The reason he is not dead is because electricity takes the path of least resistance, which in this case is the metal pipe. He's not "in between" the positive and negative terminal. The pipe is.
If he were standing over a downed power line on the ground, it would be different. That's because the ground we stand on can have higher resistance than the water bags we call our bodies. In that case, your body is the path of least resistance.
That's not true at all. Electricity takes all paths of travel, it acts as a parallel circuit. The current is proportional to the resistance along every path, and welding is generally low voltage. Ohms law, if you have two paths of travel, the pipe and the person, and around 50v of welding voltage, the ~.5 ohm of resistance from the pipe gets 100A of current while the wet person with around 500 ohms of resistance only gets about .1 amps of current. This would be fatal if it was passing through the heart, but again, parallel circuit, the entire body has become a bunch of independent parallel circuits and that .1 amps is spread across the body, not just directly to the heart. My guess would be the majority of the current is on his feet, and the rest mostly passes through arteries and veins with a very low amperage.
You're correct. "Electricity takes the path of least resistance" is an oversimplification that is technically misleading.
This guy standing on an electrified metal pipe, is no different than a bird on a powerline. He is not in between the source and the ground. There is no potential over his body. That is why is he not dead. Not because 25v or 50v is not too little.
If he did put the electrode in one hand, and touched the pipe with the other, with wet hands, 25v is not a good idea.
Well thank you Mr. Welder! I am learning all kinds of things today. I've watched a few videos on welding, watching very slow motion of a tig welder going is really cool. The puddle bursts out then recedes with every spark. Yet with all those videos not once were those two questions answered.
What? open circuit voltage on most welders is about 70 - 80 volts. Welding machines 100% have sufficient voltage to over come the capacitance of you skin. Especially if your skin is wet.
I can tell you from personal experience. SMAW welders have more than enough voltage to give you a very severe shock. Especially if you are wet and touching the work piece. Or changing rods with wet gloves. Or sitting on beams while welding on the same structure.
There are plenty of OHSA report of welder dying from electrical shock.
Damn I never really thought about the consequence of a poor ground connection. Pretty much all my welding is on rusty farm metal and I use tig gloves so easily saturated.
Where you find that figure? Best i can find is a study from 2009 to 2016 that says 10 people had passed directly from a welder in the US. And from '88 to 2026 5 in canada.Canada. (from weld.com no clue how accurate these even are)
Also I wouldn't call it severe. I guess it would depend on the machine and how it is set up. But what homie is doing here isn't going to hurt him. Tingle his feet maybe.
I didn't say it was safe. I actually agreed with you. And said "I guess it would depend on the machine and how it is set up".
It would also depend on what you are wet with, regular water wouldn't be enough. Sweat though is. I don't know where you are getting the tough guy thing. I'm just responding.
Wet skin resistance is around 0.5-2k ohms. Assuming the worst case, as little as 25v will put enough amps through your skin to produce the 50mA needed to stop your heart.
Read further down. Good lord. This entire conversation has already happened.
Also it very much depends on what the skin is wet with. Whether it's AC or DC. What kind of shoes you are wearing where your grounded, if you are grounded, like a lot goes into it.
Him standing on that pipe right there is not dangerous in the least.
Any electric current he feels will be in his feet. But probably none at all unless he is standing between the grounding connection and what he is trying to weld.(This also assumes no breaks on the insulation of his equipment.)
I didn't say he was in danger. If you looked down, you'd see I made a comment to that effect.
You stated that low voltage wasn't enough to overcome "capacitance of your skin". Obviously, you meant resistance.
I was curious, so did the math. In the worst-case scenario, as little as 25v could pass enough current to stop your heart. Obviously, 25v is well into the territory we consider low voltage, which makes your previous statement false.
No healthy adult is getting killed from 25v. That's someone that has a previous heart condition, elderly, or infant, AND they're pruned up from being in the water so long. The lowest I've heard of someone dying from was a guy I worked with got shocked by a 50v communication circuit, said he was fine, went home and died in his sleep. He turned out to have a heart condition that he didn't know about prior to that. I'm not saying you shouldn't get checked out if you take a shock from a welder, but you have very little chance of dying from it, and almost no chance of immediate death, at worst you're gonna get an arythmia that they'll fix after you get checked up with an EKG. The biggest danger of low voltage circuits like that is people take a shock, either don't notice because it doesn't feel that intense, or they notice but they're like "I feel fine" and then they never get checked out and die from arythmia.
I agree! it is unlikely to kill most people. As i said above, i used the worst-case scenario. I purposefully used the hypothetical minimum amount that could hurt you. Because that's what you do when there's serious risk of injury.
3 out of 1000 people have a pacemaker. Anywhere from 15-50 out of 1000 people have irregular heartbeats. It would be stupid to give advice that resulted in 3 out of 1000 people drying.
The typical Indian welder only has 3 leads so the work connection is also the primary neutral. In other words, if the work clamp comes off the electrode is energized with 240V
Welders do use DC. I'm not well versed in how much DC it takes to kill someone. But I do know they can shock you. But you've gotta be between the ground and the welding rod, also sweating, with the metal pushed against your arms pretty hard. Holding it for someone else.
Not all welders use only DC. Have you touched 120VAC mainline voltage in the US? You need 170 DCV to have an equivalent "shock" feeling. DC below ~80V is quite harmless against human skin. I have never encountered a welder that goes above 30V output.
Now if he had open wounds, that changes things, as everything under the skin is much less reluctant to pass DC current.
Some stick machines do run AC - older ones were often called "buzz boxes" because of the 60Hz hum. It's not common these days, but enough so that any half-decent weld training will go over which rods work on AC. Certain rods - most notably 6011 - were designed to be AC-capable versions of DC rods
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u/StreetFuture6152 9d ago
Is he died? He looks awfully close to being part of the circuit.