ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 263 guests, and 17 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
#71325 10/26/06 05:16 PM
Joined: Jan 2006
Posts: 558
R
Rewired Offline OP
Member
This one was told to me by a plumber today at the jobsite. Its easy I figured it out [Linked Image]

You have 3 lights up in the attic of a building. These 3 lights are controlled by 3 individual switches in the basement of the building. You must identify which switch controls what light BUT, you can't obviously see the lights from the basement.
How do you identify what light is controlled by what switch without the use of any tools except maybe a stepladder if needed to reach the lights, and with only making ONE trip from the basement to the attic. Assume the lights could have just recently been on and might still be hot.



A.D

#71326 10/26/06 05:33 PM
Joined: Jul 2006
Posts: 23
R
Member
Aw! You should edit out your last sentence.

#71327 10/26/06 05:40 PM
Joined: Aug 2005
Posts: 265
S
Member
(the last sentence gave the clue)

I deleted my post so others can have a chance at guessing it.

[This message has been edited by Sixer (edited 10-26-2006).]

[This message has been edited by Sixer (edited 10-26-2006).]


Sixer

"Will it be cheaper if I drill the holes for you?"
#71328 10/26/06 07:18 PM
Joined: Feb 2002
Posts: 182
B
Bob Offline
Member
Turn sw#1 on and leave it on for 1 minute.
Then turn it off.
Turn on sw#2 and leave it on.
Goto attic and climb ladder.
Feel the off bulbs. The hot one is on sw#1
and the other is on sw#3.

#71329 10/26/06 07:35 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
I heard this one on Car Talk....


Mark Heller
"Well - I oughta....." -Jackie Gleason
#71330 10/26/06 07:39 PM
Joined: Jul 2005
Posts: 73
S
Member
Step 4 re-wire lights to one switch and locate switch near attic access!!

#71331 10/26/06 10:31 PM
Joined: Nov 2005
Posts: 827
Likes: 1
J
Member
It was an easy solution but I started wondering how MacGyver would've done it. I'm pretty sure he would've started by taking apart the clothes dryer. He might also have left the switch on and looped a string with a weight, secured to the rafter, around the handle. The can of spray starch would act like a blow torch ,(see also: James Bond, "Live and Let Die" venomous snake application), on the string. This would create a precise, for MacGyver, time delay, allowing ample transit time to the attic. Now, if he can only help Dana Elcar grow his hair back and get him to stop picking on Pappy Boyington!
Joe

#71332 10/27/06 01:08 PM
Joined: Mar 2005
Posts: 1,803
Member
One of the bulbs has been 'borrowed' by a sheetrocker: How many trips to the attic do you need to do to be 100% sure which switch operates which bulb?

Alan


Wood work but can't!
#71333 10/27/06 01:52 PM
Joined: Dec 2004
Posts: 1,064
D
Member
Make one trip up there and install a camera?

#71334 10/27/06 04:51 PM
Joined: Nov 2002
Posts: 794
Likes: 3
W
Member
Quote
One of the bulbs has been 'borrowed' by a sheetrocker: How many trips to the attic do you need to do to be 100% sure which switch operates which bulb?

Well, if neither of the two remaining bulbs is on, but one is warm, the missing bulb must be the one that's "on". Vefify by taking one of the two remaining bulbs to try it in the empty socket, it should light. You don't have to leave the attic. One trip

Or if one is on, and the other is warm, then the missing bulb is the one that was always off. Or if the dark bulb is cold, then the missing bulb was the one that would have been warm. One trip

Page 1 of 2 1 2

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5