Frequently Asked Question
In-rush current and power capacity
Last Updated 6 years ago
What is in-rush current:https://en.wikipedia.org/wiki/Inrush_current
https://electricalschool.org/inrushcurrent/
In-rush currents are related to motor-based loads, so please consider to oversize your UPS if your load is going to consists of considerable size motors. Details about in-rush (starting) current should be checked with the manufacturer of the equipment connected to the UPS.
Typically in-rush current is short enough (milliseconds) not to influence electrical installation (it does not trip the breaker). Typical breaker (type B) allows overload of 500% nominal current for some milliseconds (or even up to 1s). A UPS, as advanced power converter, is limited lower. Typically up to 200% for 200ms for professional UPS or up to 130% for few cycles in case of smaller online units. It is often not enough to acommodate the in-rush current.
If you plan to choose a UPS for your load, we advise to oversize the planned power capacity. Alternatively you can find appropriate inrush current limiter ( https://en.wikipedia.org/wiki/Inrush_current_limiter ).
