Q. What is the Code rule regarding installing feeder and branch circuit conductors in the same raceway as service conductors?

A. Service conductors must not be installed in the same raceway or cable with feeder or branch circuit conductors [230.7]. Warning: Overcurrent protection for the feeder or branch circuit conductors can be bypassed if service conductors are mixed with feeder or branch circuit conductors in the same raceway and a fault occurs between the service and feeder or branch circuit conductors.

It's also important to note that this rule doesn't prohibit the mixing of service, feeder, and branch circuit conductors in the same service equipment enclosure.

This requirement may be the root of the misconception that "line" and "load" conductors must not be installed in the same raceway. It's true that service conductors must not be installed in the same raceway with feeder or branch circuit conductors, but line and load conductors for feeders and branch circuits can be in the same raceway or enclosure.