Live Tank circuit breakers and Dead tank circuit breakers

Live Tank circuit breakers are circuit breakers in which the interrupting chamber is at the line potential. The interrupting chamber should therefore be provided with insulated supports. The centre of gravity of these circuit breakers is higher, hence live tank circuit breakers need extra support for seismic capability (ability to withstand earthquakes)

In dead tank circuit breakers, the interrupting chamber is at ground potential.  The conductors enter the interrupting chamber through insulated bushings.  Maintenance activities are easier to conduct as the interrupting chamber is at ground level. Seismic capability is higher as the interrupting chambers are at ground level. 

Live Tank Circuit Breaker

Dead Tank Circuit Breaker