ABB VD4 Series VCB: VD4 Medium voltage vacuum circuit-breakers 12…24 kV – 630…3150 A – 16…40 kA. The new VD4 is a synthesis of the renowned technology in designing and constructing vacuum interrupters embedded in resin poles and of excellence in design, engineering, and production of circuit-breakers. The VD4 medium voltage circuit breakers use vacuum interrupters embedded in resin poles. Embedding the interrupter in resin makes the circuit-breaker poles particularly sturdy and protects the interrupter against shocks, accumulation of dust, and humidity. The vacuum interrupter houses the contacts and makes up the interrupting chamber. Ready stock available