... reasonable design CFW series high-intensive sealed insulating bus duct is ideal to be used in the ... 220V, 380V, 660V2. Rated frequency: 50/60Hz3. Rated current: 100,200,250,400,630,800,1000,1250,1600,2000 ... less than 20M ohm.5. Insulating intension: every bus duct will need to be under the test ... stress and electrodynamic force created by tolerance current.. High Intensive Sealed Insulating Bus Duct