can I get zapped touching my dc bare wiring?

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can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 14 2017 3:20am

I damaged my 36 volt battery wire and it's become exposed. I thought since it was dc that even if there were current flowing it wouldn't shock me. Even if I were wet. I think I might be dangerously wrong. It's hooked up to the esc on the table and I touched the wire and I think I felt a shock! clue me in please. I'm getting clued in the wrong way.

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Re: can I get zapped touching my dc bare wiring?

Post by dustNbone » Jan 14 2017 3:41am

36(ish) volts might give a little tingle on dry skin, it's unlikely to do any harm though. If your skin is wet, you'll feel it for sure, but it's still not going to kill you. Generally anything under 100 volts is "safe" for contact with dry skin. That doesn't mean you feel nothing, it just means you don't have to worry about dying.

AC or DC it's going to give you a zap, the difference with DC is that because the current doesn't reverse polarity 50 or 60 times a second like AC, the tendency is for muscles to contract and stay contracted until the current is removed, where as AC tends to "throw you off" it. That can be very dangerous if you find your hand wrapped around a high voltage DC bus bar or wire, as you physically may not be able to pull yourself away from it. Again, we're talking about voltages substantially higher than your 36V pack delivers.

The real danger from these batteries is the hot plasma that erupts when a short occurs across the power leads, this can cause severe skin burns and damage your eyes if you're looking at it. This can occur at fairly low voltages, it's more a product of the amperage that a big battery can deliver, which in the case of most ebike batteries is considerable.
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Re: can I get zapped touching my dc bare wiring?

Post by kdog » Jan 14 2017 3:44am

human skin ranges in resistance from like 100,000ohm to several 100s of ohms (if pierced over a short distance). age ,humidity, wetness, saltiness(sweat), thickness all play a factor. generally anything under 60V is considered safe for an adult with dry skin. if you have wet thin skin and a 42v battery you well could feel a tingle but is not usually dangerous even from hand to hand because it wont exceed the 'let go threshold'.
for young children with wet hands this could be very unpleasant but I still don't think it would be dangerous.
I definitely got a noticeable tingle with wet hands @ 75ish volts across them and a very unpleasant shock at the same V when a sharp edge of nickel punctured my skin. but still nothing I couldn't voluntarily recoil from.
LSS- it should be fine unless you do something really dumb like stick it on your tongue or give your self a transdermal thoracic zap

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 14 2017 12:20pm

with ac you can become the ground so the current would want to flow through you but in a battery scenario I'd have thought the current would ONLY want to travel to the other pole. If i were not BETWEEN the two poles I though Id be ok, such as simply touching the live wires and being in a way BESIDE AND TOUCHING, but I got a shock! So the current is maybe using me as an additional conductor getting from one pole to the other and its not an issue of the different in voltage between myself and the battery right? that's really my question.

I

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 16 2017 9:49pm

thanks for your thoughts so far. I think this is maybe a misunderstanding and I bumped my funny bone! I get hyper sensitive to every sensation or noise when around the battery. Or.. I can touch my bare aluminum battery wire with my wet hands and it will be no problem as long as I dont also touch the other pole at the same time. of course. but if I touch the single bare wire while current is flowing through it to the opposite pole my hand would be used as an extra conductor and then Id get a zing?! I think I felt something.

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Re: can I get zapped touching my dc bare wiring?

Post by dogman dan » Jan 17 2017 7:13am

You can get zapped by 9 v. Ever touched one of those dry cells to your tongue? That of course, completes the circuit to the negative pole of the battery.

But touching a hot 36v wire with bare hands, and something on your feet,, you should not have felt much tickle. Touching bare wires is a bad habit,, you should try to break it. Working one handed is a very good idea with any hot wire, any voltage, and touch it only with insulated tools. Don't be holding on to that aluminum ladder with one bare hand either.

As said above,, the real risk is touching + and - wires together. Like cut a plug off a battery cutting both wires at once, or working with the battery wires with both poles uncovered at once. Kentucky Fried Fingers is the term we like to use, or just KFF.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 17 2017 11:03am

So if it's a live dc wire that I'm not between the poles so to speak with a hand on either pole but instead just touching on the sidelines so to speak with a single finger on the bare aluminum...I'll become an additional conductor and things could get worse if I were to integrate additional conductors such as from touching aluminum or a wet floor? So this is different than being grounded with Ac and instead of the current going through me into the ladder and then ground as with Ac I'd be adding a conductive pathway that starts at my finger and circled around my body and the ladder and back to the same finger touching the wire?

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Re: can I get zapped touching my dc bare wiring?

Post by burner1 » Jan 17 2017 11:18am

Connecting the batteries on my 72v buggy I wasn't watching the terminals my arms were dragging on. It zapped me pretty good a couple times.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 17 2017 11:38am

Woow a couple times! But u were the sole circuit between the two terminals right? what if the terminals were connected and u just happened to be touching "on the sidelines"? I think if I used the multimeter it'd show zing potential on the sidelines. Putting a finger in the circuit even if a compete circuit would be adding an additional conductor/pathway for current
Which brings up its said u need to be between the poles to get killed as the current needs to pass ur heart, but if any additional conductive material is added to the circuit it will be used in its entirety, and not just the shortest path, and therefore u should be able to get killed from just a single finger touching as your complete body would become a conductor. No?

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Re: can I get zapped touching my dc bare wiring?

Post by Recumbent Bicycle Source » Jan 17 2017 4:53pm

Am I missing something here? Why not just cover it over with a small piece of electric tape?
Recumbent Bikes - My Recumbent Bike site for people who want to know more about them.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 17 2017 5:00pm

Yea easy to fix just curious how getting zinged can happen. Being the sole conductor between both poles is an obvious zinger but being an additional conductor to a competed dc circuit also will happen. my question is how come it's often stated you need to have the current pass your heart and therefore if you use one hand you're safe, but if you're whole body will become a conductor and the current won't just take the shortest path you could in theory have one finger touch an exposed wire and get killed. No?
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Re: can I get zapped touching my dc bare wiring?

Post by markz » Jan 20 2017 5:21pm

I think 72V is a good high value but I personally would not go 96V or higher. But I am not a speed freak either, I prefer offroading and hill climbing. I went 60kph(40mph) on my MXUS on the road keeping up with the SUV in front of me with no other cars behind me and it was fun, but I was very aware and paid high attention to my surroundings and the road ahead of me as I did not want to hit a pot hole or something else. That for me speedwise is my sweet spot, but I rarely go that fast, its a rare occurrence. My high end is 40kph(25mph) and my "all the time" end is 20-25kph.

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Re: can I get zapped touching my dc bare wiring?

Post by spinningmagnets » Jan 20 2017 5:29pm

The international standard for DC penetrating DRY skin is around 60V or above. The more volts, the worse it is. If you've been sweating and your skin is salty and wet, any volts will short across your skin (even if it doesn't penetrate. I say that because...high amps will burn you in a very painful way. There are pics on the internet of a 12V truck battery making a wrench glow red. I've heard wrenches called "100 amp slow-blow fuses".

DC is much worse than AC, because of the alternating nature of AC. Since the AC current passes across a zero-volts point 60 times a second, its easier to pull away (not "easy" but easi-ER). Once DC gets flowing, its a constant current. Also, if you touch something with the insides of your fingers (in the normal way) electricity can sometimes make your hands clamp down (muscle contraction) and you can't let go until the circuit is broken by a fuse or breaker.

When I was a kid, we had an electric hot-dog cooker, and the only protection was that it had a clear plastic shield, and you had to close it to press the "on" button. the dogs inside were impaled near their tips, and they got a direct 120V AC feed from the wall. They cooked in just a few seconds. That is what electricity will do to your hands, it will cook the flesh the whole time you are trying to pull away....

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 20 2017 6:33pm

when I was looking into making a stun gun with minimal parts I read ac is more effective as the resistance of the skin is lower. impedance decreasing with frequency.
The getting stuck situation... maybe it's ac.
https://www.quora.com/Which-is-more-dan ... r-DC-power

great video at the bottom
https://www.youtube.com/watch?v=hp97GjuULX8



but what of my question! Have you ever touched a bare dc wire while it's charging or discharging? I imagine it would use you as an additional conductor, as much of your body as depending on the resistance with dc or frequency and impedance of your skin and how far it can get through you I'd think. use your whole body to get even if touching just within a 1mm space with one finger you would become an additional conductor, assuming it gets through the skin. So you could die from one finger touching a wire WITH CURRENT GOING THROUGH but not when there is no current flowing. YOU BECOME ADDITIONAL CONDUCTOR. ac more so. so at max speed on your bike you touch your bare wire and get zapped but not when you're stopped at a light as theres barely any current flowing through. I'd think it was safe to touch the bare wire even if it was many volts as long as it was hooked to the esc and drawing little current. too afraid to try it though, probably for the best. It would be getting into a circuit that's already limited to what the esc is putting out at the time.

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Re: can I get zapped touching my dc bare wiring?

Post by kdog » Jan 21 2017 6:02am

A while ago I was riding home in the rain a bit nervy...and I thought I got a zap on my knee as it brushed the battery box. It was a sharp little sting but I couldn't figure it out. Kept riding and got it again... Turns out a seam in the case was grabbing hairs as my knee went past ripping them out! Phew! Not 84v about to destroy my manhood.

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Re: can I get zapped touching my dc bare wiring?

Post by markz » Jan 21 2017 2:34pm

SpinningMagnets worded it excellently and the words of the day is USE CAUTION, and BE AWARE, Know What You Are Doing, Be Informed and most importantly Be Careful.

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Re: can I get zapped touching my dc bare wiring in line w es

Post by Hummina Shadeeba » Jan 21 2017 3:07pm

I'm trying to be aware by figuring out if you become an additional conductor when using dc and brush against the bare main wiring. If that's the case, and the esc is putting out lots of current to the motor, from the battery, THEN i could get zapped touching this bare wire if it breaks through the skin, as I'd be an additional conductor, and I WOULDN'T get zapped touching that same bare wire if the esc was not allowing current to flow through the wire.

assuming a 100v system Id get no strong zap while waiting at the light and touch the bare wire, but then a huge zap if I touch that same bare wire when accelerating at full. ?

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Re: can I get zapped touching my dc bare wiring?

Post by Alan B » Jan 21 2017 10:49pm

The motor sees full battery voltage when it is powered. The current to the motor is controlled by the duty cycle.

To get a shock current must flow through you.

Six volts can be fatal if the resistance is low, such as skin penetration.

Insulate everything, you should not ground the system to the frame and you should not touch any conductors.

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Re: can I get zapped touching my dc bare wiring?

Post by kdog » Jan 22 2017 12:27am

The amount of current flowing through a wire doesn't change the zap factor of that wire for a given V. If you are talking about wire from controller to motor then the throttle will vary the voltage in the phases, and therefore the zap factor. Battery to controller wires- no difference.
For a given voltage the only thing that will matter is the resistance you present to the return path.
If there is no current path though you, then you can touch any single live wire at any V ( don't try it) and theoretically not get zapped. The idea will fail at mega V's but you know what I mean. But seeing as we only need a few mV to feel the effect, at higher voltages you need very high resistance to be safe.
At your battery voltage- you needn't worry unless you crash and impail yourself through the chest on your battery terminals- I reckon your safe.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 22 2017 3:49am

hold on i think i'm going crazy. bear with me. let me see if i can word this better. Lets say we have a 200 volt battery, I can touch the negative bare wire on my battery no matter what voltage it is, similarly i can rub myself all over the positive end and nothing will happen, if I got between them...no lets you you got between them, thats bad and you'd be fried badly, now i hook an esc up to the battery and its off, we get you all rubbed up on the positive and all over the negative wires separately but always separately, you can't get all three of you together, and then I turn on the esc and there's maybe half an amp current just to keep the lights going or something and you feel it and you don't like it because at 200 volts with one amp is ..um..maybe 200 watts, and it's then with the throttle in my hand that I can put whatever current that I want into my motor through you as you're now an additional conductor with your hand stuck to my bare wire. I can just let a trickle through and leave it like that, but if I also all of a sudden on a whim decide i feel like going full throttle I could and then the resistance of your skin would already be like jello and it would travel solely in and out of your body through the tiny spot on your finger where you were touching, and the resistance of your skin would resist but with enough voltage you would be drenched from head to toe in heart stopping current. Or maybe you would just explode.

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Re: can I get zapped touching my dc bare wiring?

Post by Alan B » Jan 22 2017 9:56am

It only takes about ten milliamps to affect your heart. It takes two connections to make a circuit and flow current, but often one of the connections is not obvious, such as through the shoes to ground and on to a grounded supply like wall power. Since a bike electrical system is not grounded it takes two direct connections. Touching with both hands is very dangerous since the current path is very nearly through the heart.

Learning basic electronics (and electrical safety) is best pursued by taking classes, reading books on the subjects and finding sources on the internet that specialize in these subjects. Use an internet search engine to find information rather than asking questions that have been discussed by experts across the internet already. ES is not the best source of general electrical information that is already well covered elsewhere.

Your DC wiring should not be bare. Inadvertent shorts will damage or destroy your equipment as well as present electrical risks to anyone touching them. Insulate them. Tools like heatshrink, electrical tape, or liquid electrical tape can be used.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 22 2017 2:55pm

you guys are all talking past my question and telling me to be safe. I have a very specific question related to dc that is in a completed circuit that a person could become an additional conductor within. what if you aren't the sole connection BETWEEN the battery poles but BESIDE AND TOUCHING and the current is controlled by the esc. This is a theoretical question about how current flows when an additional, bad, conductor is added:

can you suck on your bare battery wire if it's connected to the esc and the esc is off?? I'm guessing yes as you're in possibly a circuit but no current is flowing
can you suck on it when under full throttle?? I'm guessing only if you want to be seen as an additional conductor...and that current would try to use as much of your body as the impedance or resistance would allow, and that you could be killed in this way if the voltage were high enough and you were not having an obvious direct current going past your heart as the current will try to take as many paths and as much area as possible and it depends on the voltage and hz

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Re: can I get zapped touching my dc bare wiring?

Post by Alan B » Jan 22 2017 7:32pm

This is basic electronics. Current divides based on the impedance ratio of the paths available. Current will flow in all complete paths that have a voltage differential.

If there is a voltage across a path, current in that path will be determined by ohm's law. I = E / R.

If there is PWM involved, such as on the output of an ESC then the current will be pulsed and the average current will be lower. Inductive kickback from switching can cause the voltage to be higher than the battery voltage. This is how sparks are generated when the points on an engine open and the collapsing magnetic field makes 15+kV from 12VDC.

If the circuit is off and there is no voltage, there will be no current.

Batteries are never off, so upstream of the ESC the voltage is always present unless a switch or connector opens the circuit.

The ESC is six FET switches which are switched both for commutation and for PWM control of motor current.

If your battery/ESC system is not grounded you have to touch it in two places to get a shock (current flow through your body).

If current passes through your body it can burn and damage skin and/or internal organs and cause muscular contractions, heart fibrillation and death, depending on the magnitude of current.

All wiring should be insulated for equipment protection and personnel safety.

If you suck on wiring you may get serious burns in your mouth. The cabling generally contains both poles.

Your questions have been answered several times already in this thread.

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Re: can I get zapped touching my dc bare wiring?

Post by Hummina Shadeeba » Jan 22 2017 9:18pm

"Current divides based on the impedance ratio of the paths available. Current will flow in all complete paths that have a voltage differential."
if that's the case you can get a current through your heart by only touching only one battery wire when the the throttle is pushed as long as the voltage and frequency is enough to get through the skin far enough to get to the heart. I sense your frustration but this question hasn't been answered yet and only now are you confirming what I suspected. not meaning to have a fit but honestly it hadn't been answered yet. and still hasn't yet in that I haven't had it confirmed that no you don't need to have an obvious current path through your heart as from touching both poles with separate hands to get killed and you could get killed with just touching with one finger if the voltage and frequency to break through your skin to get to the heart were great enough. Even if you were just touching a passing current with one finger.

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Re: can I get zapped touching my dc bare wiring?

Post by Alan B » Jan 23 2017 2:15am

At DC you have to have a path, two points connected to differing potentials. A single point doesn't define a path, or a voltage differential. There's nowhere for the current to go. Your volt meter and ammeter has two probes. You won't get a DC voltage or current reading with only one probe connected.

Here, better to study it from a real source rather than consume ES bandwidth:

http://www.allaboutcircuits.com/textboo ... t-current/

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