CryingDragon,
I'm glad you have a good sense of humor. I didn't want to offend you, but GP. just got me going with his analogy to the race motor and I couldn’t help myself.
Below is a photo of one of my (our teams, I did the motors) biggest DIY projects. We raced through the 80’s across the US and Canada (Raced a few times on Lake Decatur). There are a lot of stories behind this boat (and a lot of overlap as well).
Rodd Yamashita
I'm glad you have a good sense of humor. I didn't want to offend you, but GP. just got me going with his analogy to the race motor and I couldn’t help myself.
Below is a photo of one of my (our teams, I did the motors) biggest DIY projects. We raced through the 80’s across the US and Canada (Raced a few times on Lake Decatur). There are a lot of stories behind this boat (and a lot of overlap as well).
Rodd Yamashita
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CryingDragon
Ouch!
Can't contain my laughter! Fellow co-workers are looking at me strange as I type this but hey...who cares! It's nice to see that I'm not the only one who has felt the evil sting of electrical current. If I named every instance of my "hot sparks a flyin" episodes....well lets just say that I would be typing for a very long time. But I will leave you with this for a chuckle. I still can't turn my guitar amp on with out my pulse starting to rise and my hart fluttering a little...Ouch! Man does 500VDC hurt...more so if you touch the source 3 times in a row. Don't ask.
Rino
Can't contain my laughter! Fellow co-workers are looking at me strange as I type this but hey...who cares! It's nice to see that I'm not the only one who has felt the evil sting of electrical current. If I named every instance of my "hot sparks a flyin" episodes....well lets just say that I would be typing for a very long time. But I will leave you with this for a chuckle. I still can't turn my guitar amp on with out my pulse starting to rise and my hart fluttering a little...Ouch! Man does 500VDC hurt...more so if you touch the source 3 times in a row. Don't ask.
Rino
Worst DIY attempt
About 10 years ago I was having a party,but i didn't have any good speakers ,just awful crappy 25 watt speakers.At this point i didn't know that much about audio.And i had a 50w x2 amp.
So i did the worse possible thing,I borrowed an old guitar amp from my mates audio repair shop.Without the guitar amp.Just a speaker and an old battered chipboard box,and it was open backed.The speaker was a 10 inch fullrange,with no wattage indication whatsoever.
I connected it to one of the channels of my hifi amp,and turned it up loud.But there was hardly no bass,so i closed the back of the cabinet with cushions.But that made it sound quiet,so i kept turning the volume up.At about half volume an awful burning smell came from the speaker,i kept turning it up.Now the amp was on three-quaters and smoke poured from the cloth dustcap.
I turned the amp to full volume as well as boosting the bass,and treble knobs to full.The room filled with smoke,but after about 1 minute of pouring smoke,there was a loud bang,and i saw a huge flame ignite the dustcap area.I wonder why the amp didn't shut off,amp is protected by shorts by a relay,but didn't stop when speaker was blowing up literally.
About 10 years ago I was having a party,but i didn't have any good speakers ,just awful crappy 25 watt speakers.At this point i didn't know that much about audio.And i had a 50w x2 amp.
So i did the worse possible thing,I borrowed an old guitar amp from my mates audio repair shop.Without the guitar amp.Just a speaker and an old battered chipboard box,and it was open backed.The speaker was a 10 inch fullrange,with no wattage indication whatsoever.
I connected it to one of the channels of my hifi amp,and turned it up loud.But there was hardly no bass,so i closed the back of the cabinet with cushions.But that made it sound quiet,so i kept turning the volume up.At about half volume an awful burning smell came from the speaker,i kept turning it up.Now the amp was on three-quaters and smoke poured from the cloth dustcap.
I turned the amp to full volume as well as boosting the bass,and treble knobs to full.The room filled with smoke,but after about 1 minute of pouring smoke,there was a loud bang,and i saw a huge flame ignite the dustcap area.I wonder why the amp didn't shut off,amp is protected by shorts by a relay,but didn't stop when speaker was blowing up literally.
My worst DIY wasn't electronics but involved my first love... Chemistry! When I was 13, I stumbled across a book at the public library showing how to build your own backyard still. I was already into all kinds of experiments , so this seemed a logical branch of the science 
I knew they wouldn't check the book out to me so I copied it for free on site 
I got all my ingredients together and set out for the back of my parent's property. At the time this was the middle of the Arizona desert with only a dozen houses within 5 miles. I made off with my mother's large sun tea jar for the evaporator and an oil lantern for a burner, some coils of copper tubing and various other necessary pieces. After a few hours of set up , my friend Mark, who had just made the requisit 3 mile hike, showed up with three tennis ball can full of "fermentables" raisins, rice, oats...all kinds of crap. We dumped it all in and let it soak and then added a little yeast. After a couple of days of fermination we showed back up to start the distillation stage. I assured him the mold on top wouldn't make it into the finished product. After a few hours of sitting in the hot sun and trying to get the alcohol to cook off, we got bored. My friend had a tennis ball with him so we cut the bottoms out of the tennis ball cans and taped them together to make a tennis ball cannon. The extra oil we were using wouldn't burn fash enough so a quick run to the house turned up some butane light fluid which worked pretty well... that is until we decided to go for the distance record, oversoaked the ball and caught the desert on fire. Six scorched acres later 
, with the help of some local firefighters, we got the fire out. It didn't help any when the lead firefighter asked me in front of my parents whether it was the still or the tennis ball cannon that started the fire. 
I knew they wouldn't check the book out to me so I copied it for free on site I got all my ingredients together and set out for the back of my parent's property. At the time this was the middle of the Arizona desert with only a dozen houses within 5 miles. I made off with my mother's large sun tea jar for the evaporator and an oil lantern for a burner, some coils of copper tubing and various other necessary pieces. After a few hours of set up , my friend Mark, who had just made the requisit 3 mile hike, showed up with three tennis ball can full of "fermentables" raisins, rice, oats...all kinds of crap. We dumped it all in and let it soak and then added a little yeast. After a couple of days of fermination we showed back up to start the distillation stage. I assured him the mold on top wouldn't make it into the finished product. After a few hours of sitting in the hot sun and trying to get the alcohol to cook off, we got bored. My friend had a tennis ball with him so we cut the bottoms out of the tennis ball cans and taped them together to make a tennis ball cannon. The extra oil we were using wouldn't burn fash enough so a quick run to the house turned up some butane light fluid which worked pretty well... that is until we decided to go for the distance record, oversoaked the ball and caught the desert on fire. Six scorched acres later , with the help of some local firefighters, we got the fire out. It didn't help any when the lead firefighter asked me in front of my parents whether it was the still or the tennis ball cannon that started the fire. 
spark gap
In high school were were introduced to transformers one day. A freind and I grabbed a couple tro take home to see how big an arc we could create between a couple of large nails by connecting the thransformers in series. The results were prodigious and impressive. The wonnder is that we survived. This was on a military base in Germany where the mains were 220V!
A couple of days later I heard mention at the dinner table that some important communications gear in the area had been having problems due to some kind of mysterious interferance. The time corresponded closely to when my freiend and I were mucking about with the transformers. We weren't far from the E. German border and the Russians were the usual suspects. My guess is that we had unknowingly reinvented the spark gap transmitter.
In high school were were introduced to transformers one day. A freind and I grabbed a couple tro take home to see how big an arc we could create between a couple of large nails by connecting the thransformers in series. The results were prodigious and impressive. The wonnder is that we survived. This was on a military base in Germany where the mains were 220V!
A couple of days later I heard mention at the dinner table that some important communications gear in the area had been having problems due to some kind of mysterious interferance. The time corresponded closely to when my freiend and I were mucking about with the transformers. We weren't far from the E. German border and the Russians were the usual suspects. My guess is that we had unknowingly reinvented the spark gap transmitter.
Update, my new worst DIY thing just happened last week. It involves pulsed power, a hobby which has temporarily taken the place of my audio project(s). This incident, as it was occuring, caused a severe brown out, which made the lights go completely dark, shut off the computer, and reset a few clocks.
I have a large capacitor bank and homebrew solenoid-triggered switch that I use to do cool stuff, like shrinking coins, etc.
I was going to crimp a copper pipe with electromagnetic force, similar to coin shrinking, I had everything set up, ready to go. So I pulled the string to charge the capacitors up (in this case, to about 7000V, 3750J). In a few seconds, when the capacitors were at about 800V, there was some fierce sparking from the charging supply, and a huge cloud of pungent smoke billowed up. I immediately stopped the charger. I had to be somewhere at the time, so I couldn't stick around to see what happened.
A couple hours later, when I got home and looked for the problem, I was amazed to find the wires that go to the solenoid circuit almost completely melted (the insulation made all the smoke, the smell of which was still strong in the air), even melted and fused together, and the solenoid was burned out.
The solenoid is usually powered by a 4800uF capacitor charged to line voltage, switched by a relay. It appears that in this case, line power somehow got the the solenoid, making it draw huge current (It's on a 50A line) to destroy itself and it's wires. But the main capacitor bank still had an 800V charge in it (so the solenoid must not have actuated, or it would have dumped) and the solenoid cap had a full charge in it too.
Or perhaps, if line power somehow got to the solenoid, maybe the "fire" string got accidently pulled or something (though I highly doubt it, it seemed fine afterward), it did actuate, making the charging circuit drive into essentially a direct short. Then when the solenoid burned out, it could have released, allowing the bank to aquire the 800V charge before I turned it off.
So I still don't really know what happened, but I will get a new solenoid and hope it doesn't happen again.
I have a large capacitor bank and homebrew solenoid-triggered switch that I use to do cool stuff, like shrinking coins, etc.
I was going to crimp a copper pipe with electromagnetic force, similar to coin shrinking, I had everything set up, ready to go. So I pulled the string to charge the capacitors up (in this case, to about 7000V, 3750J). In a few seconds, when the capacitors were at about 800V, there was some fierce sparking from the charging supply, and a huge cloud of pungent smoke billowed up. I immediately stopped the charger. I had to be somewhere at the time, so I couldn't stick around to see what happened. A couple hours later, when I got home and looked for the problem, I was amazed to find the wires that go to the solenoid circuit almost completely melted (the insulation made all the smoke, the smell of which was still strong in the air), even melted and fused together, and the solenoid was burned out.
The solenoid is usually powered by a 4800uF capacitor charged to line voltage, switched by a relay. It appears that in this case, line power somehow got the the solenoid, making it draw huge current (It's on a 50A line) to destroy itself and it's wires. But the main capacitor bank still had an 800V charge in it (so the solenoid must not have actuated, or it would have dumped) and the solenoid cap had a full charge in it too.
Or perhaps, if line power somehow got to the solenoid, maybe the "fire" string got accidently pulled or something (though I highly doubt it, it seemed fine afterward), it did actuate, making the charging circuit drive into essentially a direct short. Then when the solenoid burned out, it could have released, allowing the bank to aquire the 800V charge before I turned it off.
So I still don't really know what happened, but I will get a new solenoid and hope it doesn't happen again.
I've had my share of goodness with electronics/electricity.
1) When I was four or five, I was out in the snow helping my dad put on the christmas lights. 'Twas great fun, running around with all the nicely lit strings of lights, and handing to him up on the ladder as he stapled them to the house. Unfortunately, I tripped while bringing one to him, and fell on top of it. Somehow, the glass broke, *and* I managed to get my finger inside the remnants of the bulb, which gave me a nice taste of 120VAC for a fair bit. I can remember being on the ground and being zapped with my muscles all tense for at least five seconds or so. Of course, I got yelled at for breaking the lights, too.
2) I spent a good part of my adolescence blowing things up and setting them on fire. Seeing as hydrogen is a fun material to have for such things, one of my best friends and I decided to make an electrolysis apparatus. We dutifully made a low voltage DC supply, threw some water and salt into a large bucket, and used some old beer bottles to collect the gases from each electrode. While this did produce some hydrogen, it wasn't anywhere near fast enough for our liking. We decided to take an old extension cord, strip the wires, and stick them into opposite ends of the bucket. We added enough salt to the water to saturate the solution, put a garbage bag over the large bucket, and plugged the cord in. We were happy to see furious bubbling happening at each electrode - FINALLY we were getting somewhere!
Unfortunately, the reaction apparently liberated a lot of elemental sodium, which ate through the wires in a hurry. We had the wires coiled around in the bottom and had at least 3 feet of each in the water. By the time we were done, there wasn't any copper left.
More disturbingly, the reaction produced large quantities of chlorine gas, which promptly filled my friend's garage. Our first reaction was "man, this smells like the swimming pool's chemical room", followed by "I don't feel too good", later followed by severe coughing and pulmonary distress.
I have a much healthier respect for chlorine now. That experiment wasn't terribly pleasant.
3) On a similar note, much fun can be had by filling large (100+ liter) garbage bags with natural gas from the bleeder valve on the gas main at the side of your house. They make nice (large) fireballs when you tie them shut with some string soaked in gasoline, and let them fly up in the air and light the string.
I've never been hurt by doing this, but have set numerous trees and bushes on fire. The melting plastic from the remnants of the plastic bag make really cool whistling noises as they fall to earth as well - reminiscent of the hindenburg, actually.
4) I spent many of my formative years repairing PCs for people, and collect a lot of the little 3" PC speakers over time. They're fun to connect to the 120V mains.
5) Like many of you, I got the idea that "if a small electromagnet, is good, a bigger one must be better", and have plugged my fair share of copper coils into the wall socket.
6) My worst DIY effort would have to be my Extended-reach remote illumination actuator (tm), however.
It consisted of some 1" wooden dowels electrical taped together so I could reach the light switch (which is across the room) so that when I was done reading in bed, I could just poke the switch with the long rod, roll over, and go to sleep.
Unfortunately, I ended up knocking out the support for one side of the hutch on my computer desk, which was jury-rigged in order to fit my large monitor underneath it. Knocked over 2 spindles of 50 blank cd's, 2 speakers (both smashed), a hub, some other miscellaneous stuff, and took a chunk out of my monitor casing as well.
There wasn't much I could do except shake my head and laugh at my own stupidity, roll over, and go to sleep.
I'd like to say that'd be the last time I was *that* lazy, but realistically, I know that'd be a lie.
1) When I was four or five, I was out in the snow helping my dad put on the christmas lights. 'Twas great fun, running around with all the nicely lit strings of lights, and handing to him up on the ladder as he stapled them to the house. Unfortunately, I tripped while bringing one to him, and fell on top of it. Somehow, the glass broke, *and* I managed to get my finger inside the remnants of the bulb, which gave me a nice taste of 120VAC for a fair bit. I can remember being on the ground and being zapped with my muscles all tense for at least five seconds or so. Of course, I got yelled at for breaking the lights, too.
2) I spent a good part of my adolescence blowing things up and setting them on fire. Seeing as hydrogen is a fun material to have for such things, one of my best friends and I decided to make an electrolysis apparatus. We dutifully made a low voltage DC supply, threw some water and salt into a large bucket, and used some old beer bottles to collect the gases from each electrode. While this did produce some hydrogen, it wasn't anywhere near fast enough for our liking. We decided to take an old extension cord, strip the wires, and stick them into opposite ends of the bucket. We added enough salt to the water to saturate the solution, put a garbage bag over the large bucket, and plugged the cord in. We were happy to see furious bubbling happening at each electrode - FINALLY we were getting somewhere!
Unfortunately, the reaction apparently liberated a lot of elemental sodium, which ate through the wires in a hurry. We had the wires coiled around in the bottom and had at least 3 feet of each in the water. By the time we were done, there wasn't any copper left.
More disturbingly, the reaction produced large quantities of chlorine gas, which promptly filled my friend's garage. Our first reaction was "man, this smells like the swimming pool's chemical room", followed by "I don't feel too good", later followed by severe coughing and pulmonary distress.
I have a much healthier respect for chlorine now. That experiment wasn't terribly pleasant.
3) On a similar note, much fun can be had by filling large (100+ liter) garbage bags with natural gas from the bleeder valve on the gas main at the side of your house. They make nice (large) fireballs when you tie them shut with some string soaked in gasoline, and let them fly up in the air and light the string.
I've never been hurt by doing this, but have set numerous trees and bushes on fire. The melting plastic from the remnants of the plastic bag make really cool whistling noises as they fall to earth as well - reminiscent of the hindenburg, actually.
4) I spent many of my formative years repairing PCs for people, and collect a lot of the little 3" PC speakers over time. They're fun to connect to the 120V mains.
5) Like many of you, I got the idea that "if a small electromagnet, is good, a bigger one must be better", and have plugged my fair share of copper coils into the wall socket.
6) My worst DIY effort would have to be my Extended-reach remote illumination actuator (tm), however.
It consisted of some 1" wooden dowels electrical taped together so I could reach the light switch (which is across the room) so that when I was done reading in bed, I could just poke the switch with the long rod, roll over, and go to sleep.
Unfortunately, I ended up knocking out the support for one side of the hutch on my computer desk, which was jury-rigged in order to fit my large monitor underneath it. Knocked over 2 spindles of 50 blank cd's, 2 speakers (both smashed), a hub, some other miscellaneous stuff, and took a chunk out of my monitor casing as well.
There wasn't much I could do except shake my head and laugh at my own stupidity, roll over, and go to sleep.
I'd like to say that'd be the last time I was *that* lazy, but realistically, I know that'd be a lie.
I made a DC-DC powersupply using linear regulators to run a computer in the car.... I had been using it to run a P100 in teh house (getting 12volts from an AC-DC powersupply, being used as the battery would be) and wondered if it had enough power to run my celeron 400.... I plugged it into the motherboard, and HD, grabbed the power cable and plugged it into the DC-DC powersupply... too bad it was the AC CORD!!! @ 240volts!!! well, the computer didn't last, the powersupply didn't last, the house fuse didn't last... serves me right for using a mains socket for low voltage!!!! ohh well, Not going to do that again in a hurry... it was just last year.. I was 15 at teh time.. lol
You know those gas stoves with the electric igniter that arcs accross a small gap... not the ones that just spark once, but teh continuous arcs... well, don't stick a piece of wire in one of those...
OHHH!!! I wired a bridge rectifier to the mains, with a fluro tube on the DC output... well the bridge went up with a pop and a spark, all the lights in the house dimmed, and a fuse blew..
ANOTHER!!!
I was trying to make an amplifier using a LM3886 amplifier.... I wired up the circuit without a PCB, plugged the transformer to teh mains... switched it on... and... BANG!!! I think I connected the filter cap around the wrong way... Hmm, thats about it... all in about 1 year too..
lolYou know those gas stoves with the electric igniter that arcs accross a small gap... not the ones that just spark once, but teh continuous arcs... well, don't stick a piece of wire in one of those...
OHHH!!! I wired a bridge rectifier to the mains, with a fluro tube on the DC output... well the bridge went up with a pop and a spark, all the lights in the house dimmed, and a fuse blew..
ANOTHER!!!
I was trying to make an amplifier using a LM3886 amplifier.... I wired up the circuit without a PCB, plugged the transformer to teh mains... switched it on... and... BANG!!! I think I connected the filter cap around the wrong way... Hmm, thats about it... all in about 1 year too..
At about 40+VDC, a 3" 12VDC muffin fan will lift off the table... for about 3 seconds
While attempting to measure the output voltage of a mystery transformer in a friend's amp, I managed to short the transformer.... He can't solder to save his life, and the leads on the bridge were almost touching. The light in the shop was too dim to see that, and I managed to push the leads together *just* enough (about .03 inch) to touch. At least the only damage was a tripped mains breaker and a "WTF" from my brother in the other room, who just lost the power to his TV.
Mark Broker
While attempting to measure the output voltage of a mystery transformer in a friend's amp, I managed to short the transformer.... He can't solder to save his life, and the leads on the bridge were almost touching. The light in the shop was too dim to see that, and I managed to push the leads together *just* enough (about .03 inch) to touch. At least the only damage was a tripped mains breaker and a "WTF" from my brother in the other room, who just lost the power to his TV.
Mark Broker
My computer broke so a little surgery fixed it (not the bad part, that worked out fine). After typing six hours of homework on it and not saving it crashed. I went insane on it and now it's in pieces. The steel chasis is all bent out of shape, I kicked it, stomped on it, beat it with it's own side, smashed it against the wall and threw it on the floor. The lesson I learned from this is that I'm going to buy a mac...
Now now, be nice. Everyone gets frustrated now and then.
All computers crash, even Macs. If you're going to buy one, make damn well sure you get one with one of the flavors of OS X on it, or its stability will likely be inferior to any recent PC with an NT based (NT, 2000, XP) operating system on it.
Having said that, the newer macs that actually have a good operating system on them (OS X) are excellent, albeit expensive and with a severely limited software base. To each his/her own, though.
ThingyNess said:
To address these in reverse order...
In some areas the Mac has a limited software base (unforuneatly electronics and speaker software is among those), but in other areas the tables are turned. In graphics and publishing for instance the Mac is way ahead -- even programs that are cross-platform work better & more seemlessly on the Mac -- due to the elegance of the underlying OS. And those areas where the selection of software isn't so rich... well with OS X we are seeing an aweful lot of exotic software ported from UNIX. (and there is always Virtual PC -- running on a Mac still doesn't make Windows any less ugly)
For the last 18 months or so, every new Mac shipped with OS 9.x and OS X (and althou X was the default you could boot into 9). Starting in Jan they will only boot X (but most older aps can still be run in Classic).
And yes the Macs crash. An aweful lot less in X (i push mine over the edge once every month or so), but aps still crash inside X, so one still needs to have that command-S reflex (i don't know how many times that has saved my butt).
dave
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The most stupid,and frightning project i ever made was powering a 120v cooling fan with 240v ac.
I found a really crappy cooling fan in a skip,outside my colledge.
It was rated 120v dc,i think it was from a computer psu or something simular.
When i got home,i connected it with a plug attached to two wires to the postive and negative on the fan.Positioned it away from the carpet,infact i put it on a metal tray[stupidly].When i switched it on,it spun too fast,and smelt of burning plastic.After about 30 seconds,smoke poured from it and it suddenly went dead.
I went to see what happened,and as i touched the meatal tray,i got a nasty shock.It made my fingers go very numb,luckely the RCD on the comsumer had just tripped out ,otherwise i'd probably be dead.But those slow RCD's and circuit breakers,take their time to trip,unless you directly short two pieces of wire together[then they trip in about 1 second].It took about 2 mins for the RCD to trip,too long,and now i've got permenant scars on my fingers.Now i've learnt,i can't even trust RCD's,not even the plug in type.At least they are quicker than fuses that take about 5----15 mins to blow.
The most stupid,and frightning project i ever made was powering a 120v cooling fan with 240v ac.
I found a really crappy cooling fan in a skip,outside my colledge.
It was rated 120v dc,i think it was from a computer psu or something simular.
When i got home,i connected it with a plug attached to two wires to the postive and negative on the fan.Positioned it away from the carpet,infact i put it on a metal tray[stupidly].When i switched it on,it spun too fast,and smelt of burning plastic.After about 30 seconds,smoke poured from it and it suddenly went dead.
I went to see what happened,and as i touched the meatal tray,i got a nasty shock.It made my fingers go very numb,luckely the RCD on the comsumer had just tripped out ,otherwise i'd probably be dead.But those slow RCD's and circuit breakers,take their time to trip,unless you directly short two pieces of wire together[then they trip in about 1 second].It took about 2 mins for the RCD to trip,too long,and now i've got permenant scars on my fingers.Now i've learnt,i can't even trust RCD's,not even the plug in type.At least they are quicker than fuses that take about 5----15 mins to blow.
ThingyNess said:
When I went to apply for a patent for MY design, I learned someone had stolen my idea and already (tm)'d it!!! I was you! You big thief...
I had my room rigged up with little eyelet hooks and a lot of string. I pulled one string to turn the lights off, and one to turn them on. Worked like a charm.
I was 7 years old. My IR and RF skills were not quite up to snuff so I had to go with the remote control skills that I had.
My next project will be a remote on/off, vol up/down for my amp. I have allready started collecting the parts: eyelet hooks...check. ball of twine...check. tape...check.
Not DIY but a nice one. When I went to school I had to work one year at three different companies to learn the practical things of electronics.
I worked at a company that made very big DC power supplies for machines that are used to zinc coat cars.
One day my chief suggested we could do a test run on the newest supply. We would do a temperature measurement at full load. When we were running 2000 Amps at 5V in a very big resistor bank the chief suddenly yelled at me that he had forgotten his new fluke inside the supply which ran very hot at 2000 A
I asked him ( eager to help ) if I had to shut down the supply. He immediately ordered me to do so. Which I did, I pushed the mains breaker and it stopped. Well, every semiconductor stopped in fact. The chief's face got very red
and he said that the meaning was to slowly adjust the current to zero and that stopping the supply in one second had blown all thyristors, fuses and electronics in it ...
I never realised the power of electricity before that. We made coils of copper bar that had only one turn ( ! ) . Running at 2000 A the iron doors of the case became hot of the magnetic field this one turn coil created !
I worked at a company that made very big DC power supplies for machines that are used to zinc coat cars.
One day my chief suggested we could do a test run on the newest supply. We would do a temperature measurement at full load. When we were running 2000 Amps at 5V in a very big resistor bank the chief suddenly yelled at me that he had forgotten his new fluke inside the supply which ran very hot at 2000 A
I asked him ( eager to help ) if I had to shut down the supply. He immediately ordered me to do so. Which I did, I pushed the mains breaker and it stopped. Well, every semiconductor stopped in fact. The chief's face got very red
and he said that the meaning was to slowly adjust the current to zero and that stopping the supply in one second had blown all thyristors, fuses and electronics in it ...I never realised the power of electricity before that. We made coils of copper bar that had only one turn ( ! ) . Running at 2000 A the iron doors of the case became hot of the magnetic field this one turn coil created !
If your RCD takes more than 30 ms (0.03s) to break have it replaced !!!!! And if your fuses take 5 to 15 mins to blow I will not say you have a short it must be an overload maybe 1.2 times (guess) the Amp rating on fuse. If you have a real short we are talking maybe 5 ms for a fuse to blow.
A fuse can NEVER protect you from dangerus currents. And a RCD will NOT protect you if you touch live and neutral.If you want to continue playing around with the mains I strongly suggest you learn more about it. search the net there are lot of stuff about this out there.
Keld (tripped a RCD once throug my arms. Ouch)
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