I have at least 2 other methods in mind.
 
mdshunk said:
Turn one switch on, and put a toner on another swtich's conductors.

When you go to the attic, one light will be on, one light will have a tone on it, and one light will be dark with no tone.

Write bill for service call.
Click to expand...

You forgot your tools you can't actually work on the switches
 
mdshunk said:
Alternate method.... have homeowner operate switches while you are in the attic and holler back and fourth.

Why is this a brain teaser? I have at least 2 other methods in mind.
Click to expand...

Homeowner is not home you are alone..
 
Since you have the box open anyway.use the switch legs,#1 hot to neutral,#2 hot to ground,#3 neutral to ground and test at the fixture socket with a continuity tester.
 
If each sw. controls a single fixture in the attic then you don't have to even

go to the attic, just label them all " single fixture in attic"
 
Leave one switch on, leave on switch off, leave the third switch on for a few minutes and shut it off. Now climb in the attic, the light that is on will be lit, the light that is off and cold will be the one you didn't turn on, the light that is off but warm will be the one you turned on and shut off.
 
Trevor's answer is the reason this is a brain teaser. I had heard it before in a different context, but the reasoning was the same. It takes a little "thinking out of the box" to realize that a switch that is now off, but that was on for a while, will give you a lamp that is dark but hot, and to realize that using that concept can help you tell the three switches apart.
 
This works as long as you can go to the panelboard (wide grin)

1. Leave switch one off.
2. Place 3A 125V UL 1077 circuit breaker in series with switch 2.
2. Turn on switches two and three.
3. Go to attic.
4. Identify off fixture as switch one load.
5. Remove either of the two on lamps and install 5/16" x 12" Klein screwdriver, being sure to make contact with both the base and the thread of the socket. (Note: Wear gloves and eye protection.)
6. When socket stops throwing sparks, remove Klein screwdriver and replace lamp. Identify charred lamp fixture.
7. Return to basement. If UL 1077 OCPD is cleared, identify switch 2 as switch supplying lightly spalled lamp socket identified in (6) and discard UL 1077 device, as it has reached end-of-life. If branch circuit UL 489 OCPD in panelboard is cleared, identify switch three as the switch associated with the heavily damaged lamp socket identified in (6) and reset breaker.

Of course, there are other possible variations, including the use of two UL1077 breakers...

Ugh. No tools, huh? I'll think some more.
"Well, we had to forget somethin' or we wouldn't be plumbers." - Moe Howard

Dan
 
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Turn all the switches off. Find a radio belonging to the HO, cut the plug off the end of radio's cord and strip the ends. Remove and smash a lightbulb, insert busted lightbulb base into the lamp holder you want to figure out, connect stripped cord to wires left in light bulb's base. Go back downstairs, turn switches on one by one until you hear the radio.
 
tallgirl said:
Turn all the switches off. Find a radio belonging to the HO, cut the plug off the end of radio's cord and strip the ends. Remove and smash a lightbulb, insert busted lightbulb base into the lamp holder you want to figure out, connect stripped cord to wires left in light bulb's base. Go back downstairs, turn switches on one by one until you hear the radio.
Click to expand...

Nope you only get 1 trip
 
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