Can non-service conductors be installed in the same raceway as service conductors?

• A. Yes
• B. No
• C. Only if shielded
• D. Only if insulated

Answer: (B)

Service conductors carry the supply from the utility to the building’s service equipment and are protected and heat-rated for that source. Placing non-service conductors in the same raceway can create extra heat, complicate overcurrent protection, and make service equipment maintenance and fault handling more difficult. Keeping service conductors in their own raceway helps ensure proper heat dissipation and easier protection coordination, which is why non-service conductors should not be installed in the same raceway as service conductors. Shielding or insulating the other conductors wouldn’t address the heat and protection concerns, so those options aren’t acceptable.