The powerful 3AH3 vacuum circuit breakers were the first 63- and 72-kA vacuum circuit breakers on the market tested in accordance with IEEE C37.013 for load currents up to 12,000 A and short-circuit currents up to 100 kA. In addition to the standard designs, we can also offer phase-segregated versions with separate switching units. The low resistance in the main current path allows the 3AH3 vacuum circuit breaker to be used with operating currents of up to 6,300 A with no forced cooling, or up to 8,000 A with forced cooling. These modular vacuum circuit breakers can also be installed horizontally using special cooling elements and are suitable for retrofitting in existing systems.