phil@ux1.cso.uiuc.edu (10/22/90)
*** WARNING *** DO NOT ATTEMPT ANY OF THE EXPERIMENTS DESCRIBED HEREIN *** Back in my college days, which were just an extension of my high school days, I was sometimes rather destructive. I was the type to short circuit 110 volt plus with a loose solder bridge and leave the devices unplugged. When they were plug back in, the results were a bright flash, some solder vapors, and charred rosin residue blackening the outlet. I also made a shorting device out of a heavy duty 110 volt plug, some 10 gauge wire, and a 20 AMP "3 way" switch connected in parallel. I would plug the device in while open, then close the switch. Thus I did not have to see the sparks (instead they were burning up the switch contacts). The life expectancy of the device turned out to be about 50 uses on average. The usual failure mode was the switch fused in the closed position. That resulted in sparks on the (n+1)th attempt. Usual experiences with this device included a clanging sound from the walls. I suspected this to be the sudden rise and fall of the magnetic fields on the conduits. Most circuits I ever shorted were wired in conduits. One experience I had while using shorting device number 3 differed from the others. I was staying in a 4-person dorm room with only 1 roommate since it was summer. I was going home that weekend but my roommate was not. I decided to leave him a "complication" for the weekend. I shorted out the outlet circuit in room 1. There was the usual clanging sound, the blink of the lights (on another circuit but obviously on the same phase), and the shutdown of other devices on that circuit. I went into room 2 and found things there still working, and shorted that room's circuit in the same way with all the same effects. But the overhead lights were still on and I would have liked to get them off as well. After puzzling over the light circuit, I tried to turn on the light over the mirror and found it to be working. I hoped that this light was on the same circuit as the overhead lights. It had a utility outlet such as for an electric shaver so I was in luck. As I shall describe in the next paragraph, I was never able to determine this for sure. I plugged the shorting device (in open state) into the utility outlet. So far all was normal. Then I threw the switch to close the circuit and this is when the "fun" began. Instead of the expected clanging sound, I heard instead a loud buzzing and rattling combination sound. All the lights in the room went out when I closed the circuit, but the sound continued. After a few seconds of this, I decided something was wrong (gee, how obvious) and opened the switch. The buzzing and rattling sound stopped, and all the lights (including the one over the mirror) came back on. The wire portion of the shorting device was extremely hot. The plug body itself was so hot I figured I should not touch the prongs. I could feel radiated heat from it. I estimate the time of this shorted circuit to be about 5 seconds. I hid the shorting device in my suitcase and prepared to take it home (as I usually did on home trips anyway) with plans of retiring it and dissecting it as well (to see what damage took place to the switch contacts). I never did get around to doing that. On my way out, I went through the lobby and overheard a couple people talking about the "power failure". I asked them what they saw, and they said "the power went out for a few seconds". This was a dorm building with about 300 rooms, many of which were the double type for 4 people. It had its own set of three substation type transformers in the garage level under the first floor. How many amps do you think might have peaked out through this circuit? Why might the circuit breaker have not tripped? What damage to anything might have taken place (besides my device)? --Phil Howard, KA9WGN-- | Individual CHOICE is fundamental to a free society <phil@ux1.cso.uiuc.edu> | no matter what the particular issue is all about.
gil@limbic.ssdl.com (Gil Kloepfer Jr.) (10/22/90)
In article <34700035@ux1.cso.uiuc.edu> phil@ux1.cso.uiuc.edu writes: >*** WARNING *** DO NOT ATTEMPT ANY OF THE EXPERIMENTS DESCRIBED HEREIN *** You can say that again... >I also made a shorting device out of a heavy duty 110 volt plug, some 10 >gauge wire, and a 20 AMP "3 way" switch connected in parallel. I would >plug the device in while open, then close the switch. [...] >Usual experiences with this device included a clanging sound from the walls. >I suspected this to be the sudden rise and fall of the magnetic fields on >the conduits. Most circuits I ever shorted were wired in conduits. It was a good thing too... Many homes/dorms/etc. are not necessarily wired with good workmanship in mind. You're lucky that all you heard was clanging from conduits. There are some electricians who cut corners on wiring by using the absolute minimum gauge wire for the job, making splices without putting them in junction boxes...then there's always the happy homemaker who tries to do his own wiring. When you threw the switch on your shorting device, in the time period before the circuit breaker tripped or fuse blew, the wires in the wall underwent quite a stress. Any places where wires were spliced (either in junction boxes or at outlets) probably got awfully hot. If any of the connections were loose enough to create a spark or thin enough to get extremely hot, there could have been one heck of a fire. To make a long story short, shorting-out electrical wiring is NOT something you'd like to keep doing. I know they did it in one episode of _Mission_Impossible_, but it's far from safe. I'm sure some real electricians could probably shed some more light on this, as well as EE's who will know all the theory about it. I'm more of the practical kind who can do some of his own electrical repairs, and respects electricity. -- Gil Kloepfer, Jr. gil@limbic.ssdl.com ...!ames!limbic!gil Southwest Systems Development Labs (Div of ICUS) Houston, Texas
grege@gold.GVG.TEK.COM (Greg Ebert) (10/23/90)
In article <34700035@ux1.cso.uiuc.edu> phil@ux1.cso.uiuc.edu writes: > > [good stuff] > >Usual experiences with this device included a clanging sound from the walls. >I suspected this to be the sudden rise and fall of the magnetic fields on >the conduits. Most circuits I ever shorted were wired in conduits. > > [even better stuff] > I had a similar effect when I plugged-in my 120v/20A isolation transformer. It got REALLY annoying, especially when it poinked the breaker during a blizzard. It was truly amazing that enough force was there to cause 10 gauge wire to rattle. In fact, I *knew* when the breaker popped based on the tonal qualities. I was terrified that the inductive spike might zap whatever else was on the same circuit. I made a 'zero-cross' switch with a triac, and then shorted-out the triac after power-on. No more rattles. By the way, regarding current spikes, I poofed a $50 darlington (800v/30A) because an extra 18" of wire had too much 1/2LI**2. >--Phil Howard, KA9WGN-- | Individual CHOICE is fundamental to a free society ><phil@ux1.cso.uiuc.edu> | no matter what the particular issue is all about. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ AMEN , AMEN , AMEN !!!! ----- Boycott redwood products ---------------------------- Recycle ----- ##### {uunet!tektronix!gold!grege} Register to vote, then ## | ## grege@gold.gvg.tek.com vote responsibly # | # # /|\ # Support the First Amendment, not the party that attacks it #/ | \# "I was, BANNED in the USA" - 2 Live Crew #######