What is the regulation range of a step regulator?

The regulation range of a step regulator is indeed set at 10% below to 10% above the nominal voltage. This means that the regulator is designed to maintain the voltage level within this specific range to ensure proper operation of electrical equipment and to maintain a consistent power supply.

This regulation is important for preventing damage to electrical appliances caused by voltage fluctuations and for ensuring that the service provided to customers is reliable and within acceptable limits. Keeping the voltage regulated in this manner helps stabilize the electrical grid and improves the efficiency and performance of the entire power distribution system.

In contrast, the other options specify wider regulation ranges which are not typically achievable or practical within the context of standard step regulators. Regulators need to operate efficiently within tighter tolerances to effectively support the functionalities they are designed for.