Final answer:
In 1879, Thomas Edison's invention of the practical incandescent light bulb marked the beginning of the electrical industry, revolutionizing industrial operation and daily life by providing a safe and bright source of light.
Step-by-step explanation:
The event that took place in 1879 that caused the electrical industry to be born was the invention of the practical incandescent light bulb by Thomas Edison. This invention fundamentally changed the way people lived and worked, allowing for factories to run over longer hours and homes to be lit safely and brightly after dusk. The success of Edison's invention paved the way for the development of electricity as a primary source of energy, transforming industries and daily life, and sparking the Electrical Age.