This morning I got a 400+ volt AC shock by touching my bus and a metal pipe at a dump station at the same time. It woke me up enough to want to share it with other large-metal-RV owners (such as bus nuts). The whole story is posted over on my blog here:
http://ourodyssey.blogspot.com/2009/07/shocking-experience-at-dump-station.html (http://ourodyssey.blogspot.com/2009/07/shocking-experience-at-dump-station.html)
-Sean
http://OurOdyssey.BlogSpot.com
Sean,
That is an incredible story. I am going to have to reread it again, just to make sure that I understand it.
Thanks for the post.
God bless,
John
Induction, I wouldn't have thought that at all. LOL, I'd have been one of those, "I'll be damned! Whar did dat come from?" folks. ;)
Glad you didn't end up a statistic.
Sean,
Damn!
I have a friend who was operating a 44' dump trailer that got caught in the power lines. He did as we were all taught and jumped as far as possible with feet together. Unfortunately, this was one of the 200KV lines coming in to a mine site.
He now has no palms on his hands and the soles of his feet are scar tissue so far in that you can dig in with a knife and hit bone without his feeling it. I've seen him do it.
People on this board worry about propane in a coach, but I've seen just as deadly effects from our friend, "Reddy Electric"
Good thing you weren't wearing your tin foil hat ;D
I'm with Matt - I'd be standing there saying "duh - where'd that come from?" Although I have heard of farmers stealing power from overhead lines by carefully positioned fencing. I always thought that was a myth though.
Wow! I didn't know that those transmission lines created such a field! Did you warn someone? Thanks for that VERY helpful post!
Glenn
Sean,
Great story. That's good info to keep in mind. As Mattc said, I'm glad you didn't become a statistic. Besides, you put a lot of work into that turbo and it needs to be broken in. 8) Just kidding. Glad your okay.
Rick
EMF (Electro Magnetic Field) is in the work. Like a transformer...bus is a core to the high power line.
If you had a am radio on while under high power line....it will be buzz very loud instead of low level buzzing sound of most overheads.
Depend how high the voltage is and how far from the line...you can have lightning between coach's roof to line if you grounded the coach well.
That interesting to learn it was about 400v.
There should be a warning sign...no metal bus and truck van over 10 feet allowed.
Sojourn for Christ, Gerald
Are you sure it wasn't from eating that electric eel sushi ??? :D
EMF, the downside of a roof raise, guess well have to ad that to the list of considerations.
Wow, that coulda been bad, thanks for the reminder to look up and sharing your learning.
I have heard farmers in the old days would run long runs of wire along under the high tension lines and power there farm houses with the EMF. ::)
Me and electricity do not get along, if there is a way to get shocked i will find it even if people say '' you can't get shocked off of that". 4 or 5 years ago i worked on a couple of substation expansion jobs in the Yuma area. The first day on the job the boss told me he did not have a shirt, (orange) for me but would have one the next day and told me not to catch on fire. Being kind of a smartass :) i asked him if that was possible and he said yes. :o Turns out the shirts are treated to be fire resistant. Sometimes we were working directly under lines with different amounts of voltage at different heights and sometimes we were off to the side. I learned very quickly to jump on and off of the machines i was running instead of just stepping on and off while holding on to the grab bars. In some places just picking up a hammer or piece of rebar or even just nails off of the ground would give you a good little zap. Other places you had to wear rubber gloves and even then you could get shocked sometimes. It was fun to get a new guy on the job and tell him about this and see that he did not believe you........and then watch him the first time he grabbed something and got zapped. ;D
Using a high-impedance digital multimeter to measure the potential of a totally floating lump of metal near other live equipment is likely to result in very misleading readings. Load the metal mass down to ground with a 1 MegOhm resistor and then see what you read.
loading the metal mass with a 1 meg resistor would probably almost completely dissipate the charge. It would be really interesting to do that and read the current level. Back in the day we had to physically ground our vehicles before refueling, the first reason was static but the secondary reason may well have been this sort of thing. Having a ground strap for the dump station would have eliminated this, yes?
My house is almost directly under a 48KV line, two three phase feeds. Maybe I will do some experiments! free inductive power, maybe charge a battery or run some driveway lights! I wonder how big a coil i'd need to get a couple of watts out of it!
Brian
Sean, you were kind enough (???? :o :o) to have the turbo failure to make me feel better about my engine problems. I hope you don't expect me to reciprocate ;D ;D ;D
Jim
Ahhh, come on Jim, just go stick your finger in a socket and make him feel better. ;D
Very interesting Sean, thanks for the post.
Have you notified the folks that operate that dump station? Or the utility that operates/maintains the lines?
Sean, Even though there is a lot of voltage "open circuit" and it was enough current to make you pay attention, I wonder what the actual maximum current could have been? I bet it's not enough to hurt you. It would also have been interesting to measure the voltage under a load that mimics body resistance, to see what the voltage would have been. I bet under a load like that it would have only been a few volts at most. "Wet" can make you feel a good tickle even with 12 volts! That said though, your bus does present more than a few picofarads... (and I'm guessing it was a capacitive coupling scenario, not inductive...)
Curious curious....
Cheers
Gary
I'm sure Sean would have said something if there was actually something improper about the lines. What he describes is a normal effect, which anyone can easily reproduce. Florescent tubes under high voltage power lines at night is probably one you've heard about before. Here's a good picture: http://www.interactivearchitecture.org/richard-box.html (http://www.interactivearchitecture.org/richard-box.html)
I'm aware of the fluorescent light thing, and also aware that it's an effect but not necessarily dangerous. Many places in Alaska experience measurable voltage potentials of 1000 volts per meter during a good aurora display, but it won't necessarily kill you, because there's not a lot of current behind it, as might be the case in Sean's experience. There's a large grey area between getting shocked and being dangerous. I'm just curious where Sean's case sits... could be nasty, could just be an amazing (and excellent) story!
Cheers
Gary
Sorry for the delay -- my satellite has crapped out and I had to hunt for Internet access.
To Tony, Gary, and others: Yes, I am well aware that the open-circuit voltage as read by a high-impedance DMM is not the same voltage that I would read if the bus were connected to ground through a fixed resistance (including a body). And I suppose it might have been of academic interest to someone if I had fished out a one-megohm resistor, connected it between chassis and ground, then measured the voltage drop across it. Buy, hey, guys, it was 108° -- there's a limit to what I was going to stand around doing out there. Once I knew for sure I did not have a problem on board the bus, I boogied out of there (with apologies to Gary for stealing his nic).
All that being said, anyone just joining us here should know that I've been working with electricity for over three decades. Under 300 volts I work hot; above that, I try to have the power off, or at least be wearing proper rubber gloves that I have pressure-tested myself. So I've contacted 120, 240, and 277 VAC more than once, and I know what each feels like. A 12, 24, or 48 volt tingle would not have sent me scrambling for the meter, and of course, I knew instantly that it was 60-Hz AC. I would estimate just from the sensation on the skin that the jolt I got was from something north of 200 volts. The meter reading simply confirmed that.
As to whether this was "dangerous," that's hard to say. It is quite possible that, had I actually firmly grabbed both items, the charge might have drained down rapidly and only a small voltage might have been left over to actually drive current through my body, in the milliamp range. But I also know enough about EMF and electric fields to know that it very well might have been dangerous; more testing would be required to know for sure. Reference Dallas's sobering story, above, wherein I am guessing the gentleman, after properly leaping from the vehicle with feet together, then fell forward onto his hands, sending thousands of volts through both. Even three or four feet of separation on the (mostly dielectric) ground can hold that amount of potential difference when very high-tension lines are involved.
Several people have asked: Yes, I reported this "problem" to Westworld. They have referred it to management, although I do not really expect them to do anything about it. Perhaps they will erect a warning sign. It should be noted that the vast majority of RV's, which are mostly fiberglass and wood, would not experience this problem, or at least not to this extent. It would really only be metal-frame, metal-skin coaches such as our bus conversions. Which is one reason I wanted to report the event here -- so others can be aware of the hazard when parked near high-tension lines.
-Sean
http://OurOdyssey.BlogSpot.com
Yup, fell forward onto his hands, the fact that it's difficult to jump out of a semi tractor and get very far, I'm certain he was still within the dangerous area no matter how he landed.
Probably should have stayed inside till they shut the power off. Unless of course the rig was on fire. Have heard too many times where a person bailed off of a piece of equipment when it tipped over or went over a bank and got pinned or run over by it, but if they had stayed in it they would have lived.