NEC Section 300.2: Use of Raceway for Multiple Circuits"Raceways shall not contain more than one circuit except as permitted in 300.3 or 300.5 through 300.
11."Exceptions



Section 300.3

Permits multiple circuits in the same raceway under certain conditions, such as when the raceway is large enough to accommodate all the conductors.

Sections 300.5 through 300.11

Provide specific exceptions for different types of circuits, such as remote-control, signaling, or power-limited circuits.

In this case

The scenario described in the question does not fall under any of the permitted exceptions. Therefore, running two different branch circuits through the same raceway from two different transformers would be a violation of NEC 300.2.

Reasons for the Requirement



Electrical Safety

Mixing circuits from different sources can create potential shock and fire hazards due to potential differences between the circuits.

Maintenance and Troubleshooting

Having multiple circuits in the same raceway can make it difficult to isolate and troubleshoot electrical issues.

Conductor Capacity

The raceway must have sufficient capacity to safely accommodate all the conductors and their associated insulation.

Possible Consequences



Electrical Shock

The presence of different voltages and currents in the same raceway can increase the risk of electrical shock to individuals working on or near the circuits.

Fire Hazard

Overloaded conductors or insulation damage can lead to overheating and potential fires.

Equipment Damage: Mixing circuits can interfere with the proper operation of equipment connected to the circuits. Flag for review