What is the difference between K=1 and K>1 breakers?

“K” is the voltage range factor. “K=1” means the short circuit current rating and the related required capabilities do not change with the operating voltage. In the past, breakers had a “K>1” (MVA) factor that meant the short circuit rating changed with voltage.

The new VCP-W K=1 breakers include additional features, such as capacitor switching.

VCP-W K=1 and K>1 (MVA) breakers are NOT interchangeable. If you have a K=1 breaker, you cannot put it into a cell designed for a K>1 (MVA) breaker, and vice versa.