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01:10
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Q: Way to calculate the dangerousness level of volts+amps? (don't want to learn the hard way)

Samuel WalkerIs there a formula to calculate the dangerousness of amps, and volts? like watts, for example. Watts = Volts x Amps. Generally speaking, you could say wattage takes into account volts, and amps. I am working on a robot. And am using high power motors. I don't want to learn the hard way, by gettin...

why do you think that the wattage is the thing to watch out for?
I don't know. If there is an actual formula to calculate the shock level of volts + amps, then that would be great. I just though watts would work because it takes into account both volts and amps. @jsotola
There are a number of ways electricity can harm you- wattage might be important if you're worried about burns. It can weld a wrench to a wedding ring and cost you a finger.
Shock level depends on many more factors beyond voltage or current. E.g. if you pierce your skin with electrodes and run 12 volts that can easily be fatal if it goes across your chest. If your skin is intact and dry, you won't even feel those 12 volts.
Are you wet or dry? Is the current path from one finger to another on the same hand or on different hands? Skin resistance and current path are important elements. In short, there's too little information to safely answer your question as stated...
Ok. how about 12v of electricity at 80A? @BobT
@SamuelWalker, again it depends. Are you hands wet? Are you touching the wires with one hand, or both? Also the 80A is a red herring, as it refers to the current capability of the supply, and not what will flow through your body. If it were 8000A or 8A it would be just as dangerous, as 0.02A are enough to stop a healthy heart.
As for where my hands are placed when touching it. My hands are never wet, (can be sweaty at times), and as for the placement of my hands, I probably would be touching the wire with one, however, not a guarantee.... @anrieff
So now I am a little confused. How would 0.02A be able to kill you? is that in context of how many volts are being used? Or is there more to the equation? I mean, I have touched a 2600mA 5v power pack before, and I haven't felt anything... @anrieff
@SamuelWalker, you are confused because you think that if a power source is capable of delivering 80A, then it must deliver 80A. It doesn't. Most power supplies (incl. batteries) are voltage sources. They don't force a specific current through the circuit, the circuit resistance determines it. With dry hands, you can be approximated as a 20kohm resistor for example. At 5V, with you being "the circuit", the current is 0.25mA - you won't even feel that. At 12V it's 0.6mA, still not enough to be sensed even. With wet (or sweaty) hands your resistance is much lower, so current is higher.
If 20mA flows through your heart muscle it can cause an arythmia
01:10
"12v 80A" "high power motors?" A lot of people would call 480 V, 240 A a medium power motor and 4000 V, 80 A a high power motor. Shock danger is somewhat proportional to voltage. Heat danger in normal operation is somewhat proportional to normal current. During motor overload or stall it is proportional to overload or stall current. During a short circuit, is proportional to short circuit current and energy released before a fuse blows.
Here is the stator of a really large motor: emerald.com/insight/proxy/img?link=/resource/id/…
Ok. I think i am understanding now. So, bottom line, if i was holding a 12v 80A power source with both hands, and my wire was 1ft long at about 18 AWG and my hands were moist, how dangerous would that be? Shock wise and burn wise? @CharlesCowie
Shock wise, you might jump a bit if you touch the bare terminals. Heat wise, you might get a nasty burn.
So, as i am understanding, i would essentially have to become part of the circuit, with the circuit load pulling 80A for me to get that kind of shock, right? @CharlesCowie
No, you would become another circuit (assuming you touch both terminals). At 12 volts, you would pull practically no current.
NEC code puts a voltage limit of exposed conductors at 48 VDC or 36 VAC sinewave. Current is more of a hot-wire issue, not a shock issue.
Volts times amps is watts, so if not a shock hazard it could be a burn hazard.
A 25 watt solder iron will burn you as it is confined resistive heat. In this case the volts and amps that drive it are not so important.
I know someone who grabbed phase A and C of a 600 VAC 3-phase surge suppressor. The image of the copper bus bars are forever burned into the palms of each hand. How he survived we do not know.
Because our body acts like a resistor, doubling the voltage puts 4 times the wattage through our body. 480 VAC hits 16 times as hard as 120 VAC.

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