NEC Commercial Electrical Practice Test

What does the term 'non-linear' indicate in reference to electrical loads?

1. Inconsistent power supply

2. Variable energy consumption

3. Current waveform distortion

4. Static electric discharge

The correct answer is: Current waveform distortion

The term 'non-linear' in reference to electrical loads indicates current waveform distortion. Non-linear loads draw current in a manner that varies with time, often causing the current waveform to deviate from the ideal sinusoidal shape. This is typically due to the load not being directly proportional to the voltage applied, leading to harmonic generation. Common examples of non-linear loads include power supplies, LED drivers, and electronic equipment that use rectification and switching techniques. This distortion can cause various issues in an electrical system, such as overheating in conductors, equipment malfunction, and interference with other electrical devices. Understanding that non-linear loads can significantly affect power quality is essential for proper system design, including considerations for harmonics and the sizing of conductors and transformers to mitigate potential issues. The other choices relate to different concepts. Inconsistent power supply refers to fluctuations in voltage or current but does not necessarily indicate distortion; variable energy consumption describes a load that changes its demand over time without specifying the waveform nature; static electric discharge involves the sudden release of stored static energy, not directly tied to the load's linearity in terms of current flow.