My first zap, Ouch, that hurt.

[mgordon99]

I was putting one of those flimsy metal slot covers on the back of my PC, the ones that cover the holes of empty card slots.

Some how the metal piece came in contact with the NIC, and zap! I was hit with a good jolt. My PC was off too. That was my first zap since I have fiddled with PC's (3 years).

[SysOpt]

Yeah, some cards have components on them that can pack quite a punch. I had a 56k modem a couple years ago that I tried to remove just after turning the power off, put my thumb and forefinger on the card, and ZAP - did not feel pleasant. Ended up doing it several other times trying to remove that card. I no longer use it, thankfully http://sysopt.earthweb.com/forum/wink.gif.

[grunt]

Been shocked twice in 4 yrs - once by a NIC and once by an ATI All in Wonder.

[jman01pa]

Its not that bad. What would you rather have a shock or a case cut across 4 fingers. Yep I did it today. Cheap case. Not mine I was just working on it. Blead like a stuck pig too.

J http://sysopt.earthweb.com/forum/smile.gif

[KillerBug]

PLAYSTATION!!!

Power supply just like a computer, inside, except it is not in its own metal case, it is out in the open, I only have 9 fingerprints now.

[voogru]

I got Shocked only once in 7 years (from 6 years to 13) well i putin my new 330 watt power supply and pushed the power button it was not grounded (ZZAP!!!!!!) a nice 120 volts of power into my right arm I didnt fell it for a few days

voogru
(dont forget to ground the switch!)

[jjsole]

A few years ago, I got a nice shock pulling a modem card out when the computer was plugged in (and turned on - oops). I think the shock affected my short-term memory somehow. Well, to make a long story short


I'm sorry, where was I?...

[Jeff7]

Got a few shocks from a modem, before it finally occurred to me to disconnect the phone line. I also did test the phone line with a VOM - I think it was something over 60volts.
Let's see, also got 100,000 volts too. Several times in fact. Never felt a thing either. Tesla coils can be much fun to play with. Dangerous though if you dont know what you're doing. Oh well; here's a link to build one, if interested:
http://jeffelec.tripod.com/tesla/tesla.html

[This message has been edited by Jeff7 (edited 07-21-2000).]

[falcompsx]

LOL, well looks like i'm not quite as stupid as i thought i was(I am still quite stupid at time though). Anyway, when i was a kid, I was really stuipd, i used to stick stuff in outlets and get shocked repeatedly(maybe that's where my brain cells went). My parents did use those covers on the outlets, but i was just smart enough to get them off, and dumb enough to put my finger or knife or something in. More recently, I was really stupid, thinking that turning off the switch on an AT powersupply would eliminate risk...so i got some needle nose pliers(metal of course) and needed to remove th econnectors off the swithc on to a rocker switch. easy enough...still plugged in...well the rubber guard slipped, and the pliers hit the hot one and the case at the same time...with me inbetween. enough said i think...

[Ultima]

There was only 1 time that I got zapped.

I was gonna re install win98, and was getting all the cards out except for the video ofcourse.

Pulled out my nic card, which accidently touched something and got a shock.
I had a little shock, I'd survive, but unfortunately my nic didn't.

Pim

[nilknarf]

Not to offend, but some of you do stupid things with electricity.

That's OK! I've had my share of zaps from live AC lines and elecronics that were supposed to be off. Guess I could be a little more careful too!

Just remember, even when they're disconnected from power, electronics can still pack a punch. They have these little components called capacitors, which are just like a battery in that they store energy. Just they store it at a voltage which typically can zap you pretty good. I've melted screwdrivers while shorting capacitors in order to discharge them. Of course those were much bigger than what you find in most home electronics, but the principle is still the same.

Okay, lecture over, you kids go have fun, just be careful.

My 2 cents.
Tim

[This message has been edited by nilknarf (edited 07-20-2000).]

[Britewood]

Hehe

I was pulling out a sound card once the machine was off an I was grounded. Well the sound card was under the modem and when I went to disconect the audio cable to the CD-Rom the phone rang. Nuttin more interesting than a pulsating shock from your modem ringing your fingers. hehehe. Needless to say I disconnect my modem from the wall when I work on my boxes!

Britewood

[flash4master]

i havent been shocked...yet, well not a major shock anyway. i had a phone that was open adn plugged in, i was messin around inside of it when someone decided it was time to call.....

[jad1097]

nilknarf I am glad to see I am not the only one who thought these people seem to be careless with eletricty. I have melted many screwdrivers/tools in the past.

I have yet to be shocked from my computer because I am carful. I have been schocked many times being an eletrican but I have not even been shocked at work in more than 5 years that I can recall because I am careful.

[alpha]

Ouch! I got a shock of a monitor VGA cable and, somewhat worse, 220volts from a psu switch missing insulation. Hand stuck to the switch for a few seconds and I couldn't feel it for ages.

[El_Brio]

You have to watch out for those capacitors. Big ones can pack a real punch hours later. Big capicitors from camera flashes or t.v.'s can actually deal out a lethal shock!

[Missing the point]

I don't know what voltage this was, but it was an old 386, with the 4 prong power switches. I had recently taken it out, and put it back in, and I tried to boot it up, but nothing happened. I was kinda puzzled, so I looked, and the WHITE wire was off. Ok, so I put it back on. ZZZZZZZZAAAAAAAAPPPPPPPPPPPPPPPPPPPPP!!!!! HUGE white spark went all the way up my arm, and burnt off all the hairs on its way. I had forgotten to turn the power supply off :P

Now you can tell me how dumb I am http://sysopt.earthweb.com/forum/smile.gif

[Jeff7]

Well, that sounds like it must have been fun. You mentioned a power supply, which brings up another point - voltage doesn't kill - amperage does. See my previous post about the 100,000 volt Tesla coil - you just hold a metal rod in one hand, and a flourescent light in the other, and then let the 3-inch sparks hit the metal rod. The flourescent tube will light up, and you won't feel a thing. Thing with that is this: extremely low amperage, and very high frequency.
Power supplies have low voltage, but they pack a LOT of amps. And, the frequency is very low - 60Hz in the wall, or 0Hz in the power supply - DC current. Low frequency, high amperage power of any voltage is dangerous.

[krusty the klown]

You have hit on two very good points there Jeff - both current and frequency are very important.

The current that actually passes through your body is the factor that determines the severity of the shock, but voltage, resistance and frequency determine how much current passes through your body.

When medical staff defibrilate a patient that has suffered a cardiac arrest, the 'paddles' that they put on your chest are large and they also use electrically conductive gel. This reduces the resistance of your chest to around 50ohms, allowing a large current to pass through your body. It it necessary to pass such a high current so that the current that passes through your heart is sufficient enough to momentarily stop it and allow it to restart (ventricular fibrilation - VF - is where the cells in the heart muscle are out of step and the shock stops the heart totally, so hopefully, it restarts in step). It you were to have a live wire gently touch the surface of your skin and your skin was dry, the resistance between the wire and ground may be kilohms to megohms, so only a low current passes.

To look at the body from a purely resistive view is fime for DC and low frequency AC, but as the frequency increases, your body firstly becomes more susceptible to current, then as the frequency gets very large, your body becomes very tolerant to electricity. This is due to impedance effects - your body is made of of cells, which can be thought of as containing a resistance and a capacitance (the cell fluid and the cell membrane). It is this impedance that renders high frequency currents less harmful than low frequency currents.

Ironically, your body is most susceptible to 50-60Hz!

EDIT: Grrrr typos http://sysopt.earthweb.com/forum/redface.gif


[This message has been edited by krusty the klown (edited 07-21-2000).]

[krusty the klown]

Jeff, ur link doesn't seem to work - I'd be interested to read the info on Tesla coils, if it's still there!

[CMonster]

Got a mild stimulation there eh? Now you know you are alive! hehe..

17+ years experience as an equipment mechanic - secondary ignition systems have tought me quite a bit about the merits of electro ~Zap!~ convulsive therapy http://sysopt.earthweb.com/forum/smile.gif I've been hit repeatedly by 10-40KV (!yeah like almost no amps but enough to wake my 4$$ up!) - not to mention a few 110 and 220AC jolts over my lifetime - the worst being when I was 12-years old and grabed a 220v fuse with each hand - thinking that the power was off in this demolished industrial site - thank God I wound up on my **** about 10ft away...!!

[tonym]

I think I'll pull out my periodic reminder about working with power and electronic circuits.

A list of no-no's:

1. Never work on a piece of energized equipment when you're sweating, for any reason. Sweat illicits salt to precipitate on your skin and you become VERY conductive and most prone to shock when you sweat.

2. Always remove any jewelry (weddings rings and pendulous neckaces/medals). I have personally seen a co-worker almost cauterize their wedding finger OFF when high current passed through their wedding ring.

3. Always remove the phone jack from your PC whilst working on it. It's a very unpleasant 110V ring signal that you really don't want to come in contact with!

4. Use isolated tools whenever possible.

5. Always de-energize capacitors (see Tims reply). You can touch a 100 Ohm resistor across the cap to bleed away charge -- just make sure you're isolated from the connections.

6. The worst (catastrophic) shock that you will endure is an arm-to-arm or an arm-to-leg. The current has to pass through your chest in the unintenional circuit of which you're a part, and you can damage/stop the heart mucscle. When in doubt, put your hands in your POCKETS and keep your **** NOSE away from the power (head-leg or head-arm are just as bad).

7. You don't need to come directly into contact with AC power to get a shock. If you get close to an UNINSULATED conductor (without touching), you can capacitively couple the shock current through your body. Proximity kills!

8. Always double check if the power is OFF! Most folks never get into a routine when dealing with power becasue they do it so infrequently. Get into the double check habit. Most shocks happen when the person gets tired or careless. You wouldn't get careless handling rattlesnakes -- power is JUST as dangerous!

9. Finally, don't forget the "R" word. R-E-S-P-E-C-T! Familiarity always breeds contempt, and it's human nature to trivialize something that's never hurt us in the past. So why would it in the future?? The bottom line is you can NEVER be too cautious!

I know, these cautions are common-sense obvious. But I've seen so many people forget the basics and get hurt because of it. I don't want that to happen to you!

Have fun...


Tony

[nilknarf]

Tony, you wouldn't happen to know this stuff from experience, would you?

Good advice though.

Even when you checked and double checked, there is still the potential for residual charge on the circuit. Especially in electronics and computers.

And yes, phone lines do carry a charge. I think it's something like 48V. Got to power your fancy phones somehow.

Better watch out for those monitor connections. CRT's of any type carry very high voltage inside. Even when they are off they may still have a charge. We're talking thousands of volts.

Current kills, not voltage. AC will kill faster than DC. But, you can still get enough current off a 9V DC battery to kill. Maybe you'll think of this next time you decide to test a 9V battery with your tongue!

Tim

[Jeff7]

There, Tesla page link is working now; here it is again though:
http://jeffelec.tripod.com/tesla/tesla.html

Apologies in advance for the pop-up ads, too; perhaps I'll have to get the premium service for whatever $$$ a month to get rid of them.

[This message has been edited by Jeff7 (edited 07-21-2000).]

[jad1097]

Yes some very good advice Tony. I also believe that a phone line while ringing only delivers 40-50volts DC.

1/10th of an amp will kill you if you are hit just right.

Some of the worst hits I have had are off a distributor on a car, I thought all the wires were on it when to adjust the timing and it threw my *****. Another of the worst was getting hit by a neutral on a 277V florescent ballast. That sucker grabbed me for what felt like forever. Someone ended up knocking the ladder from under me.


It just eats me up to see some of my brothers wearing jewelry to work and then insist on working things hot! 4 years of school (5 now) and they still do it even though they know better.

#1 is not always possible for me since it is sometimes unavoidable. But for the average person it is. The main thing to be sure of is that you are not grounded.

And I really don't care to mention how many times I have been told "don't worry the circuit is off" and it still be hot!

CMonster now that is funny!
Kids don't try this at home!! I used to work with a guy who would test circuits with his fingers(same hand). He would first lick them and then touch one finger to ground and the other on the wire in question.


If you ever see someone getting shocked do not touch them or grab them no matter what you do! Break them loose with a non-conductive object such as a 2X4 or if they are on a ladder knock if from under them. Yes I have had to do both.


I have known several people who have died due to carelessness! Please be careful.

[This message has been edited by jad1097 (edited 07-21-2000).]

[diesel]

got my first zap from a modem when trying to remove it. got my second when trying to tighten an AT psu switch while plugged in. It had a rubber gaurd over it but it slipped and the end of the screwdriver melted off... not fun

[El_Brio]

Well, no one will probabaly believe this but here is my electrocution story.

I was like 16 and I found a cool old lamp at a garage sale. I brought it and discovered that it needed a new cord. So I plugged in a different lamo to make sure it worked. Then I cut the working cord and was going to splice it into the new lamp. Well I have a bad habit of using my teeth to strip wires. I stripped one of the leads and then I popped the other lead into my mouth ---at the same time--- to strip it. ZAP!! I got a real jolt, but not near as bad as I thought it would have been. Considering that I had both ends of a wall plug in my mouth at the same time I think I was lucky. If I was grounded I probably would have died. Moral of the story- don't strip wires with your teeth and NEVER work on something without checking to make sure that its unplugged.

[Mykex]

ok Ill add my worst zap to this.....A rainy day hole in my boot welding 1/2" plate on a grounded table "feet up on table leg brace" all that was left was the cover to be missing where you tighten the screw to hold the cable in place ... a perfect circut me in the middle. Long story short thrown 6'against cinderblock wall 2 nastey burns and a mild concusion. Funney havent done much welding since. LOL