Getting shocked with engine running - Page 3 - SailNet Community
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post #21 of 105 Old 11-19-2011
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Quote:
Originally Posted by mitiempo View Post
That is not 12 volts.
If I understand Ohms law, to get the high voltage to arc, the amps or watts would have to be cut back drastically. If the amps were cut back that high voltage would be akin to static electricity - a Van Der Graaf generator has about 40K volts, so it must be the wattage that suffers. No?

That would indicate that Boatpoker is correct - the amperage is the problem.

Of course I get a man in most times when I need electrical work done.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
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post #22 of 105 Old 11-19-2011
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That's right. An ignition coil produces 20,000 or more volts but at low amperage. The voltage has to be high for the spark to jump across the gap of the spark plug. It is less dangerous than 110 volts from an outlet in your house. But it can be felt. Anyone who worked on cars (when they were easy to work on) has probably had a buzz from a coil. I don't know if it can kill, never held onto one long enough to find out.

Does the original poster have a gas engine?

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post #23 of 105 Old 11-19-2011
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I found this interesting article concerning the voltage/current needed to injure or kill. As it states, it is the current that kills but voltage is needed normally to overcome the resistance of the skin. There are factors that can change this - contacting a ring on your finger for example. Generally 30 volts is the threshold of danger which pretty much leaves 12 volts in the safe range.
Ohm's Law (again!) : ELECTRICAL SAFETY
Well worth reading.

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post #24 of 105 Old 11-19-2011 Thread Starter
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Thanks for all the ideas. I'll report more after investigating this afternoon. FYI, diesel, no inverter......
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post #25 of 105 Old 11-19-2011
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300-500 mA of DC current can cause fibrillation which leads to cardiac arrest.

It's the amperage that's providing the shock...i.e how much current is flowing, not necessarily the source of the current.

I've seen guys get severely shocked working on guitar tube amps that had zero current running to them at the time. However, the amperage was already built up inside.
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post #26 of 105 Old 11-19-2011
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I was away from the dock but didn't have time to trace. I'll go out tomorrow and see what I can find
do you have an inverter on board making 110volts?
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post #27 of 105 Old 11-19-2011
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Quote:
Originally Posted by emoney:798520
300-500 mA of DC current can cause fibrillation which leads to cardiac arrest.

It's the amperage that's providing the shock...i.e how much current is flowing, not necessarily the source of the current.
We've been over this. Yes, amperage is the danger. But skin has high resistance that the current has to get past to cause damage. High resistance makes for low current.

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post #28 of 105 Old 11-19-2011
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We've been over this. Yes, amperage is the danger. But skin has high resistance that the current has to get past to cause damage. High resistance makes for low current.
Wet hands .... wet feet .... lower resistance.... Water ? surely not around a boat !

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post #29 of 105 Old 11-19-2011
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We've been over this. Yes, amperage is the danger. But skin has high resistance that the current has to get past to cause damage. High resistance makes for low current.
Tell that to guy getting shocked....
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post #30 of 105 Old 11-19-2011
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Tell that to guy getting shocked....
Right, many, many years ago I was a telephone installer/ repairman. Ringing current was 20 cycle 80 volts AC, not sure how much amperage, but probably not much. That being said, when standing on wet concrete and getting zapped with it my involuntary reflex resulted in throwing my lug wrench about 30 feet away. "Talking" current was 48 volt DC with minimal amperage, when I wet my fingers I could feel a slight tingle from one finger to the next, a lazy way to see if the pair was "hot". I hate getting shocks, especially from leaky
ignition wires while working in close quarters while an engine is running. I guess everybody has their own tolerances, mine just happens to be very low.

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