A tap conduct is to be connected to a feeder supplied by both a utility...

A tap conduct is to be connected to a feeder supplied by both a utility service source and a utility-interactive inverter source. The feeder utility source is a 400A breaker in a service panel, the inverter overcurrent protection device is rated at 100A, and the inverter continuous output current is 72. The tap conductor that is to be installed will be 17 ft. long. It will be located in a raceway and will supply a subpanel with a 50A main breaker.

What is the MINIMUM required ampacity of the tap conductor?