ITE circuit breakers, BBC circuit breakers, ABB circuit breakers and ABB vacuum breakers
ITE circuit breakers were among the first manufactured and began production for the war effort around 1945. ITE air breakers were originally of the dashpot tripping design and mounted on large pieces of slate, which was considered the best non-conductive material at the time. ITE circuit breakers came in 480v, 5kv and 15kv designs. The original ITE air breaker line consisted of the KA, KB, KC, KD, KE 480v circuit breakers. The 5kv and 15kv ITE air circuit breakers were called 5-HV and 15- HV breakers. These ITE circuit breakers were made until the mid 1950s, with the introduction of the K Line and HK line of circuit breakers occurring at that time. The K and HK lines continued to be made into and throughout the early 1970s.
BBC Circuit Breakers purchased the ITE air circuit breaker line in the early 1970s. Brown Baverrie Corp continued to use the K line and HK line of circuit breakers until they were purchased by the ABB Company. BBC introduced the BBC LK circuit breaker, which was made for several years and subsequently discontinued.
ABB air circuit breakers continued with the K line at 480v, which consisted of the K-600, K-1600, K-2000, K-3000 and K-4000 ABB circuit breakers. ABB introduced different solid state trip units, continuing with the Powershield solid state trip unit and the introduction of the MPS solid state trip unit. ABB Circuit Breaker Company also introduced ABB vacuum circuit breakers into their 5kv and 15kv switchgear line. To this day, ABB vacuum circuit breakers are still in production.