Type SE service-entrance cables shall be permitted in interior wiring systems where all the circuit conductors of the cable are of the ___ type.

• A. thermoset
• B. thermoplastic
• C. metal
• D. a or b

Answer: (D)

Interior wiring with Type SE cables requires that all circuit conductors use the same insulation type to ensure consistent heat and voltage performance. Type SE conductors can be insulated either with thermoset insulation or with thermoplastic insulation. If mixed insulation types were used within the same interior run, the different materials could react differently to heat, time, and temperature, potentially compromising insulation integrity. Because both thermoset and thermoplastic insulation types are acceptable, as long as every conductor in the cable is the same type, the correct condition is that all circuit conductors are of the same type, either thermoset or thermoplastic.