I am mostly interested in the longterm physiological effects. Here is an example of an unusual longterm issue:
http://ecmweb.com/mag/electric_happens_electricity_doesnt/index.html
I’ve had a few electric shocks in my life, but as far as I know I don’t have any serious long term effects.
One time I got shocked stepping onto a soviet trolley bus – I passed out almost immediately and the only long term effect I can think of is fear of trolleys. I was lucky it was foot-to-foot (one foot was on a metal step, another in the snow) because those things run on close to 400V AC.
When I was a kid growing up in Oklahoma the father of a classmate of mine drilled and repaired water wells and windmills. One day my classmate and his brothers were on the job with his dad and were hanging on the back of a gin truck when his dad backed into a power line. His brother died, and he was severely hurt, and required skin grafts.
I have an uncle who accidentally grabbed a high voltage line. His muscles froze and the man working with him probably saved his life by hitting his arm with a 2x4 and knocking him loose. I remember him with his left hand sewn to his back while he was healing. After healing completely, his left arm was permanently bent at the elbow at about 90° and his hand looked kind of like a big crab claw.
I know lots of people, myself included, who’ve received shocks at the low voltages described in the article but no one with those types of effects.
Although it would explain a few things about some people.
As someone that has worked with electricity and electronics most of my adult life, I have been zapped pretty good a number of times. The worst was a large capacitor that I did not discharge before reaching into an HF transmitter. I suffered a burn to my hand from the shock, a concussion when I slammed into the wall behind me and 2 broken ribs from my co-worker hitting me in the chest to start my heart. It only took a few weeks to get over the effects of the shock and a couple months to recover from the other injuries.
I now work on live aircraft in a factory setting. I use all the safety procedures that are in place and rarely get shocked. The real problem with airplanes is they operate on 400 cycles instead of 60 cycle AC voltage so the kick is a bit stronger. I couldn’t imagine going through what the guy in the link is going through.
The Professor of EE who performed the study detailed in the link provided, while well motivated has way too much faith in his results. An uncontrolled, retrospective study with self-reporting as the basis for data acquisition (with patient recruitment from the Internet and all its inherent liabilities) would probably not even be reviewed, let alone published, by any reputable medical journal.
Electricity does bad things to you generally in one of two ways.
The first bad thing is that it can screw up your heartbeat. Your heart can go into a state called fibrillation where instead of beating it just sits there and shakes, and the funny thing about your heart is that this fibrillation state is stable, meaning that once you get it into fibrillation it tends to stay there. Unless someone is standing next to you with a portable defibrillator, you could be in very deep doo-doo (and actually I’ve heard that even if you do have a portable defibrillator handy that the chances of restoring a normal heart rhythm are surprisingly small - it’s not like TV where the patient always comes back after getting whacked with the paddles).
A very small amount of electrical current can potentially throw your heart into fibrillation. Currents so small that you can barely feel them are more than sufficient. The thing is, this sort of thing is very hit and miss. People get low level shocks like this through their chest all the time and their heartbeat doesn’t go wonky. Your heart is also funny in that it is much more sensitive to getting thrown out of whack at certain times during its rhythm than others, so even under exactly identical circumstances there is still some randomness to it just based on where your heart happens to be in its rhythm at the time. It is currently thought that shocks below about 5 mA are “safe”, though for obvious reasons there hasn’t been a lot of human testing done on this subject. Generally speaking, the more current you get flowing through your chest the more likely it is that you’ll throw your heart into fibrillation, and the frequency of the electricity also matters. It turns out that right around 50 or 60 Hz are the frequencies most likely to throw the heart into fibrillation, so from a safety standpoint we almost couldn’t have chosen worse frequencies to use for power systems.
Another funny thing is that as you increase the current, the risk of fibrillation also increases, but only to a point. Once you get above a certain current level, instead of going into fibrillation the heart is much more likely to just have all of its muscles contract and stay there. This still isn’t a good thing, since the heart isn’t pumping blood, but once you remove the source of the current in this case the heart will usually go back to a normal rhythm. It’s therefore a little counter-intuitive that larger shocks are actually less likely to kill you.
These types of shocks are generally so low in current that the current itself doesn’t cause you any harm. However, when your heart is in fibrillation it’s not pumping blood, so you can get all sorts of bad things that result from the lack of oxygen flowing to your cells. Permanent brain damage and all sorts of other effects are possible.
The second type of damage that electricity does to you is that it cooks you, quite literally. This happens at much higher current levels than the types of shocks that cause fibrillation, but this type of damage is much more guaranteed and isn’t hit or miss like fibrillation is. When electrical current flows through something, and that something resists the flow of electricity (which all things except superconductors do) then some of the electrical energy is converted into heat. The classical example of this is if you remove a lamp cord from a lamp and take the bare wires on the end and attack them to nails, then you stick the nails into a hot dog and plug the cord in, you’ll cook the hot dog very quickly (typically in under a minute). By the way kids, don’t try this at home because we electrical folks call cords with bare wires on the ends “suicide cords”, for good reason. Anyway, if you get a large amount of current flowing through part of your body you can end up getting cooked just as easily as that hot dog. This in fact is how the electric chair works. It literally cooks its victim to death. The theory is that the brain is so badly damaged in the first instant of the shock that the victim isn’t conscious of the rest of their body being cooked for the rest of their time in the chair.
Burns from lightning, high voltage lines, etc. can definitely result in permanent, long term damage. People have lost limbs, suffered permanent brain damage, nerve damage, and all other sorts of effects from the burns.
While permanent damage can occur, most folks who get shocked do not suffer any long term effects. There have even been some folks who have walked away from lightning strikes without any permanent damage.
One of the lighting guys on a film set I worked on got a bad zap. I’m not totally sure what happened. The guy was standing on an A-frame ladder (wood, I think) with a light in his hand that he was supposed to attach to a suspended pipe. I heard a -POW!- but I can’t say if what I heard was the zap or just the sound of the guy flying off the ladder. Basically, I’m useless as a witness.
In any case, he went flying like Superman, but sideways, and hit the wall I was putting up which fell over. AFAIK, the guy was fine with no long-term effects. He went to the hospital and was off work for a few days. I don’t remember if he had burns or anything, but he definitely had bruises (at least from flying off the ladder into my wall, don’t know about the shock).
IIRC, we never really found out what happened as far as where the current came from. They don’t think it was the LX. The better witnesses swear there was an arc/blue flash of some description, and we were on a very old industrial site that had all sorts of weird wiring and strange building that wasn’t on any blueprints.
I feel sorry for the guy mentioned in the OP’s link - yikes. I’ve never heard of any longterm medical problems like that from an electrical shock. Either you’re burned a bit, zapped unconscious, or killed outright, but not that.
I’ve had some minor household shocks over the years, but nothing out of the ordinary. My parents and some friends of theirs got a bad shock 40-some years ago when the metal mast of a small boat they were launching very briefly touched a powerline that too hung low over the beach. One of them (I think one of the friends) was knocked off the deck into the water, but none of them had to get any medical treatment or had any longterm problems, IIRC.
A co-worker was hit with one leg of a 4,160 volt line. He lost a leg in that incident. One of the cutouts stayed in. This same man lost part of his left hand (i believe) when his fluke was set wrong and the blast also knocked out his partner who was standing behind him, as they both hit the wall.
Another coworker received 3rd degree burns to his hand when an arc flash with 480 (277) leg grounded while working in a panel.
I got knocked down when I was replacing my hot water heater years ago. I had the wrong disconnect pulled:smack:
as for the symptoms, I have many of the ones listed but Who knows where they originated:dubious:
An older electrician I worked for in the Navy told me about a time when he was working on a panel in a factory, tightening lugs with a very large and long screwdriver. He was also on a metal stepladder on steel plating floor, but the power was shut off so he thought he was safe. The main was shut off but not locked out, and his apprentice was supposedly standing guard to make sure nobody energized it.
He was never clear as to whether the apprentice left his station or closed the switch himself, but he came to in a hospital several days later with both hands bandaged heavily and various burns on his body where metal was present. Oddly enough, the ladder probably saved his life, possibly conducting the electricity better than his body did. The last thing he remembered was reaching out with the screwdriver for the panel bus bar.
Apparently, electricity arced from the panel to the screwdriver and crossed phases. The screwdriver melted, including the plastic handle, and the current somehow passed through his arm and down the ladder, welding it to the steel plating and throwing him across the room. The skin on his hand was pretty much burned off and a patch of his arm was badly burned, along with the soles of his feet, and he had the skin grafts to prove it. He was still having problems with his hands after many years had passed.
Believe it or not, I once saw a man being struck by lightning. The man just fell to the ground and was later taken to hospital. I never found out if he lived or died.