... , beautiful appearance. and reasonable design CFW series high-intensive sealed insulating bus duct is ideal to be used in the equipment ... ,2000,2500,3150,4000,5000A.4. Insulating resistance: under normal working condition, the value of insulating resistance between phase and shell and ... the phases should be no less than 20M ohm.5. Insulating intension: every bus duct will need to be under the ...