Zahara asked in Science & MathematicsEngineering · 8 months ago

# how high would the voltage from a live wire have to be in order for it to electrocute someone?

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• 8 months ago

Enough voltage to pass .075 amps across the present resistance of your body.

Not the voltage that kills, it is the current.

Defibrillators range to 3 Kv and peak over 50 amps for pulse of under 5 Ms.

This can restart a heart, likewise can also stop it.

For me, 120vac gives a good jolt,,240 has knocked me off a ladder.

35Kv at 120Ma Dc knocked my lights out, potentially lethal. a lucky day.

12 million volts at a couple Ma just a bit of a bite. (van de graaff generator)

• Markus Imhof
Lv 7
8 months agoReport

...and the fall off the ladder was more of a problem than the 240 V :-)

• roger
Lv 7
7 months ago

UL says that any voltage over 42 bolts can be dangerous.

• Steven
Lv 7
7 months ago

It depends on many variables. Those include what part of the body the current flows through, is it wet, what is the power frequency, how strong and fit is the heart of the victim, how long is the exposure, and more.The odds of being electrocuted by 120Volts is about 10%, 240V is about 50%, 480V is about 80%. The odds of being electrocuted by less than 50V is about 1% so it is considered safe.

Static electricity and Van Der Graaf generators are very high voltage but these sources have very little current/charge so they rarely cause any damage to humans.

• Anonymous
8 months ago

The so called limit is 50 volts. But, there have been those killed on 42.

I get zapped on the 200KV output of my Tesla coil and only feel a tingle. It is the current and the frequency that kill, not the voltage, alone. It also depends a lot on Where. 110 volts thru the hand; shock, burn, probably not death. A few mA thru the heart, no matter what voltage, can kill, especially if person has pacemaker, they can be dudded by the RF alone from a Tesla Coil. No electric shock at all.

• 8 months ago

I think 50 volts

• 8 months ago

In real life, it is totally dependent on the conditions.

eg. If otherwise insulated, you can touch (or work on) a live cable with no harm.

This guy is working on live cables operating at 500,000V...

https://www.cablejoints.co.uk/images/gallery/uploa...

If accidentally bridge bridge across & neutral or ground terminals with one hand only, it will hurt (a lot) and possibly cause burns but as there is no current through your body, not lethal.

At the other extreme, in wet conditions so you skin resistance is low, either standing on a conductive surface or touching a grounded item with one hand and touching even 110V (or possibly far lower) with the other could be fatal.

As others say, it's _where_ the current passes through your body that is the critical part.

Contained within one limb, a relatively large shock is unlikely to be lethal, Across your chest and only tiny currents are needed to possibly cause death.

• 8 months ago

More than 50V if human has bare foot standing on wet earth.

• 8 months ago

Not very high. It really isn't the Voltage as it is the current. It doesn't take much more than 5 milliAmperes running through your heart to kill you. That is why ground fault circuit interrupters (GFCI) are set to trip at 5mA. However, you can use Ohm's Law to perhaps figure out what a body's resistance is and how many Volts are needed to allow 5 mA to flow. Problem with that is the resistance of the human body changes, giving a wide variety of answers based upon ambient conditions.

• 8 months ago

Greater than 30 V is considered lethal in some situations. This is why cars operate on 12v and trucks use 24V. Aircraft use 24-28 VDC.