I was wondering if anyone here knows of someone who was seriously injured or worse from coming in contact w/ a vehicle’s ignition-system high voltage? I have never heard of a serious injury from that myself, and wonder why not?
I have as well as most mechanics that have been doing this for many years have been shocked doing diags on OBD1 and older vehicles… And no I have never heard of a healthy person being hurt bad by secondary ignition system…
My MSD (multiple spark discharge, no ballast resistor, so full voltage to the ignition coil) 6AL with the 45-50K volts ignition coil will light your world up, but you tend to move away from it pretty quickly… And yes I have been hit by GM’s MDIS (multiple distributorless ignition system) as well as many others, coil pack(s), they will bite you pretty hard also…
It is not much different then being bit by your home 110V and or 220V’s, I have been bit by 110/120V’s many times as well as 220/240V’s messing with electrical work… Yes most of the time I flip the breaker(s) off 1st…
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Spark plugs fire with very high voltage and low current. The voltage gets your attention but it is current that will kill you.
I have never known, heard or read of anyone getting killed or even seriously injured by an ignition spark.
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Ignition systems do not supply a continuous current, allows the person to release their hand from the power source. Did you pull back and hit your elbow on the hood hinge of that early Ford?
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Yeah, the most likely injury is from banging into something during the rapid recoil from the source of the shock.
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LOL - or the sudden shock sends you reeling backwards and you smack your head on whatever you fall on.
I think if you’re dependent on electronic devices like pace-makers it can matter.
Heh heh. As a kid I managed to grab the spark plug wire on my Briggs. It went up my arm almost to my shoulder. Been gun shy ever since.
Wallpapering I would use a box cutter to cut around outlets and hit and exposed screw. I knew it but wasn’t that bad. Just my hand. A guy I worked with on habitat liked to wrap electrical tape around the outlet screws. Of course I never bothered. Like they say, screw around and find out.
Now I’ve heard of body men and mechanics not wanting to work on evs because of the high voltage.
My wife needed body repairs on her Odyssey. My Tesla was parked behind her car when the manager of the body shop came out to look at her van. He said that they would work on her car, took one look at my EV and said they wouldn’t touch it. My filter was on as I thought to myself “so what? I’m not here for repairs and I drive carefully to avoid accidents”. Yes, I take fewer chances than before I got the Tesla.
That is because IF you get hit by the HV system of a Hybrid (I don’t imagine an EV would be any better) you will never know it, it can/will cook you… I don’t know if the newer stuff has any safe guards built in other then the main disconnect for the battery, then the older ones did…
I would not let any shop not Hybrid/EV certified come close to one that I (if ever) owned it…
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The big difference there is AC versus DC. A DC shock causes the muscle to contract rapidly once and that causes you to let go or get jolted away from it. AC on the other hand is bipolar and 60Hz is faster than the reaction time of your muscles so you have a hard time letting go or being jolted away from it. Sizzlelean! 
Skin resistance varies widely in the population and then there are other factors that determine how much current will flow. For the most part, all you’ll feel is a sharp pain for a brief period from ignition systems. The biggest risk as noted is a secondary injury. However, people with pacemakers need to be very vigilant when working around high voltages…or other sources of electromagnetic fields…
Like microwave ovens. I don’t have a pacemaker. When a stupid doctor wanted to put one in me I looked into the issues, and people with pacemakers are warned to step back several paces when they start a microwave oven. I never got the pacemaker because the halfwit doctor confused severe anemia with heart beat irregularities. Dumb because he had the data but was too busy to look at it. I fired him.
I have very fast reflexes in general, that being said, I had always heard that 110V can/will make you grab it, but 220V will tend to knock you away from it… I normally move my hand/arm (whatever) away from either voltage very quickly, just as I do when hit by secondary ignition, I have never grabbed it… lol
BTW, my dryer receptacle bits me almost every time I have to mess with the dryer (for whatever reason I move it), my daughter laughed her backside off last time she was helping me cause I told her to be careful around it and then bam, my big hand got to close and it got me again, you have to plug the dryer in and then finish moving the dryer back, the receptacle is in a bad location obviously… 
+1 …Good comments all around. cigroller’s post gets the “solution” tag. EV’s are another matter altogether, but are not the OP’s topic, so I didn’t review those comments. It sounds like serious conventional HV ignitions system injuries are rare, but could conceivably occur, especially to an electric-shock sensitive person. Good info to consider if recommending that a diy’er check for spark.
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Standard recommendation - if you know what you’re doing, work on electrical systems with one hand behind your back, if you don’t, with both hands behind your back…
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Yeah that’s what I do but usually have the circuit off anyway. Sometimes it’s hard to know if you have the right one though.
Now I have come to dislike metal conduit. I just don’t like the idea of the pipe being the ground wire. The neighbor had his garage done in conduit and as a kid got bit. So have never trusted the stuff.
Then I discovered I have two switches in a double wall box downstairs. Each one on a different circuit. I put a warning note for the dumb electrician (me), until I can get around to putting in two single boxes and the wall repair. Don’t fir the life of me know how I did that but the downstairs wiring is a little complex.
Interesting discussion. A very short electrical pulse (like for a spark plug) contains a wide spectrum of frequencies. Seems hard to believe, but electricity doesn’t move along a wire from source to destination the same way at low frequencies compared to high frequencies. At high frequencies it sort of clings to the surface of the wire rather than moving down the center core. This could be a reason why auto manufacturers use braided ground wire for the ground connection to the spark plugs and coils. Braided wire has a lot of surface area, so it effectively lowers the wire’s resistance at higher frequencies.
You put a solution in place and then ask more questions, now everyone has to deal with that stupid pop up saying this topic has been solved every time they want to reply… lol
Automotive wiring is flexible and much less prone to breakage under movement from vibrations and parts movement such as the engine/trans moving around, abs sensors, pad wear sensors etc…
Solid core wire is thicker, and offers higher current capacity, and when bent will hold it’s shape better.
I like that!
I put this sign on a piece of equipment once- the Ops mgr took offense…
Achtung to Lookenspeepers
Das machine und ekqipment ist nicht fer gefingerpoken und mittengrabben.
Ist easy snappen der springenwerk, blowenfusen und poppencorken mit spitzensparken.
Das machine ist nicht fer gewerken by das dumkopfen.
Das rubbernecken, sightseeren, keepen hands in das pockets, relaxin and watch das blinkenlights.
We were told of an engineer that was a pretty careful guy. One day he leaned in and his metal scale in his shirt pocket contacted a mains terminal. That tells you how long ago that was He survived but was rushed to emergency care with physical effects of a significant shock to the chest.
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My high school shop teacher claimed he knew a mechanic who got is wedding ring across the starter terminal and pulled his ring finger off as the wedding ring got welded in place. That of course is not the question here. I have been shocked by the HV wire of the coil and/or spark plug wires and the shock hurts, but no long term damage.
As for electricians, AC will cause your muscles to contract, i.e. grip. DC will just burn you, you may not even feel the voltage, but you will feel the burn.
Not only was I taught to keep my left hand behind me, I was also taught to approach a wire with the backside of my hand. If it was live, it would make you pull away.
NOTE: This is not how you test for a live circuit. You first insure that the breaker is off or the fuse is pulled and then check with a voltmeter. But after insuring all this, still make that first approach with the backside of your hand.
My brother the electrician (residential US, so AC voltage) would never wear anything metal for work - esp his wedding ring.