It may seem like a long time ago, but with respect to the age of the earth, electricity is in its infancy. When such famous names as Franklin, Edison, Tesla, and Volta were mesmerized by that “blue flame”, who could have imagined the unlimited potential (no pun intended). Electricity is part of everyone’s life and living without it is practically impossible.
The biggest task after the discovery of electricity was developing a way to generate and harness such a wild beast. Today, we walk into a room, turn on a light, appliance, fan, or any number of devices but never really think about exactly how the power got to its destination. Since usable electricity does not exist naturally, it must be generated. Almost all commercial electricity is produced using a turbine driven by wind, water, or steam to rotate a magnet inside a coil of wire commonly referred to as a generator. A group of generators or power plant can then be used to send electricity via transmission lines at very high voltages to power substations where transformers reduce the voltages down to voltage that is suitable for consumer use and distribution.
Once the power is in a usable state, it is connected to a series of fuses and circuit breakers (ANSI Device 52) commonly referred to as switchgear. Switchgear is used to control, protect and isolate electrical equipment in addition to de-energize the equipment for maintenance or to clear faults downstream from a breaker.
During the turning “ON” of circuit breakers either for new installations or after equipment maintenance or repair, there exists the possibility of significant fault currents due to wiring errors or conductors being in too close proximity of each other or ground. This is a condition known as “arc flash and blast”. Arc flash is the immediate light produced with the fault. Arc blast is the release of energy from the fault that can be strong enough to throw personnel to the ground and cause equipment damage. Arc blasts can also result in hearing loss and can cause loose equipment, tools and debris to become deadly projectiles.
SHELLCO advertisement in the issue: “Breaker Control Time Delay Relay for Arc Flash Protection”