Out of all the topics that I can post about, grounding is by far one of the most important. The NEC (National Electrical Code) article 250 gives us the guidelines for grounding and bonding electrical equipment and systems. I will not go into any technical details about grounding. however I will give a layman’s description of what the grounding conductor does and why it is so important.
Electrical current normally takes a path through the phase conductor also known as the “hot wire”, through the load returning to the source via the grounded conductor also known as the “neutral conductor”. This path that the current normally takes constitutes what we call an electrical circuit.
When the current takes a path outside of the electrical circuit we have what is known as a fault condition. If this situation was to occur, the current could take a path that was accessible by people and contact could result in electrical shock or death. So as we can see it is very undesirable to have a situation where the current takes a path other then the intended electrical circuit.
So what then is the job of the grounding conductor, the simple answer is that the grounding conductor routes the fault current to earth hence the word ground. Because the earth has a lower resistance than our body the current will take the lower path of resistance to earth. Because the ground path has little to no resistance the current has nothing to hold it back causing it to rise to extreme levels in fractions of a second this is what is known as a short circuit!
When we have this short-circuit situation the sudden rise in current causes tremendous amounts of heat, this in turn causes the circuit’s protective device to open thus clearing the circuit (tripped circuit breaker). So as you can see the role of the grounding conductor is one of great importance and failure to install it properly in your electrical circuit could result in severe bodily injury and perhaps death.
It is through safe and well designed electrical grounding systems that we eliminate some of the potential dangers that could arise as a result of our interactions with electrical equipment in normal every day situations. I will be writing more articles in the future that will take a more technical approach to the different techniques that are used to design safe and efficient grounding systems.
