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It's the Volts that jolts and the Mills that kills. (Mills is milliamps).
Static electricity can give you a shock. Although the voltage is very high, these shocks are not usually dangerous. However a current of a few milliamps can be fatal.
The risk of an electric shock from low voltage circuits (5 or 12 Volts) is very low.
The risk of electric shocks from mains circuits (230 Volts) is quite high if you don't take care.
If you accidentally touch a live circuit, the current depends on the electrical resistance of your body. If you have dry hands, the current will be small and although painful, the shock is unlikely to be very dangerous. With wet hands, an identical shock could be fatal. This makes kitchens and bathrooms much more dangerous because of the water.
Effects on the Body
- Muscular Spasms or Contractions: This is most dangerous if it causes you to grip the live circuit. You might be unable to let go.
- Burns: Electric currents have a heating effect that can cause burns. This becomes much more dangerous with high voltages and radio or microwave transmitters.
- Psychological: The surprise and pain of a shock can cause you to behave in an unpredictable way. For example it might make you fall off a ladder.
- Your Heart: Large currents can cause you heart to stop working.
What to Do
If you need to help someone who is getting an electric shock, this is what you should do.
- If possible, turn off or unplug the power. Do not touch the victim until the power is off.
- Call loudly for help and if necessary phone the emergency services.
- If the power can not be turned off, use an insulating object to disconnect the victim from the power. Dry clothes, a broom handle or any insulating object can be used for pulling or levering.
- Put the victim in recovery position.
- Check for breathing and heart beat and apply cardiopulmonary resuscitation, if necessary.
With quick action and correct first aid, most people survive very serious shocks.
- Dry skin has a high resistance so little current flows. Dry skin electric shocks are rarely fatal.
- Wet skin has a much lower resistance so lots of current flows. This can be highly dangerous. Kitchens and bathrooms are much more dangerous that other rooms without water.
Circuits that are turned off can still be fatally dangerous.
- Large capacitors can store a lethal charge for days after the circuit has been turned off.
- Shut down power lines can still carry a very large static electric charge which is highly dangerous.
In both these cases, the circuits must be discharged to ground before any maintenance work begins. Video
- The large currents heat the victims outer layers and clothing.
- Removing superheated clothes quickly can greatly reduce the burns suffered by a lightning strike victim.
- Nasty Pictures
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