Feeder or branch circuit wiring is not allowed in the same raceway/conduit as service conductors. The reason is that service conductors (wires) do not have overcurrent protection, so a short between a service conductor and a feeder or branch circuit conductor in the same conduit would not trip a breaker and is a fire hazard.

    But feeder and branch circuit wiring are allowed in the same conduit because they occur after the main breaker and have overcurrent protection in the event of a short. In a residence with an outside service panel and an interior subpanel for distribution, it’s important to recognize the difference between the service conductors coming in from the meter and the feeder conductors that run to the subpanel inside the home. Either of them can come into the panel at the top, bottom, or side of the panel. Both are often the same size wiring, but the service conductors are connected to the main breaker. 

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Here’s links to a collection of our other blog posts about ELECTRIC PANELS: 

• What is the maximum number of circuit breakers allowed in an electric panel?

• When should a corroded or damaged electric panel cabinet or disconnect box be replaced? 

• What is a tandem circuit breaker? 

• When did arc fault circuit interrupter (AFCI) breakers first become required?

• Can you add circuit breakers by different manufacturers to an electric panel if they fit?

• My circuit breaker won't reset. What's wrong?  

• What is a split bus electric panel?

• What is the maximum gap allowed between the front of a recessed electric panel box and the wall surface surrounding it? 

• What are the requirements for NM-cables entering an electric panel box?

• Why is a fuse box/panel an insurance problem for homebuyers? 

• Why is bundled wiring in an electric panel a defect?

• What is the difference between GFCI and AFCI circuit breakers? 

• What is the difference between "grounded" and "grounding" electrical conductors? 

• What does it mean when a wire is "overstripped" at a circuit breaker? 

• Who is the manufacturer of those "bad" electric panels?

• What is a double tap at a circuit breaker?

• What is the right electric wire size for a circuit breaker in an electric panel?

• What is the life expectancy of a circuit breaker? 

• What is the right size electric panel for a house? 

• What do I need to know about buying a whole house surge protector? 

• What is the maximum height you can mount an electric panel above the floor? 

• What is the code required clearance in front of an electric panel?

• What is the main bonding jumper and where do it find it in an electric panel? 

   Visit our ELECTRIC PANELS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.