The quick answer
For a standard 200 amp residential service, run 2/0 AWG copper or 4/0 AWG aluminum. Most homes actually use aluminum, so the cable you'll usually buy is 4/0-4/0-2/0 aluminum SER (two 4/0 hots and a 2/0 neutral).
House with a 200 amp panel? 2/0 copper or 4/0 aluminum for the two hot conductors. If a source tells you 3/0 copper, it's quoting the commercial number — legal, but a size bigger and more expensive than your house needs. The next section explains exactly why.
Why it's 2/0 copper, not 3/0 (the 310.12 dwelling rule)
This is the part almost every other guide gets wrong. There's a special NEC rule for homes: 310.12, often called the 83% rule. It lets the main service conductors (and the main feeder) that carry a dwelling's entire load use wire rated for just 83% of the service rating, because a house never actually pulls its full rated amperage continuously.
Run the math for a 200 amp service:
- 200 A × 83% = 166 A — that's the ampacity your wire actually has to have.
- Look up 166 A in the 75°C column: 2/0 copper carries 175 A and 4/0 aluminum carries 180 A — both clear 166 A.
- So a 200 amp home service is legal on 2/0 copper / 4/0 aluminum, one size smaller than a commercial feeder.
That single rule is why the wire behind almost every 200 amp residential meter in the country is 2/0 copper or 4/0 aluminum — and why paying for 3/0 copper on a normal house is usually money spent on a size you don't need.
When you actually use 3/0 copper (the standard value)
The 83% rule only applies to dwellings, on the conductors carrying the whole load. Step outside that and you're back to the full ampacity table, NEC 310.16, where 200 amps needs 3/0 copper (200 A) or 250 kcmil aluminum (205 A) at 75°C.
| Situation | Copper | Aluminum |
|---|---|---|
| Home service / main feeder (310.12, 83%) | 2/0 AWG | 4/0 AWG |
| Commercial or non-dwelling (Table 310.16) | 3/0 AWG | 250 kcmil |
You'd use the 3/0 column for a commercial 200 amp service, a sub-feed that doesn't carry the full dwelling load, or any time your local inspector (AHJ) specifically asks for full-table sizing. When in doubt, ask the AHJ before you buy — it's a one-question phone call that can save a size either way.
200 amp service wire chart
Every conductor in a typical 200 amp residential service, in one place:
| Conductor | Copper | Aluminum |
|---|---|---|
| Hot conductors (dwelling, 310.12) | 2/0 AWG | 4/0 AWG |
| Neutral (sized to load, 220.61) | often 1 size down | e.g. 2/0 on 4/0 SER |
| Grounding electrode conductor (250.66) | 4 AWG | 2 AWG |
| GEC to ground rods only (250.66(A)) | 6 AWG | 4 AWG |
The neutral (grounded conductor) doesn't have to match the hots — it's sized to the unbalanced 120-volt load under 220.61, which is why standard SER cable comes as 4/0-4/0-2/0: full-size hots, a smaller neutral.
100, 200 and 400 amp service wire (quick reference)
The same 310.12 dwelling rule sizes every residential service, so if you're comparing panels — or upgrading — here are the three common ratings side by side. Each is the 83% dwelling value, the size a normal house actually uses.
| Service | Copper (dwelling) | Aluminum (dwelling) |
|---|---|---|
| 100 amp | 4 AWG | 2 AWG |
| 200 amp | 2/0 AWG | 4/0 AWG |
| 400 amp | 400 kcmil | 600 kcmil |
These are the conductors that carry the whole service. Whether they run as SER cable through the wall or as individual THWN/XHHW conductors in conduit doesn't change the size — it only changes the cable type. A 200 amp upgrade from an older 100 amp panel, for example, steps the hots from 4 AWG copper all the way up to 2/0.
What size ground wire for a 200 amp service?
This is the second-most-asked question about 200 amp services, and it's confusing because "ground wire" can mean two different things. Let's separate them.
The grounding electrode conductor (GEC) — the wire from your panel to the ground rods, water pipe, or Ufer — is sized by NEC Table 250.66. For a 200 amp service with 2/0 copper conductors, that's 4 AWG copper.
There's a common allowance in 250.66(A): where the GEC connects only to a ground rod (or rods), it never has to be larger than 6 AWG copper, no matter the service size. So the wire to your ground rods can be #6, while the main GEC to a concrete-encased electrode (Ufer) is #4. Both are correct — they serve different electrodes.
Don't confuse the GEC with the neutral in the service cable — that's the third conductor sized under 220.61, not a "ground." Mixing them up is the single most common error in the ground-wire questions.
Copper vs aluminum for a 200 amp service
At service-entrance sizes, the cost gap between copper and aluminum is large, which is why 4/0 aluminum SER is what most homes are wired with. Copper (2/0) shows up where an installer prefers it, where terminations demand it, or on shorter runs where the price difference is small. Neither is "better" — both are code-compliant at the sizes above.
If you go aluminum, treat the connections properly: aluminum-rated lugs and breakers, an antioxidant compound on the terminations, and torque to the manufacturer's spec. Done right, aluminum service conductors have a long, reliable track record; done carelessly, loose aluminum terminations are a real hazard. For the underlying ampacity behind all of these numbers, see the full AWG ampacity chart.
Service entrance cable: SER, SEU, or conduit?
The 2/0 copper or 4/0 aluminum conductors reach your panel one of three common ways, and the wire size is the same in all of them — only the cable type changes with the path:
- SER (Service Entrance, Round) — a four-conductor cable with two hots, a neutral, and a bundled ground. Used for the main feeder from the disconnect to the panel, and for subpanels. This is the classic 4/0-4/0-2/0 aluminum SER.
- SEU (Service Entrance, U-shaped) — three conductors, no separate ground. Used from the meter to the main service disconnect, where the neutral is still bonded to ground.
- THWN / XHHW in conduit — individual conductors pulled through pipe for exposed, outdoor, or underground runs (underground typically uses USE/RHW-rated wire).
If you're going underground from a pad-mount transformer or a detached meter, the run is almost always individual conductors in conduit rather than cable. Your utility and local AHJ set the exact rules at the service point, so confirm the required type before you buy.
Meter to panel, and long runs (voltage drop)
The service-entrance run — meter base to main panel — is usually short, so the dwelling sizes above are all you need. Voltage drop only becomes a factor on a long feeder, like a 200 amp subpanel in a detached garage or shop far from the house.
2/0 copper → good to about 186 ft.
4/0 aluminum → good to about 180 ft. Past that on a long feeder, step the conductors up a size.
One thing to keep straight: the NEC sets no hard voltage-drop limit on a service or feeder — the 3% figure is a recommendation (an Informational Note), not a rule you can fail inspection on. It's still worth following on long runs so lights don't dim when the AC kicks on. The Voltage Drop Calculator checks your exact distance and load.
Common 200 amp service mistakes
The most expensive one is buying 3/0 copper when 2/0 is legal for a house — a full wire size of copper you didn't need. The opposite error is applying the 83% rule where it doesn't belong, like a non-dwelling service. After that it's grounding: undersizing the GEC, or confusing the grounding electrode conductor with the neutral. Aluminum installs fail when terminations aren't torqued or anti-oxidant is skipped. And the quiet one — assuming a national answer when your local AHJ has amended the code; always confirm locally before a service job.
Frequently asked questions
Service & CodeWhat size wire do I need for a 200 amp service?
⚡ Wire Size calculator →
Service & CodeIs 2/0 or 3/0 copper right for a 200 amp service?
Wire & CircuitWhat size aluminum wire for a 200 amp service?
Service & CodeWhat size ground wire for a 200 amp service?
Wire & CircuitCan I use 4/0 aluminum for a 200 amp service?
Service & CodeWhat is the 83% rule for service conductors?
Wire & CircuitHow far can I run 2/0 copper on a 200 amp service?
⚡ Voltage Drop calculator →
Service & CodeWhat size wire runs from the meter to the panel for a 200 amp service?
This guide is for general information based on the National Electrical Code. Local codes and your authority having jurisdiction (AHJ) may differ, and service work is often permit-and-inspection territory. Electrical work can be dangerous, so when in doubt, hire a licensed electrician.