Wire Size for a 200-Amp Service: 2026 NEC Guide

A 200-amp residential service requires 2/0 copper or 4/0 aluminum service-entrance conductors under the NEC dwelling-service rule, 310.12. These sizes look small next to the full Table 310.16 values because a single-phase dwelling service is allowed to be sized at 83 percent of the rating. A 200-amp feeder or sub-panel that is not a service is sized differently, and confusing the two is the most common mistake. This guide explains the service conductor size, the grounding-electrode conductor, cable types, and why a service upgrade is a permit-and-electrician job.

200-Amp Service Wire Size Quick Reference

The 310.12 Dwelling-Service Rule

For a one-family dwelling or the individual unit of a two-family dwelling, NEC 310.12 lets the main service conductors be sized at 83 percent of the service rating rather than the full Table 310.16 ampacity. For a 200-amp service, 83 percent is 166 amps, and the conductor that covers that is 2/0 copper, rated 175 amps at 75 degrees, or 4/0 aluminum, rated 180 amps. That is why electricians say 2/0 copper or 4/0 aluminum for a 200-amp house service, even though those same conductors would be rated below 200 amps for an ordinary feeder. The allowance exists because a home rarely draws its full service rating, and decades of data support it. This rule applies only to the main service and to a feeder that carries the entire load of a dwelling, not to general feeders or sub-panels.

Service Versus Feeder: Do Not Mix Them Up

This is where projects go wrong. If you are sizing the conductors from the meter to the main 200-amp panel of a house, the 310.12 dwelling rule applies and you use 2/0 copper or 4/0 aluminum. If you are sizing a 200-amp feeder to a sub-panel that does not carry the whole dwelling load, or any non-dwelling 200-amp feeder, the 310.12 allowance does not apply and you size from the full Table 310.16, which calls for 3/0 copper or 250 kcmil aluminum at 75 degrees. The two answers differ by a full wire size, and using the smaller service-rated conductor on an ordinary feeder is a code violation. Always ask first whether the conductor is a dwelling service main or a feeder, because the same 200-amp number maps to different wire.

Cable and Conduit for the Service

Above-ground service-entrance conductors from the meter to the panel are commonly run as SE cable, a 2/0 copper or 4/0 aluminum SE-style cable rated for the job, or as individual conductors in conduit. For an underground service lateral from a pad-mount transformer or a meter pedestal, the conductors are USE-2 or XHHW-2 rated for wet and direct-burial conditions, pulled through PVC conduit. The exact configuration is often dictated by the local utility, which has its own service requirements for the meter base, conduit size, and where their responsibility ends and yours begins. Because the service conductors are unprotected by an overcurrent device until they reach the main breaker, they must be installed exactly to code and utility spec, which is one reason this work is not a typical DIY project.

Grounding and Bonding a 200-Amp Service

A 200-amp service needs a grounding-electrode system: typically two ground rods spaced at least six feet apart, plus a connection to the metal water pipe within five feet of entry if present, and a concrete-encased electrode (Ufer) in new construction. The grounding-electrode conductor for a 200-amp service is 4 AWG copper or 2 AWG aluminum per NEC Table 250.66, sized to the service conductors. The main bonding jumper bonds the neutral to the enclosure at the service disconnect, the one and only place neutral and ground are tied together in the entire system. The main panel is also where the neutral-ground bond lives, every downstream sub-panel keeps them separate. Getting the electrode system and the main bonding jumper right is essential, because they are what clears a fault and keeps the system safe.

What a Service Upgrade Actually Involves

Upgrading to a 200-amp service is more than swapping a panel. It involves coordinating with the utility to disconnect and reconnect power, installing a new meter base and main panel, pulling the correct service conductors, building the grounding-electrode system, and passing both a utility and an AHJ inspection. Permits are required everywhere, and most jurisdictions do not allow homeowners to perform service work without a license because of the lethal, unprotected nature of the service conductors. Typical costs run from 1,800 to 4,000 dollars or more depending on whether the meter location moves, whether the service is overhead or underground, and local labor rates. If you are upgrading to support an EV charger, heat pump, or shop, 200 amps is the common target, though a load calculation occasionally points to 150 amps as sufficient or 320 or 400 amps for larger demands.

Planning Loads for a 200-Amp Service

A 200-amp service supplies roughly 48,000 watts at 240 volts, which comfortably handles a typical all-electric home with central air, an electric range, electric water heating, a dryer, and a Level 2 EV charger when loads are reasonable. The right way to confirm 200 amps is enough is an NEC Article 220 load calculation, which adds the general lighting and receptacle load, the appliance loads, the largest of heating or cooling, and any EV or special equipment, applying the standard demand factors. Modern electrification, multiple EVs, a heat pump, and an induction range together can approach the limit, in which case load-management devices or a larger service come into play. Running the numbers before the upgrade avoids both under-building and paying for capacity you will never use.

Electrical work carries safety and legal risk. Verify any calculation with a licensed electrician familiar with your local code amendments before performing work. This article references NEC 2023; many jurisdictions still operate under NEC 2017 or 2020 or have local amendments, so always confirm with your local AHJ.

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Data sources: NEC 2023 (NFPA 70) Table 310.16, 240.4(D), 310.12, and Article 250; NFPA 70 Handbook 2023; manufacturer termination ratings; r/electricians field reports. Written by Munir Afridi, VoltFlow editorial team.