Can 400 Volts Kill You? - BoatAnchors Forum at eHam.net

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Can 400 Volts Kill You?	Reply
by K1YTG on August 20, 2008	Mail this to a friend!
I have had several 400 Volt shocks when working on Ham gear in the last week. I have been working on such gear for the last 40 years. But have just had worse than usual luck lately. I have not had shocks like these since the 60's. The good news is that I'm still here with no damage that I can find. Does this level of voltage comprise a lethal threat? I'm I lucky, or will 400 Volts not usually do you in? I have other rigs with 3000 Volts on the plates. I have had no run ins with the 3000 Volts. Norm

RE: Can 400 Volts Kill You?	Reply
by KA5N on August 20, 2008	Mail this to a friend!
You've got to be kidding! 115 VAC can kill, 400 VDC (and less) can kill. It is just a matter of the current and the current path. Have you never heard of the old adage: "keep one hand in your pocket"? Which means avoid getting current across your heart if you get shocked. The dangers of electrical shock cannot be overstated. Read up on it, do a google. Allen

RE: Can 400 Volts Kill You?	Reply
by WB6BYU on August 20, 2008	Mail this to a friend!
400V from one hand to the other, passing through the heart, certainly could be fatal. The same voltage applied from the tip of a wandering finger to the forearm resting on the front panel is more likely to cause sudden arm movement and discoloration of the air due to the sudden release of verbal invectives. Keeping one hand in your pocket won't prevent the latter, but it reduces the opportunity for the former. There is a difference in how the body reacts to a shock from AC or DC: with DC the reaction is generally a sudden muscle contraction that is likely to break contact with the applied voltage. With AC the muscles may be paralyzed so that contact is maintained for a longer time. But it isn't a good idea to take chances with either.

RE: Can 400 Volts Kill You?	Reply
by W3LK on August 20, 2008	Mail this to a friend!
I hope your wife has a big, fat life insurance policy on you - and a funeral policy, as well. :) 73, Lon - W3LK Naugatuck, Connecticut

RE: Can 400 Volts Kill You?	Reply
by WB2WIK on August 20, 2008	Mail this to a friend!
Depends a lot on the surface moisture of your skin, which varies resistance all over the place. As Dale said, a shock from hand-to-hand, which conducts through your chest, is surely more lethal than one from hand-to-elbow on the same arm! One that kills people is hand-to-foot because the unfortunate person was not insulated from the floor, which was at ground potential (like a cement floor in a basement). That routes the current through or near the heart, also. Not good. Finger-to-finger shocks on the same hand are very rarely lethal, because it's not a critical path. Just as a data point, I've had 2000-3000V shocks hand-to-foot many times and I'm still here! But those were when I was young and reckless. I try very hard to avoid that, today. One of the most damaging incidents I've ever seen was caused by 12V DC. No kidding. It was when a backyard mechanic wearing jewelry was working on his car and his gold bracelet shorted + and - terminals of a car battery. This is not enough to electrocute anybody, but the bracelet was such a good conductor it short-circuited the battery extremely well and burned a "ring" on his wrist that's still there, 30 years later -- a permanent scar. Not pretty, and caused by twelve volts (at probably 300A or so). WB2WIK/6

RE: Can 400 Volts Kill You?	Reply
by KE4DRN on August 20, 2008	Mail this to a friend!
hi, http://www.allaboutcircuits.com/vol_1/chpt_3/10.html 73 james

RE: Can 400 Volts Kill You?	Reply
by KA8NSG on August 21, 2008	Mail this to a friend!
Sheesh! As a medic also. Only 300 ma across the heart path will kill you!!! The old rule is keep one hand in your pocket! Any voltage will kill you, Its the amprage behind it! Worked as a electrican for a few years too and even I have been zapped by 110 VAC. and had a pair of linemans pliers take a full 240VAC. They look like a welder was taken to it! I got a glancing tickle from that and took the rest of the day off. The flash did bother my eyes from that! Dont give the potential a easy way to ground! Best is have all equipment unplug/shut off before you open the case!!!

RE: Can 400 Volts Kill You?	Reply
by K1YTG on August 21, 2008	Mail this to a friend!
How can I get voltage readings on the tube plates, screens, grid , and cathode? The unit needs to be opened up and operating to take the readings. How else am I to know if it is running as designed? If the caps are leaking HV to the grids. If the plate resistors are correct and the tubes drawing the correct amount of current? What safety precautions are there for getting into the guts of a tube chassis while it is powered up and under load? Norm

RE: Can 400 Volts Kill You?	Reply
by SWL377 on August 22, 2008	Mail this to a friend!
Yes, 400 volts can kill you. If you are going to keep working on live HVDC gear, get an implantable heart defibrillator installed. It might bring you back if you go into V fib. I am just joking, but these have saved several people who would have otherwise died from electrical shocks. They just happened to also have heart arrythmias that justified the implant that saved their lives when they got zapped. I skydive and I consider working on boatanchor gear with live voltages more dangerous. Really! If I have a malfunction with my main chute, and I have twice in 40 years of jumping, I can release it and deploy my reserve canopy. If I am working on my ART 13 xmtr live, get careless around that 813 and take 1000 VDC right through the heart? GAME OVER.

RE: Can 400 Volts Kill You?	Reply
by KE4DRN on August 22, 2008	Mail this to a friend!
Hi Norm, you have good questions, I remember someone posting the steps they take when they work on HV equipment. Once you have discharged they rig and it is safe, you check it one more time. Remove all jewelery and wear safety glasses. Place one hand in your pocket and use the other to work the equipment. Then you hookup your meter probes and then power the rig on and read the meter, then power it off and discharge. Repeat the cycle until you get all your readings, two or more meters with the appropriate test leads rated for HV are good to have. Never, ever work on this type of equipment alone, always have somebody in the room to get help if you get into trouble. 73 james

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