What is the maximum permissible voltage drop for final circuits?

The maximum permissible voltage drop for final circuits being set at 3% for lighting circuits and 5% for other circuits adheres to common standards in the electrical industry that ensure efficiency and safety. A voltage drop that exceeds these limits can lead to inadequate performance of lighting fixtures and potentially cause appliances on other circuits to operate improperly, which could affect their longevity and efficiency.

For lighting, a 3% voltage drop is often recommended to maintain adequate brightness and performance without significant dimming. In contrast, the 5% allowance for other circuits accounts for a broader range of devices that might tolerate a higher drop while still functioning correctly. These percentages strike a balance between safety and practicality, ensuring that electrical systems remain efficient while minimizing energy losses. Understanding the rationale behind these limits contributes to effective circuit design and installation practices.