Which is more dangerous A/c voltage or DC?

[ddawg16]

This is my point. The "current" of the circuit does not matter one tiny bit. It is the current flowing through you that matters.
You can get 5mA flowing from many sources, from a 5mA source to 2000A or greater.

Continuing with what speedy is talking about.....

The body has a certain 'resistance'....typically in the order of 100K ohms or higher. For there to be any current flow, the voltage has to be high enough. Standard ohms law stuff. So....120vac is going to put a little over 1ma of current through the body....it doesn't matter if it's AC or DC....it will be a little over 1ma...or, a little over 0.12w.

Lets look at one example where someone is subjected to over 100Kv.....static electricity......you don't see people dieing from that....

It's really rare to get killed directly from 120vac....what happens more often is that it causes someone to fall...and the fall is what injures or kills the person.

Now....if a person is sweating...wet...etc....their 'resistanc' is lower....so, more current can flow through the body....more wattage.....more cooking...of body parts.....

If you were to examine the bodies in the above pics (I have copies of them as well), you would find they are basically cooked.....and I mean, really cooked.

 

[Engineer61]

The resistance across a human body is more like 30 KOhms. In my freshman college physics class the professor had about 30 of us hold hands to form a long chain, then put 10 KV across the chain. We just felt a mild buzz in our palms. Body resistance can vary quite a bit depending on how much you are sweating, dry skin makes a poor electrical connection with the outside world, sweaty skin makes a very good electrical connection.

 

[CaseyJoes.]

This quote always gets me.
It's NOT the amps of a circuit, appliance or thing that kills anyone. It is amperage flowing through the body that does harm. You can get just as killed from a 120V 15A lamp cord as you can from one leg of a 240V 1200A switch gear.
It's all in how the voltage is delivered to the body. A taser will only ALLOW a certain amount of current to flow. Just like a GFI receptacle. You will still get a shock, but it will not allow the amperage to reach lethal levels.

At the same time, you can grab a 12V 1000CCA car battery by the terminals and not feel a thing. It's the voltage that is so low it is not allowing the amperage to flow through your body since the body's resistance is so low to such a low voltage.

So saying "it's not the voltage that kill, it's the amperage" is not entirely true.

This... said it before I could

 

[KiarraNowlin]

Well Everyone know that DC is more dangerous rather than AC.

 

[Jarcese]

I've worked on high voltage hands on since I left high school. I understand how, why, and what it looks like when you get shocked at different voltages. I've seen people die or become disfigured and I've seen people laugh a shock off. I've never been shocked myself and I'm not looking to be shocked. We all know both currents are dangerous and deadly.

I keep prodding because I'm just curious to see any experiments that have been done. I've never seen an experiment with real numbers excpept for the link I posted. "My EE teacher told me DC makes you hang on" is not an acceptable answer. Pretty much all the answers so far are not facts. I get asked questions all day and I usually tell people that AC is more dangerous because it's more likely to affect your heart, but that's only because what people have told me, not showed me on paper. I've seen plenty of articles on what it takes for AC to hurt you, but not DC. I would imagine either type of current across your heart at low amperage can affect heart rhythm, so why do we always say AC is worse for that reason?

BODILY EFFECT DIRECT CURRENT (DC) 60 Hz AC 10 kHz AC
---------------------------------------------------------------
Slight sensation Men = 1.0 mA 0.4 mA 7 mA
felt at hand(s) Women = 0.6 mA 0.3 mA 5 mA
---------------------------------------------------------------
Threshold of Men = 5.2 mA 1.1 mA 12 mA
perception Women = 3.5 mA 0.7 mA 8 mA
---------------------------------------------------------------
Painful, but Men = 62 mA 9 mA 55 mA
voluntary muscle Women = 41 mA 6 mA 37 mA
control maintained
---------------------------------------------------------------
Painful, unable Men = 76 mA 16 mA 75 mA
to let go of wires Women = 51 mA 10.5 mA 50 mA
---------------------------------------------------------------
Severe pain, Men = 90 mA 23 mA 94 mA
difficulty Women = 60 mA 15 mA 63 mA
breathing
---------------------------------------------------------------
Possible heart Men = 500 mA 100 mA
fibrillation Women = 500 mA 100 mA
after 3 seconds
---------------------------------------------------------------

 

[wyliesdiesels]

Interesting!

 

[Erampu]

It's kinda like asking "Would you rather be in a Smart or an SUV when the train hits?"

 

[Jarcese]

What kind of train? I agree but I've never seen an actual answer on the subject even if it is apples to apples.

 

[nehog]

Well Everyone know that DC is more dangerous rather than AC.

No, everyone doesn't know this. In fact, only people who are not experts in the field seem to know this. I will admit it is a complex subject, where voltage and other factors come into play, but that generic statement is shockingly wrong.

 

[Stuart in MN]

There's really no way to answer this question...it depends on the voltage and amperage, the physical conditions, how you contact the electrical source, and probably a dozen other factors.

 

[Roots]

....but I've never seen an actual answer on the subject even if it is apples to apples.

It's only with a slight bit of trepidation that I post again in this thread. There's countless definitive studies and experiments out there, expressing the minute distinctions in the danger of AC versus DC at different voltages, amperages, and AC frequency. I even mentioned that in my first post.

I'd really implore those who are electrical professionals to seek out such studies, for the professionalism of our field. For everyone else there's no reason too as they're both such effective killers that any slight differences are effectively miniscule.

 

[wyliesdiesels]

There's really no way to answer this question...it depends on the voltage and amperage, the physical conditions, how you contact the electrical source, and probably a dozen other factors.

That's a good point! There's too many variables!

 

[ddawg16]

Well Everyone know that DC is more dangerous rather than AC.

Don't you just love those enlightning posts from new members.

 

[wyliesdiesels]

 

[gayler]

Wow! 54 posts. I.m glad to get everyone thinking and in on the debate. I guess the real answer is they are both dangerous. For the record the voltage and amperage I was thinking of in DC is between 300 and 400 Volts and mabe 1 Amp, useing capacitors of maybe 22Uf or so.

 

[BigGMC]

I'm more concerned about how all these wireless signals are affecting my brain and I work around high voltage nearly everyday..... I think the gov't knows what I'm thinking. Are foil lined hard hats really effective?

 

[wyliesdiesels]

 

[jawnd393]

I got a shock from 250 dc once. There was a lot of 250dc power in the steel mill. It been a lot of years but I still remember how it felt. DC can grab and contract your mussels in a way that that feels very different from ac. I just brushed against and it was a fleeting thing, but it left a memory. They are both dangerous. I respect ac but I'm scared of 250dc.
JohnD

 

[nehog]

... useing capacitors of maybe 22Uf or so.

A capacitor is a different game. You are less likely to suffer cardiac arrest (possible, but unusual) but you can suffer many other injuries such as spot burns, reflexive injuries (arm jerks and hits other things) and pulled muscles, etc.

A frequent problem with capacitors is that you get bit, jerk away, and end up hitting a live wire, sharp edge, falling off a ladder, and that is what really ruins your day...

BTW, whey you discharge capacitors either use a resistor/jumper wires setup, or an old junk screwdriver as many capacitors will leave a divot in your screwdriver! A 100K resistor across the capacitor for a minute or so will discharge it down to a safe voltage in most cases (can vary with capacitance and voltage however.)

 

[gayler]

A capacitor is a different game. You are less likely to suffer cardiac arrest (possible, but unusual) but you can suffer many other injuries such as spot burns, reflexive injuries (arm jerks and hits other things) and pulled muscles, etc.

A frequent problem with capacitors is that you get bit, jerk away, and end up hitting a live wire, sharp edge, falling off a ladder, and that is what really ruins your day...

BTW, whey you discharge capacitors either use a resistor/jumper wires setup, or an old junk screwdriver as many capacitors will leave a divot in your screwdriver! A 100K resistor across the capacitor for a minute or so will discharge it down to a safe voltage in most cases (can vary with capacitance and voltage however.)

I agree with using a discharge tool. I usualy just leave it cliped on the whole time as they can build up a bit of charge again.