Safety and Protection

Are you excited about Electricity ? You may have to know much about the enormous behavior of  current. No, it wont bite you unless you are not cared about it.

     Here we bring some safety and protection aspects in electrical power handling. As we know the current is the flow of charges, which exists if and only if  there is potential difference and a closed loop(otherwise ideally we could say infinite resistance in the path, resulting in zero current).
   When we are focusing on our safety its better to consider the after effects as there is a potential and closed path, when we make some contacts.It's all that matters is the threat of electrical shock. It depends on the power level of the source, that it could circulate a certain amount of charge per second through your body.
The different current levels and effects are as follows

 1mA - some threshold of sensation
10mA - effect may vary from Mild sensation to painful shock
20mA - sticky behavior, so cannot let go of it
30mA to 40mA -Severe shock and results in muscular paralysis
50mA to 70mA - Extreme breathing difficulties, Hearts tends to stop
100mA - Death could be the result
>100mA - Severe burns and Breathing stops

                                            NB: information may vary from person to person and depends on source

   Specifically the body resistance handles the current ranges from shocking as it varies from point to point in the body, ie, in between ears it is around 100ohm (so that a lesser voltage level could harm and damage brain). But in the case of hand to feet its around 500ohm. As the resistance value increases the voltage levels have to be more (or the power sources have to be capable to circulate a meaningful current).
    Certainly the importance of the power source have to be considered for safety and protection.

From the following typical sources we could clear this idea

1. Van de Graff Generator 
To energize sub-atomic particles in nucleus, research purposes Vande graff generator is important for the production of high voltage DC. But it is capable of only supplying small currents in micro ranges. So that such voltage level could be touched by ourselves as there won't be much shocking effects

2. Arc welding machine
 In Arc  welding we need much current to produce large amount of heat to utilize it for melting and joining metals.So as to achieve this we use a step down transformer making low output voltage and high current.

   Well, other than theoretical data we have to be more practical with these.

Safety measures in usual practice is much more. Some of important rules for safety when dealing electricity can be listed as,

 1. Avoid dealing with energized systems
You may don't know how the system designer setup it and about the malfunctions , so there won't be any second before something bad occurs.To ensure this pull out it's connection from plug
2. Consider all these as energized ones, as there may be some charged capacitors in the circuit.
3. Always use insulated instruments for any troubleshooting of equipments. Unless it's like you are directly choosing the trouble.In addition with this ensure that you are not wet or on a wet floor.
4. Avoid all metal wearings if there is something like rings,bangles,metal watchbands etc.
5. Try not to use equipments in cold conditions. There might be any chance of condensation.Also remove water content on body if exists
6. Prefer the single handed operation for working with electricity as it will avoid the chance of current flow through rib cage including lungs and  heart in an undesirable situation.
7. If someone got contact with live conductor, immediately turn off the power supply. In these situation use an insulated material to rescue the person in danger and to touch something live.
8. In case of any necessity to touch the equipment, use back side of plam. It minimizes the risk of shocking effect. 

9. Most importantly, Expect the Unexpected