What is deadly for people

Electric current moves largely invisibly and unnoticed through our everyday lives. Its dangers are often underestimated and the handling of defective switches and cables is sometimes risky. Whether you can get away with a harmless tingling sensation from an electric shock or threaten cardiac arrest depends on several factors.

Normally, electrical devices and live parts are secured in such a way that the human body does not come into direct contact with the current or voltage. There is no danger to humans as long as they do not become part of the electrical circuit. This can always be the case if insulation is damaged or the electrical system is handled carelessly, e.g. B. with a defective socket, with bare cables or when reaching into a lamp socket. When touching live parts, the current flows from the hand through the body to the earth. It's an electric shock.

Tingling, cramping, flickering

Whether an electric shock is fatal depends on how long and with what strength the human organism is passed through. If the heart is in the current path, the chances of survival are slim. Life-threatening disorders of the heart rhythm set in at flow rates of around 80 milliamps. In so-called ventricular fibrillation, the periodic activity of the heart changes into a completely irregular one. The heart stops pumping blood. This leads to a lack of oxygen in the brain and this in turn leads to death within a few minutes. Only if it is possible to interrupt the flow of current before the end of a cardiac period (approx. 0.8 seconds) can large currents be withstood without dangerous damage. A slight electric shock is only noticeable by a tingling sensation in the fingertips. The shock that one gets, however, often leads to an accident. For example, if someone falls off a ladder or objects as a result of an electric shock. Even at relatively low currents, the muscles begin to cramp up to such an extent that the conductor cannot be let go of. Accident helpers can only remove the victim from the covered object by switching off the electricity or using non-conductive materials. The letting go threshold is 15 to 20 milliamps. From 30 milliamps, the respiratory muscles are also affected. There is a risk of breathlessness and finally respiratory failure.

Built-in security

Protective measures such as insulation prevent direct contact with live parts. Other protective measures take effect when power is misdirected, e.g. B. on the housing of devices. This includes overcurrent protection devices in connection with a protective conductor and residual current circuit breaker.

So that the electricity doesn't go wrong

  • All work and repairs on electrical devices (mixers, cutting machines, coffee machines) or system parts (cables, sockets, switches) should only be carried out by a qualified electrician. Never improvise.
  • Pay attention to damage to cables (insulation), sockets, switches and have them repaired immediately.
  • Have all electrical appliances checked regularly. Fixed devices every 4 years, mobile devices every 6 months.
  • In damp rooms, use switches and sockets with lids and lights with overcaps as damp room protection and use residual current circuit breakers (FI circuit breakers).
  • Reattach the cover cap after changing the lamp.
  • Never clean switches or sockets with water.
  • Do not touch electrical system components with wet hands.
  • Never reach into devices or parts of the system blindly.

The path of least resistance
Electric current always looks for the path of least resistance. Factors such as flooring, clothing or footwear and the moisture at the point of contact also influence the resistance of the human body. Bare feet on damp ground are extremely poor conditions for avoiding a fatal electric shock. Usually an averaged value is used for body resistance. One calculates with 1000 ohms with a current flow from hand to hand or from hand to foot. According to Ohm's law, the strength of an electric shock results from the contact voltage and the resistance. For a contact voltage of 230 volts (with which most electrical devices work) and a body resistance of 1,000 ohms, the result is a flow strength of 230 milliamperes. Even an electric shock of this magnitude can be fatal.