This Cutler Hammer R4H3030FJ rotary disconnect switch offers reliable performance for your electrical applications. Designed with a compact H frame, it features a 30 Amp, 3-pole configuration and is Class J fusible. It is suitable for 600V systems and includes test functionality..The Cutler Hammer R4H3030FJ is a 30 Amp, 3-pole rotary disconnect switch from the R9 Series. It is designed for 600V systems and utilizes Class J fuses. The switch features a compact H frame and DIN mounting. It also includes a test feature.