A 200-amp panel upgrade requires service entrance conductors rated for 200-amp continuous service. The standard conductor sizes per NEC Table 310.12 are 4/0 AWG aluminum or 2/0 AWG copper for each of the two hot conductors, with 2/0 AWG aluminum or 1/0 AWG copper for the neutral. Most residential 200-amp service upgrades use aluminum SER (Service Entrance Round) cable because aluminum conductors at these large sizes are code-compliant per NEC 230.41 and cost approximately 30 to 40 percent less than equivalent copper for the same ampacity.
NEC 310.12: The Dwelling Service Exception
NEC Section 310.12 provides a dwelling unit service conductor sizing exception that is widely used for residential panel upgrades. Under this exception, the ungrounded service conductors for a 200-amp dwelling service may be 2/0 AWG aluminum or 1/0 AWG copper rather than the 4/0 AWG aluminum or 2/0 AWG copper that Table 310.16 alone would require. This exception is specific to the service entrance conductors between the meter base and the main panel in a single-family dwelling and does not apply to feeder conductors running to subpanels.
SER Cable vs Individual Conductors in Conduit
SER cable bundles the service entrance conductors in a single round jacket, simplifying installation and reducing the number of separate components. For a typical residential 200-amp service entrance, 4/0-4/0-2/0 aluminum SER (two 4/0 hot conductors and a 2/0 neutral, all aluminum) is the standard product. Alternatively, individual 4/0 AWG THHN aluminum conductors pulled through weatherhead conduit and Schedule 80 PVC conduit are also common, particularly when the utility or local code specifies individual conductors.
The Grounding Electrode Conductor
The panel upgrade also requires a grounding electrode conductor (GEC) connecting the main panel to the grounding electrode system (ground rods, water pipe ground, or concrete-encased electrode). For a 200-amp service, the GEC must be a minimum of 4 AWG copper per NEC Table 250.66. The GEC runs from the neutral bus in the main panel to the grounding electrode connection outside. This is a separate conductor from the service entrance conductors and is not part of the SER cable.
Permit and Utility Coordination Required
A 200-amp panel upgrade is a permitted project in every jurisdiction. The utility must disconnect the service at the weatherhead or meter base before work begins, which requires a utility appointment. Your licensed electrician coordinates the utility disconnect, pulls the permits, performs the upgrade, and schedules the inspection before power is restored. Do not attempt a panel upgrade without permits and utility coordination.
IB Lighting carries SER cable in standard 200-amp service sizes alongside THHN aluminum and copper conductors in all gauges. Browse our complete wire and cable selection or call (800) 674-9019 for contractor pricing on service entrance quantities. Free Freight Insurance Included.