# What happens to your body if you touch an electric fence?

Below is the entire description of the material I’ve given to apprentices in the first year of their apprenticeship electricians. If you’d like more information on how you can achieve electrical security, please contact me and I’ll provide it. This is in relation to the 400V/230Vac 50Hz electrical power supply used throughout the world of civilisation.

1. The effects of electrical Shock

The body is a source of resistance to the flow of current. Over 99% all resistance of your body to electrical current flows is located at the skin. It is calculated in Ohms. Dry, calloused hands might contain greater than 100,000 O due to a thick outer layer dead cells within the stratum corneum. The body’s internal resistance is approximately 300 O and is a result of the salty, wet tissues underneath the skin. Skin resistance can be efficiently escaped if there’s the skin breaking down due to an electrical surge or a cut, severe abrasion, or an immersion in water. The skin functions as an electrical device, such as capacitors, by allowing an increase in current flow when there is a rapid change in voltage. A voltage that is changing rapidly is transferred to the palms and fingers of the hand when holding the metal object that suddenly contacts an electrical source. This kind of contact can cause a greater intensity of the current in the body than could otherwise occur.

The physical consequences of an electrical shock are dependent greatly on the length of the contact. If the power source can be quickly removed upon first detect of residual current there could be minimal or no negative impact. This is illustrated in Figure 1.

Figure 1: Log-Log-Graph of the Impact on Alternating Currents I T’s Duration Passing from Hand to Feet

In the figure 1, it can be observed that 30mA of body current must be eliminated within less than 400ms to stay within the (safe) AC-2 range. If a body’s electrical current exceeds 150mA, it is required to be eliminated within less than 40ms.

2. Line-to-line shock

A person in the figure 2 is hit with an electric shock of 400V when it touches the L2 and L3 that he’s in contact. The current travels between one hand and another across his chest via the lungs and heart. When he’s on a wooden floor that is dry and is not connected to the earth, and therefore there is no flow of current between his legs.

Figure 2: Shock Received Between Two Lines

3. Line – to Neutral Shock

The electrician shown in figure 3 is currently connecting the neutral conductor from outside circuits into the neutral busbar of the switchboard. The problem is that he’s doing this using a circuit that is already activated with the load already connected and turned on. The erroneous assumption that he’s safe because he’s in contact with neutrals could be shaken. When connecting a circuit be sure that the circuit is properly isolated (MCB switched off or the fuse is removed) Also, turn the load off.

In addition, the current flows through one hand and the next across his chest through the lungs and heart. Since he’s standing on a floor made of wood the floor is completely isolated from the earth, and therefore there is no flow of current between his legs.

Figure 3: Shock Received Between Line and Neutral

4. Line- to Line- – to Earth Shock

The figure 4 character holds an active conductor or metallic object that is livened due to the fault. He is on a concrete floor , which is electrically conductive. The shock current is flowing through his torso, arm and legs as it passes through vital organs along the route. Another variation could occur when the victim holding the live conductor in one hand, while holding an object grounded like the water pipe made of metal or faucet on the other. In this scenario, the path for the shock current could be from hand to hand and through the chest as shown in Figure 4.

It is most likely the most frequent type of shock experienced by the average person It is the kind of shock that the residual current device offers security.

Figure 4: Shock Received Between Line and Earth

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