Why Can’t a 12V Car Battery Electrocute You?
As we know that current is responsible to kill, not the voltage. But voltage (like a pressure) is needed to flow the current in a conductor. It means, amperes kills, not the volts. Now the question arises here why a 12V battery (household or vehicles) are harmless even with high amperage? Let’s see why doesn’t the car 12V car battery electrocute or hurt you or if there is a chance of electrocution by a 12V car battery.
Keep in mind that the stored voltage in the battery is DC. There is a little bit difference between AC and DC while the effect of electric shock is severe on the human body, no matter which one is more dangerous AC or DC?
To the post, you may have experienced the direct contact of both terminals of the battery with bare hands without feeling an electric shock. Right? Following is the reason behind this magic.
Actually, it is the current which is responsible for saver shock but electric current won’t flow if there is not plenty of pressure (voltage). The next thing is resistance and yes, almost every material has some of them. Similarly, the human body has some resistance (100,000 Ohms in dry condition and 1000 ohms in wet condition).
Now suppose a human body torches both terminals of battery (positive and negative) with bare hands.
According to Ohm’s law:
Dry Condition where human body resistance = 1 × 105 Ω)
I = V ÷ R
I = 12V ÷ 100,000Ω
I = 0.12 mA
Throughout Wet Condition where human body resistance = 1k Ω)
I = V ÷ R
I = 12V ÷ 1000Ω
I = 12 mA
While analyzing the above calculations, the 0.12 mA (in touching 12V battery in dry condition) is not even sensible while the barely perceptible amount of current is up to 1mA. This is because the voltage is too low to push the current in the body having a high resistance up to 100kΩ. This is the same case of aluminum smelters (where each smelting pot is powered by very high amperage and only a few volts) or welding machine.
Similarly, a low amperes with high voltage even wont kill you. A tabletop Van de Graaff generator generates very high voltage up to 100,000 volts but little amount of electric current and children still playing and enjoying the hair-raising experience without being harmed. This shows, both voltage and current (which is the mixture of electric power) is responsible for severe shock and fatal injuries.
In the second case (touching battery throughout wet conditions, like rain, snow, sweating, humidity) the resistance of the human body reduces up to 1k ohms means there is a chance to flow more current in the human body. In this case, 12mA current is flowing through the human body which is not a good sign. A 3-9 mA current will feel a painful sensation while 9-25 mA current won’t let you go with muscular contraction. And yes, the 12 mA current falls in this category.
There may be a chance of no electric shock even with (a little bit) wet hands (because a high amount of resistance still exists between both hands or the battery has almost discharged or never fully charged). Keep in mind that the above calculations are for a fully wet body (like standing in the rain). So never ever touch the battery terminals with bare hands while rain, snow or wet or sweaty hands.
Conclusion:
A 12V battery won’t electrocute you because the applied voltage from the battery source is not enough to push the required amount of current in the human body having a high amount of resistance. That’s why a 12V DC battery won’t hurt you at all. In other words, it is the electrical energy which leads to serious damage, burn, electrical hazard and even electrocution. In short, the mixture of current and voltage (electric power) is responsible for electrocution.
Precaution:
- Never ever short the battery terminals with conducting materials (it makes a short circuit), otherwise, it will pure at once all the stored power it can which leads to serious injuries and hazardous fire.
- Never ever swap/switch and connect the opposite terminals of battery to the load i.e. negative to positive and positive to negative. If so, there will be a huge surge of power and a higher amount of heat will be produced.
- The leakage (of acid) of the battery can burn your skin.
- A spark or flame very close to the battery may explode due to the hydrogen gas from the battery.
- Shorting the both terminals of the battery may explode the battery and lead to a hazardous fire.
FAQ
Why don’t we get shock from the battery?
Your skin is not a very good conductor of electricity, and a standard car battery at 12V doesn’t have enough voltage to punch through that insulation layer to the much more conductive inner tissues. Generally under 50V is considered unlikely to give you a serious or dangerous shock
Can you get electric shock from 12V?
In most ordinary circumstances, 12 V isn’t even enough to feel, let alone cause a shock. However, it’s really current that you feel and that shocks you, not voltage
What happens if I touch both terminals of a 12V battery?
12v 100Ah battery is quite normal to see everywhere which I have touched, nothing happens if you touch both terminals. Reason is that voltage level of 12 is very low to create any damaging burns
Is 12V AC safe to touch?
Up to 48V is considered a ‘safe’ voltage, but you can definitely feel it and DC is far more dangerous than AC (because with DC your muscles contract and stay contracted so it can be very difficult to disengage from the source)
Can a 1.5 V battery shock you?
You can safely put your fingers accross a 1.5 V battery because the skin resistance prevents any significant current from flowing. As shown above, it would take 1.5 kΩ just to get 1 mA. Normal skin resistance is in the 10s of kΩ at least
How many volts is lethal?
It is sometimes suggested that human lethality is most common with alternating current at 100–250 volts; however, death has occurred below this range, with supplies as low as 42 volts
Can you get shocked while jumping a car battery?
Here’s the good news: It’s probably impossible to electrocute yourself from jump starting a car. The battery might give you a big shock, but the voltage is too low to penetrate your skin and put you down for the count
Is 12V always DC?
Is a 12V Battery AC or DC? Like all batteries, a 12V battery uses direct current (DC). This applies to any device that runs off batteries. From your camera to your laptop or your car battery to a 12V battery
