How do the Acti9 MCBs behave with high inrush currents?

How can we help you today?

How does a high inrush current affect the Acti9 MCBs?

High inrush currents can affect Acti9 MCBs (Miniature Circuit Breakers) in a few ways:

Nuisance Tripping: If the inrush current exceeds the instantaneous trip threshold of the MCB, it may cause the circuit breaker to trip, leading to unwanted interruptions in service. This is particularly common with loads like motors or transformers that experience high inrush currents at startup.
Selection of Type: Choosing the right type of Acti9 MCB is crucial. For example, Type B MCBs trip at lower inrush currents and are typically used for residential applications. Type C MCBs can handle moderate inrush currents and are suitable for commercial applications, while Type D MCBs can manage high inrush currents, making them ideal for heavy machinery.
Time Delay Features: Many Acti9 MCBs are designed with time delay characteristics that allow them to tolerate high inrush currents for a brief period without tripping. This feature helps avoid nuisance tripping during startup phases.
Thermal and Magnetic Protection: The MCBs utilize both thermal and magnetic trip mechanisms. The thermal trip operates on prolonged overcurrent, while the magnetic trip responds to short-circuit conditions. Proper coordination between these mechanisms is essential to ensure that high inrush currents do not lead to premature tripping.

While Acti9 MCBs are designed to handle high inrush currents effectively, selecting the appropriate type for your specific application is critical to prevent nuisance tripping and ensure reliable operation. Please check the trip curves for the Acti9 MCB's in section 11 (see below).