What Size Wire for 200 Amp Service: Essential Electrical Sizing Requirements

Understanding what size wire for 200 amp service installations require is absolutely critical for both safety and code compliance in residential and commercial electrical systems. The proper wire sizing ensures your electrical service can safely handle the amperage load without overheating, voltage drop issues, or creating fire hazards. This comprehensive guide examines every aspect of selecting, installing, and understanding the correct wire specifications for 200 amp electrical services, including detailed comparisons of different wire types, installation scenarios, and regulatory requirements that electricians and property owners need to know.

Table of Contents

Understanding 200 Amp Service Wire Requirements

When determining what size wire for 200 amp service installations, the primary answer depends on whether you’re using copper or aluminum conductors. For copper wire, you’ll need 2/0 AWG (American Wire Gauge) for a 200 amp service. For aluminum or copper-clad aluminum wire, which is more commonly used due to cost considerations, you’ll need 4/0 AWG. These specifications are established by the National Electrical Code (NEC) and are designed with safety margins to prevent conductor overheating under maximum load conditions.

The wire size requirements for 200 amp service are specifically calculated based on the ampacity ratings of different conductor materials and types. Ampacity refers to the maximum amount of electrical current a conductor can carry before exceeding its temperature rating. For residential 200 amp services, the service entrance conductors must be sized to handle the full 200 amperes continuously, though actual household loads rarely approach this maximum. The NEC requires that service conductors be sized at 83% of their rated ampacity for continuous loads, which influences the final wire gauge selection. Understanding these fundamental requirements helps prevent costly installation errors and ensures long-term electrical system reliability.

Key Wire Sizing Specifications

Wire Material	Minimum Wire Size	Ampacity Rating	Temperature Rating
Copper	2/0 AWG	200A at 75°C	75°C (167°F)
Aluminum	4/0 AWG	200A at 75°C	75°C (167°F)
Copper-Clad Aluminum	4/0 AWG	200A at 75°C	75°C (167°F)

The temperature rating of wire insulation is equally important when sizing conductors for 200 amp electrical service. Most residential applications use THHN/THWN insulation rated for 75°C in wet locations and 90°C in dry locations. However, termination points at breakers and panels are typically rated for 75°C, which means you must size conductors based on the 75°C ampacity column in NEC tables, even if the wire itself can handle higher temperatures. This is a critical distinction that many DIY installers miss, potentially leading to overheated connections and electrical failures. Professional electricians always verify that both the conductor size and insulation type match the specific installation environment and local code requirements.

Copper vs Aluminum Wire for 200 Amp Service

The choice between copper and aluminum conductors for what size wire for 200 amp service installations significantly impacts both installation costs and long-term performance. Copper wire, while more expensive, offers superior conductivity, requiring smaller physical dimensions for the same ampacity. The 2/0 AWG copper wire needed for 200 amp service is significantly easier to work with than the bulkier 4/0 AWG aluminum wire, making installation in tight spaces more manageable. Copper also resists corrosion better than aluminum and creates more reliable connections at termination points, which is why many electricians prefer it despite the higher material costs.

Aluminum wire presents specific challenges that must be addressed during installation to ensure safe, reliable electrical service. Aluminum oxidizes when exposed to air, creating a resistant layer at connection points that can lead to overheating if not properly treated with anti-oxidant compound. Additionally, aluminum expands and contracts more than copper with temperature changes, which can cause connections to loosen over time if not properly torqued and maintained. Modern aluminum wire installations require special connectors rated for aluminum use, anti-oxidant paste at all terminations, and specific torque specifications that exceed those for copper connections. These additional requirements increase installation complexity and time, though aluminum remains popular for service entrance conductors due to its significant cost savings over copper, often 50-70% less expensive for equivalent ampacity.

Cost Comparison Analysis

Copper 2/0 AWG wire: $3.50-$5.00 per foot (varies by market conditions)
Aluminum 4/0 AWG wire: $1.50-$2.50 per foot
Typical 200 amp service run (100 feet): Copper $350-500 vs Aluminum $150-250
Total installation cost difference: $200-250 in materials alone

The weight difference between copper and aluminum conductors also impacts installation labor costs and physical handling requirements. Aluminum 4/0 AWG wire is significantly lighter than copper 2/0 AWG, making it easier to pull through conduit and reducing physical strain on installers. However, this advantage is partially offset by the need for larger conduit sizes to accommodate the greater diameter of aluminum conductors. A typical 200 amp service using aluminum wire requires 2-inch conduit, while copper can often fit in 1.5-inch conduit, affecting both conduit costs and installation flexibility. These factors must be weighed against the material cost savings when determining the most economical choice for specific installations.

Wire Sizing Based on Installation Distance

Distance calculations play a crucial role when determining what size wire for 200 amp service because voltage drop becomes increasingly problematic over longer runs. The NEC recommends limiting voltage drop to 3% for feeder circuits and 5% total for both feeder and branch circuits combined. For 200 amp services, this typically means that runs exceeding 100-150 feet may require upsizing the conductors to maintain adequate voltage at the panel. Voltage drop occurs because all conductors have resistance, and when current flows through resistance, energy is converted to heat and the voltage available at the far end decreases.

Calculating voltage drop for 200 amp service wire installations requires considering the actual load amperage, not just the service rating. A 200 amp service rarely carries the full 200 amperes continuously, with typical residential loads averaging 80-120 amperes during peak usage. For a 120-foot run carrying 100 amperes, using copper 2/0 AWG wire on a 240-volt service results in approximately 2.4% voltage drop, which is acceptable. However, the same run with 150 amperes would produce 3.6% voltage drop, exceeding recommendations and potentially requiring an upgrade to 3/0 AWG copper or 250 kcmil aluminum to reduce resistance and maintain proper voltage levels throughout the electrical system.

Voltage Drop Calculation Table

Distance (feet)	Load (amps)	Copper Wire Size	Aluminum Wire Size	Voltage Drop %
50	200	2/0 AWG	4/0 AWG	1.2%
100	200	2/0 AWG	4/0 AWG	2.4%
150	200	3/0 AWG	250 kcmil	2.7%
200	200	4/0 AWG	300 kcmil	2.8%

When installations require particularly long runs from the utility transformer to the main panel, electricians must carefully calculate the combined resistance of both the hot conductors and account for the specific service voltage. For single-phase 240-volt services, both hot conductors contribute to voltage drop, effectively doubling the circuit length in resistance calculations. This is why the voltage drop formula includes a factor of 2 for the round-trip distance. Professional installers use specialized voltage drop calculators or reference tables that account for conductor material, temperature coefficients, and actual installation conditions to ensure calculations reflect real-world performance rather than theoretical values.

Conduit Requirements for 200 Amp Service Wire

Selecting appropriate conduit size for what size wire for 200 amp service installations ensures proper wire protection and meets NEC fill capacity requirements. The conduit must be large enough to accommodate all service conductors plus the grounding conductor without exceeding 40% fill for three or more conductors. For copper 2/0 AWG service entrance conductors (two hots, one neutral, one ground), a minimum of 1.5-inch conduit is typically required, though many electricians prefer 2-inch conduit to ease wire pulling and allow for future modifications. Aluminum 4/0 AWG conductors always require 2-inch minimum conduit due to their larger physical diameter.

The type of conduit also affects installation requirements and long-term durability for 200 amp electrical service. PVC conduit is popular for underground installations due to its corrosion resistance and lower cost, though it requires expansion fittings on long runs to accommodate thermal expansion and contraction. Rigid metal conduit (RMC) provides superior mechanical protection and is often required for exposed outdoor installations or areas subject to physical damage. Electrical metallic tubing (EMT) offers a lighter-weight alternative for protected indoor installations and is easier to bend and install than rigid conduit, though it provides less mechanical protection. Each conduit type has specific fill tables in the NEC that must be consulted to ensure proper sizing based on the number and size of conductors being installed.

Conduit Sizing Requirements

For Copper 2/0 AWG (3 conductors + ground):

PVC Schedule 40: 1.5-inch minimum (2-inch recommended)
EMT: 1.5-inch minimum (2-inch recommended)
Rigid Metal Conduit: 1.5-inch minimum

For Aluminum 4/0 AWG (3 conductors + ground):

PVC Schedule 40: 2-inch minimum (2.5-inch for easier pulling)
EMT: 2-inch minimum
Rigid Metal Conduit: 2-inch minimum

Proper conduit installation techniques significantly impact the ease of wire pulling and long-term system reliability. Conduit runs should minimize the number of bends, as each 90-degree bend increases pulling difficulty and limits the number of additional bends allowed before an intermediate pull box is required. The NEC limits conduit runs to 360 degrees of total bends (equivalent to four 90-degree bends) between pull points. For 200 amp service installations with large conductors, exceeding even two 90-degree bends often makes pulling prohibitively difficult without wire lubricant and mechanical assistance. Strategic placement of pull boxes at logical bend points reduces installation time and prevents conductor damage from excessive pulling tension.

Ground Wire Requirements for 200 Amp Service

Understanding ground wire sizing for what size wire for 200 amp service is essential for electrical safety and code compliance. The grounding electrode conductor (GEC) connects the service panel to the grounding electrode system, which typically includes ground rods, water pipes, or other approved grounding methods. For 200 amp service, the NEC requires a minimum 4 AWG copper or 2 AWG aluminum grounding electrode conductor when connected to a ground rod. However, if the service is grounded to a concrete-encased electrode (Ufer ground) or metal water pipe, the minimum size increases to 4 AWG copper regardless of the grounding electrode type.

The equipment grounding conductor, which runs with the service entrance conductors, has different sizing requirements than the grounding electrode conductor. For 200 amp service, the equipment grounding conductor must be sized according to NEC Table 250.122, which specifies 6 AWG copper or 4 AWG aluminum as the minimum size. This conductor provides the fault current path back to the source and must be large enough to safely carry fault currents without overheating until the overcurrent protection device operates. Many electricians install larger equipment grounding conductors than the minimum required to provide additional safety margin and accommodate potential future service upgrades without needing to replace the grounding system.

Grounding System Components

Grounding Electrode Conductor (GEC): 4 AWG copper minimum to ground rod
Equipment Grounding Conductor: 6 AWG copper minimum (runs with service conductors)
Grounding Electrode: Two ground rods minimum, 8 feet long, 6 feet apart
Bonding Jumper: Connects neutral bus to panel enclosure, same size as GEC

The connection methods for grounding conductors require specific attention to ensure reliable electrical bonding. Ground rod connections must use approved clamps that are listed for direct burial and resist corrosion. The GEC connection to the service panel must be made with a bonding screw or listed grounding bar, and the neutral bus must be bonded to the panel enclosure at the service entrance (but never at subpanels). Water pipe grounding requires bonding on both sides of the water meter to maintain continuity if the meter is removed, and the connection must be made to the metallic water pipe within 5 feet of where it enters the building. These detailed grounding requirements ensure that fault currents have a reliable, low-impedance path to ground, enabling protective devices to operate quickly during fault conditions.

Single Phase vs Three Phase 200 Amp Service Wire Sizing

The distinction between single-phase and three-phase installations significantly affects what size wire for 200 amp service you’ll need. Most residential 200 amp services use single-phase power, requiring two hot conductors (typically black and red), one neutral conductor (white or gray), and one equipment grounding conductor (green or bare). The hot conductors must each be sized for the full 200 amp rating (2/0 copper or 4/0 aluminum), while the neutral is sized based on the maximum unbalanced load, though it’s typically the same size as the hot conductors for service entrance applications to handle potential imbalances and provide adequate current-carrying capacity.

Three-phase 200 amp services, more common in commercial and industrial settings, require three hot conductors plus neutral and ground. The individual conductor sizing remains the same (2/0 AWG copper or 4/0 AWG aluminum per hot conductor), but the total installation cost increases due to the additional hot conductor and larger conduit required to accommodate four large conductors instead of two. Three-phase services distribute power more evenly and efficiently for large motor loads and commercial equipment, but they’re rarely necessary for standard residential applications unless the property includes significant three-phase equipment like large air compressors, commercial kitchen equipment, or industrial machinery.

Phase Configuration Comparison

Single-Phase 200A Service:

2 hot conductors (L1, L2) – each 2/0 Cu or 4/0 Al
1 neutral conductor – 2/0 Cu or 4/0 Al
1 ground conductor – 6 AWG Cu or 4 AWG Al
Supply voltage: 120/240V
Typical application: Residential, small commercial

Three-Phase 200A Service:

3 hot conductors (L1, L2, L3) – each 2/0 Cu or 4/0 Al
1 neutral conductor – 2/0 Cu or 4/0 Al
1 ground conductor – 6 AWG Cu or 4 AWG Al
Supply voltage: 120/208V or 277/480V
Typical application: Commercial, industrial

The load calculation methods differ between single-phase and three-phase services, affecting how installers determine whether the 200 amp service wire size is adequate for the planned electrical demand. Single-phase load calculations sum all 120-volt and 240-volt loads with appropriate demand factors applied per NEC Article 220. Three-phase calculations must account for the load distribution across all three phases and consider whether loads are line-to-neutral (single-phase) or line-to-line (three-phase). Unbalanced three-phase loads can result in excessive neutral current, potentially requiring neutral conductors to be sized larger than the phase conductors in some situations. Professional electrical designers use specialized software to perform these calculations accurately and ensure the installed service capacity meets both current and anticipated future electrical demands.

Installation Methods and Wire Types

The installation method significantly influences what size wire for 200 amp service installations and what type of wire insulation is required. Underground service installations typically use USE-2 (Underground Service Entrance) or RHW-2 (Rubber High Water Resistance) conductors, which are specifically rated for direct burial or installation in underground conduit. These wire types feature moisture-resistant insulation that prevents degradation from soil moisture and are rated for continuous exposure to temperatures up to 90°C, though conductor ampacity is still calculated based on 75°C terminal ratings. Direct burial installations without conduit require conductors rated for direct earth contact and installation at depths specified by local codes, typically 24 inches minimum for residential services.

Overhead service installations from the utility pole to the building use different wire types optimized for aerial exposure. Triplex or quadruplex service drop cable combines the hot conductors and neutral into a single assembly with weather-resistant insulation that can withstand UV exposure, wind loading, and temperature extremes. These cables are supported by a separate messenger wire or use one conductor as the structural support member. The conductors within service drop cable must still meet the same ampacity requirements (2/0 copper or 4/0 aluminum for 200 amp service), but the overall assembly is designed for the mechanical stresses of aerial installation. The attachment point at the building must be at least 10 feet above ground (higher for areas with vehicle traffic) and use proper strain relief to prevent stress on the service entrance conductors where they transition into the meter base.

Common Wire Insulation Types

THHN/THWN: Thermoplastic High Heat Nylon-coated, rated 90°C dry/75°C wet, most common for conduit
XHHW: Cross-linked High Heat Water-resistant, rated 90°C dry/75°C wet, more flexible than THHN
USE-2: Underground Service Entrance, rated 90°C, approved for direct burial
RHW-2: Rubber High Water-resistance, rated 90°C wet, durable in harsh environments
SER: Service Entrance Round, combines conductors in single jacket, common for interior service runs

The physical routing of service entrance conductors impacts both installation difficulty and code compliance. Service conductors must be protected from physical damage throughout their entire run, requiring conduit or cable assemblies rated for the installation environment. Transitions between installation methods (such as from underground to aerial or from exterior to interior) require special attention to sealing and mechanical protection. Service entrance conductors entering buildings through foundations must be sealed to prevent water and pest infiltration, and the conduit must be supported within 3 feet of all terminations and at intervals not exceeding 8-10 feet depending on conduit type. These installation details, while seemingly minor, significantly affect system longevity and reliability over the 25-30 year typical service life of residential electrical systems.

Meter Base and Service Panel Compatibility

Ensuring meter base compatibility with your selected 200 amp service wire is critical for successful installation. Meter bases rated for 200 amp service must have terminals capable of accepting 2/0 copper or 4/0 aluminum conductors, and the terminal torque specifications must be strictly followed during installation. Under-torqued connections lead to high resistance, heat buildup, and eventual failure, while over-torqued connections can damage the terminal block or strip threads on the terminal screws. Most modern meter bases designed for 200 amp service include labeled terminals clearly marked for line and load connections, with separate lugs for the grounding and neutral conductors that must be properly bonded within the meter enclosure.

The service panel or load center receiving power from the meter base must also be rated for 200 amp service and compatible with the conductor type being installed. Panels rated for aluminum conductors include terminals specifically designed for aluminum wire and marked “AL” or “CU/AL” to indicate dual compatibility. Using aluminum conductors on terminals rated only for copper violates electrical codes and creates serious safety hazards. The main breaker within the panel must be rated for 200 amps and compatible with the panel bus bar design. Some panels use bolt-on main breakers, while others use plug-in designs, and the breaker type must match the panel manufacturer’s specifications to ensure proper mechanical and electrical connection.

Service Equipment Specifications

200 Amp Meter Base Requirements:

Terminal rating: 2/0 Cu or 4/0 Al minimum
Terminal torque: 200-250 inch-pounds (verify manufacturer specs)
Hub size: 2-inch minimum for service conduit entry
Weatherproof rating: NEMA 3R minimum for outdoor installation
Bypass provision: Optional for utility meter maintenance

200 Amp Service Panel Requirements:

Bus bar rating: 200 amps continuous
Main breaker: 200 amp rated (AIC rating appropriate for fault current)
Branch circuit positions: Minimum 40 spaces recommended for residential
Ground bar: Bonded to enclosure at service entrance only
Working clearance: NEC requires 30 inches width, 36 inches depth, 78 inches height

The physical installation location of both meter base and service panel affects accessibility, safety, and code compliance. The meter base must be installed at a height convenient for utility personnel to read, typically 4-6 feet to the center of the meter socket. The service panel should be located as close as practical to the meter base to minimize conductor length and voltage drop, though it must be installed in an area providing the required working clearances. NEC Article 110.26 specifies that electrical panels must have 36 inches of clear space in front, extending the full width of the panel and 78 inches high, with no storage or obstructions permitted in this zone. Many jurisdictions also require the main service disconnect to be located on the outside of the building or immediately inside the service entrance to provide first responders with a readily accessible means to disconnect building power during emergencies.

Common Wire Sizing Mistakes to Avoid

One of the most frequent errors when determining what size wire for 200 amp service involves confusing service entrance conductors with feeder conductors. Service entrance conductors connect the utility meter to the main service panel and must be sized for the full 200 amp rating without applying standard derating factors. Feeder conductors, which run from the main panel to subpanels, are sized based on the calculated load of the circuits they supply, which is often significantly less than 200 amps. Installing undersized feeder conductors to a subpanel is dangerous and violates code, but using the full 200 amp service entrance conductor size for short feeder runs is wasteful and unnecessarily expensive. Proper load calculations determine the appropriate feeder size based on actual demand.

Another critical mistake involves failing to account for temperature derating when conductors are installed in high-temperature environments or in conduits containing multiple current-carrying conductors. While the base ampacity of 2/0 copper is 200 amps at 75°C, this rating assumes specific installation conditions. If the ambient temperature exceeds 86°F (30°C), or if more than three current-carrying conductors share the conduit, derating factors must be applied that reduce the effective ampacity. For example, if your 200 amp service conductors run through an attic where temperatures reach 130°F (54°C), the temperature correction factor of 0.82 reduces the effective ampacity of 2/0 copper to 164 amps, requiring an upgrade to 3/0 to maintain 200 amp capacity. Ignoring these derating requirements leads to conductor overheating and creates serious fire hazards.

Critical Installation Errors

Using aluminum-rated terminals with copper wire or vice versa – Terminals must match conductor material
Improper grounding electrode connections – Ground rod clamps must be listed for direct burial
Insufficient conduit fill calculation – Exceeding 40% fill makes wire pulling difficult and violates code
Missing anti-oxidant compound on aluminum connections – Leads to high-resistance connections and overheating
Incorrect terminal torque – Both under-torquing and over-torquing cause connection failures
Neglecting voltage drop calculations – Long runs require upsizing to maintain adequate voltage
Mixing wire types in same conduit – All conductors must have compatible temperature ratings
Improper neutral sizing – Neutral must handle maximum unbalanced load plus any harmonic currents

The consequences of these installation errors range from minor code violations caught during inspection to catastrophic failures resulting in fires or electrocution hazards. Professional electricians invest significant time in training and code education to avoid these mistakes, and they understand that taking shortcuts during installation creates liability exposure and endangers building occupants. Homeowners considering DIY electrical work for 200 amp service installations should seriously reconsider this approach, as the complexity, safety requirements, and permit/inspection processes make this work highly unsuitable for non-professionals. Most jurisdictions specifically prohibit unlicensed individuals from performing service entrance electrical work, and insurance policies may deny claims for damages resulting from unpermitted electrical installations.

Permit and Inspection Requirements

All 200 amp service installations require electrical permits from the local building authority regardless of whether the work is performed by a licensed electrician or the property owner. The permit process typically involves submitting detailed plans showing the service entrance location, conductor sizes, panel specifications, and grounding system details. Permit fees vary by jurisdiction but typically range from $150-500 for residential 200 amp service installations. The permit application may require proof of liability insurance if the work is being performed by a contractor, and some jurisdictions mandate that only licensed electrical contractors can perform service entrance work, prohibiting homeowner installations even with permits.

The inspection process for what size wire for 200 amp service installations occurs in multiple stages to ensure code compliance at each critical point. The rough-in inspection occurs after conduits and cables are installed but before they’re concealed by walls or buried underground, allowing the inspector to verify proper conduit sizing, conductor types, and routing. The final inspection happens after all connections are completed and the service is energized, verifying proper conductor sizing, terminal connections, panel labeling, grounding system installation, and working clearances. Failed inspections require corrections before the electrical service can be legally used, and utilities typically won’t provide permanent service connection until receiving approval from the local building department.

Inspection Checklist Items

Rough-In Inspection Verification:

Conduit size and type appropriate for conductors
Proper conductor type for installation method (USE-2 for underground, etc.)
Correct wire gauge (2/0 Cu or 4/0 Al for 200A)
Grounding electrode system properly installed
Service entrance location meets clearance requirements
Conduit properly supported and sealed at entries

Final Inspection Verification:

Terminal connections properly torqued
Anti-oxidant compound applied to aluminum connections
Neutral and ground properly bonded at service entrance
Panel properly labeled with circuit directory
Required working clearances maintained
Ground fault and arc fault protection where required
Proper disconnect means provided

Building departments maintain inspection records that become part of the property’s permanent file and can affect future property transfers, insurance coverage, and liability in the event of electrical fires or accidents. Work performed without permits and inspections, even if technically correct, creates significant legal and financial risks for property owners. Some insurance companies specifically exclude coverage for damages caused by unpermitted electrical work, and sellers may be required to disclose unpermitted improvements during property sales, potentially affecting market value. These considerations make obtaining proper permits and passing inspections essential components of any 200 amp service wire installation project, protecting both the immediate safety of occupants and the long-term value of the property.

Upgrading from 100 Amp to 200 Amp Service

Many homeowners find themselves needing to understand what size wire for 200 amp service when upgrading from an existing 100 amp service that can’t handle modern electrical demands. Homes built before 1960 typically have 60-100 amp service, which was adequate for the limited electrical loads of that era but struggles to support today’s HVAC systems, electric vehicle chargers, and multiple high-wattage appliances operating simultaneously. The upgrade process involves replacing the meter base, service panel, service entrance conductors, and often the grounding system to meet current code requirements, representing a significant investment typically ranging from $2,500-6,000 depending on installation complexity and regional labor rates.

The service upgrade process requires careful planning to minimize disruption to building occupants. The utility company must be notified to schedule disconnection and reconnection of power, which typically requires a full day without electricity. During this time, the electrical contractor removes the old meter base and installs the new 200 amp rated equipment, pulls new service entrance conductors (upgrading from 2 AWG or smaller to 2/0 copper or 4/0 aluminum), installs a new service panel with adequate circuit positions for current and future needs, and completes the upgraded grounding system. Many contractors schedule this work for mild weather when loss of HVAC isn’t critical and coordinate with homeowners to protect refrigerated food and make arrangements for any medical equipment requiring continuous power.

Service Upgrade Cost Breakdown

Material Costs:

200A meter base: $150-300
200A service panel (40-space): $200-400
Service entrance conductors (100 ft): $150-500 (aluminum to copper range)
Grounding system components: $100-200
Conduit and fittings: $100-250
Miscellaneous hardware: $50-100

Labor Costs:

Electrical contractor: $1,500-3,500 (varies by region and complexity)
Utility company service upgrade fee: $0-500 (varies by utility)
Permit fees: $150-500
Inspection fees: Usually included in permit

The upgrade also provides an opportunity to improve the overall electrical system with modern safety features. Current code requirements mandate arc fault circuit interrupter (AFCI) protection for most residential circuits and ground fault circuit interrupter (GFCI) protection in bathrooms, kitchens, garages, and outdoor areas. Installing a new service panel allows the electrician to incorporate these protective devices, significantly enhancing electrical safety beyond what the old system provided. Many homeowners also use the service upgrade as an opportunity to add dedicated circuits for specific loads like electric vehicle charging, home workshops, or outdoor kitchens that the old 100 amp service couldn’t support.

Special Considerations for Different Building Types

Understanding what size wire for 200 amp service varies somewhat depending on whether the installation is for a single-family residence, multi-family dwelling, or commercial building. Single-family residential installations follow the standard specifications discussed throughout this guide, with 2/0 copper or 4/0 aluminum service entrance conductors and relatively straightforward grounding requirements. The service typically enters at a single point, feeds a single meter base and main panel, and serves the entire residence from that central distribution point. Load calculations for single-family homes follow NEC Article 220 Part III, which includes specific demand factors for various load types that recognize that not all electrical loads operate simultaneously.

Multi-family dwellings require more complex service configurations that affect conductor sizing and installation methods. Many newer multi-family buildings use individual 200 amp services for each dwelling unit, requiring multiple meter bases and service panels all fed from a common service point. The main service conductors feeding the meter bank must be sized to handle the combined demand load of all units, typically calculated using diversity factors that account for the statistical probability that not all units will peak simultaneously. A 10-unit building with individual 200 amp services might require 600-800 amp main service conductors rather than the full 2000 amps that would result from simple addition. These calculations require professional electrical engineering to ensure adequate capacity while avoiding significant overcapacity costs.

Building Type Service Characteristics

Single-Family Residential:

Standard 200A service: 2/0 Cu or 4/0 Al
Single meter and panel
Simplified grounding system
Load calculation: NEC 220.82 (standard method) or 220.83 (optional method)

Multi-Family Dwelling:

Individual services: 2/0 Cu or 4/0 Al per unit
Main service: Sized by engineering calculations with diversity factors
Multiple meter banks
Complex grounding and bonding requirements
Load calculation: NEC 220.84 with demand factors

Commercial Building:

Service size: Engineering calculations based on actual loads
Often three-phase service
Larger conductor sizes common (300-500 kcmil or larger)
Extensive grounding and fault current considerations
Load calculation: NEC Article 220 Part IV

Commercial buildings present entirely different considerations for service entrance design and wire sizing for 200 amp service installations. Commercial loads often include large motors, HVAC equipment, and specialized machinery that create significant inrush currents and require three-phase power. The service entrance conductors must be sized not only for continuous amperage but also for the voltage drop impact of motor starting currents and the fault current available from the utility transformer. Commercial installations typically require detailed electrical engineering calculations, specialized equipment ratings, and coordination with the local utility for transformer sizing and protection requirements. The conductor sizes for commercial 200 amp services may actually exceed those for residential applications if the service must handle specific load characteristics or maintain stringent voltage regulation requirements.

Future-Proofing Your 200 Amp Service Installation

When determining what size wire for 200 amp service installations, considering future electrical load growth can prevent costly upgrades down the road. Electric vehicle adoption is accelerating rapidly, with level 2 home chargers typically requiring 40-50 amp dedicated circuits. Installing provisions for future EV charging during the initial service upgrade, such as a 60 amp feeder to the garage with a temporary 30 amp breaker, allows easy future expansion without major electrical work. Similarly, planning for potential additions like pool equipment, workshop machinery, or backup generator connections during the initial installation costs relatively little compared to retrofitting these capabilities later.

Oversizing conduit during 200 amp service wire installation provides flexibility for future conductor upgrades without excavation or demolition. Installing 2.5-inch conduit instead of the 2-inch minimum for aluminum 4/0 service conductors allows future upgrade to copper conductors or even to 400 amp service using larger aluminum conductors. This minimal upfront cost provides significant long-term value, especially for properties where electrical demand may increase substantially over the typical 30-40 year lifespan of the service entrance installation. Many forward-thinking electricians routinely oversize conduit by one size class specifically to accommodate future unknown needs without compromising current installation costs significantly.

Future-Proofing Strategies

Oversize conduit by one size – Minimal cost now, significant flexibility later
Install 200A panel with 40+ circuit positions – Accommodates future circuit additions
Include spare conduits – Stubbed to attic/basement for future solar or generator
Specify copper over aluminum – Easier to work with for future modifications
Install whole-house surge protection – Protects sensitive electronics, easy to add during service work
Plan for subpanel locations – Run feeders during initial construction rather than retrofitting
Document installation details – Photos and notes help future electricians understand system configuration

Energy efficiency improvements and renewable energy installations interact with 200 amp service capacity in ways that property owners should understand. Adding solar photovoltaic systems requires either a supply-side connection before the main breaker or ensuring the combined solar breaker and main breaker ratings don’t exceed 120% of the panel bus bar rating. For example, a 200 amp panel can typically accommodate a maximum 40 amp solar breaker when using the 120% rule (200A × 1.2 = 240A limit, with 200A main + 40A solar = 240A total). Larger solar systems may require service upgrades to 400 amps or specialty equipment to avoid exceeding this limitation. Battery backup systems and whole-house generators have similar integration considerations that should be planned during the initial service installation when possible.

Cost Analysis and Budget Planning

Accurately budgeting for what size wire for 200 amp service installation requires understanding both material and labor costs, which vary significantly by region and installation complexity. Basic materials for a straightforward 200 amp service upgrade including meter base, panel, conductors, conduit, and grounding components typically cost $800-1,500 for aluminum conductor installations or $1,200-2,200 for copper. Labor costs often exceed material costs, with licensed electrical contractors charging $75-150 per hour in most markets and typical installations requiring 12-20 hours of work depending on the specific site conditions and distance from the utility connection point to the service panel location.

Regional variations significantly impact total project costs, with urban areas and high-cost-of-living regions commanding premium rates for both materials and labor. A 200 amp service upgrade might cost $2,500-3,500 in rural areas with straightforward installations but exceed $6,000-8,000 in major metropolitan areas or for installations requiring extensive trenching, utility coordination, or complex panel relocations. The utility company may also assess fees for their portion of the service upgrade, including new transformer installation or service drop modifications, which can range from zero in some jurisdictions to $500-2,000 in others. These utility fees are separate from the electrical contractor’s scope but must be included in total project budgeting to avoid unexpected costs.

Budget Planning Considerations

Base Installation Costs:

Materials: $800-2,200
Labor (15 hours average): $1,125-2,250
Permits and inspections: $150-500
Utility fees: $0-2,000
Total basic installation: $2,075-6,950

Additional Costs (if required):

Trenching for underground service: $15-30 per linear foot
Service mast replacement: $300-800
Panel relocation: $500-1,500
Asbestos/lead paint remediation: $500-5,000
Tree trimming for overhead clearance: $200-1,000
Grounding system upgrades: $200-600

Financing options can make large electrical service upgrades more accessible to homeowners. Many electrical contractors offer payment plans or work with financing companies specializing in home improvement loans with terms ranging from 12-60 months. Some utility companies provide rebates or low-interest loans for electrical service upgrades that improve energy efficiency or support electric vehicle adoption. The federal government and many states also offer tax credits for certain electrical improvements including EV charger installation and renewable energy system integration, which may offset a portion of the service upgrade costs when these elements are included in the project scope. Investigating these financing and incentive opportunities before committing to a contractor can significantly reduce the net cost of 200 amp service wire installation projects.

Frequently Asked Questions About What Size Wire for 200 Amp Service

What size wire do I need for 200 amp service underground?

For underground 200 amp service installations, you need 2/0 AWG copper or 4/0 AWG aluminum conductors with USE-2 or RHW-2 rated insulation specifically approved for direct burial or underground conduit installation. The conductors must be installed in Schedule 40 PVC conduit at minimum depths specified by local code, typically 24 inches for residential installations. If you choose direct burial without conduit, the conductors must be rated for direct earth contact and installed at greater depths, usually 30 inches minimum. Underground installations should include a warning tape or marking system 12 inches above the buried conductors to alert future excavators to the presence of electrical lines.

Can I use 3/0 wire for 200 amp service?

While 3/0 copper wire has an ampacity rating that exceeds 200 amps (rated for 225 amps at 75°C), using 3/0 instead of the standard 2/0 for 200 amp service is actually oversizing the installation. This creates no code violation and provides extra capacity margin, but it increases material costs unnecessarily for most applications. However, 3/0 copper wire may be appropriate when voltage drop calculations indicate that 2/0 would result in excessive voltage drop on longer service runs, typically over 150 feet. The decision to upsize from 2/0 to 3/0 should be based on specific voltage drop calculations rather than arbitrary oversizing. For aluminum installations, 4/0 remains the standard size, with 250 kcmil being the next larger size used only when calculations demonstrate the need.

What size ground wire for 200 amp service is required?

The ground wire sizing for 200 amp service depends on whether you’re referring to the grounding electrode conductor or the equipment grounding conductor. The grounding electrode conductor, which connects the service panel to the grounding electrode system (typically ground rods or water pipe), must be 4 AWG copper minimum when connected to ground rods or 4 AWG copper for concrete-encased electrodes. The equipment grounding conductor, which runs with the service entrance conductors, must be 6 AWG copper or 4 AWG aluminum minimum per NEC Table 250.122. Many electricians install larger grounding conductors than the minimum to provide additional safety margin and simplify potential future service upgrades that might require larger grounding conductors.

How far can you run 200 amp service wire?

The maximum distance you can run 200 amp service wire depends primarily on voltage drop limitations rather than ampacity. For residential 240-volt service, the NEC recommends limiting voltage drop to 3% maximum, which allows approximately 100-120 feet of run using standard 2/0 copper or 4/0 aluminum conductors at full 200 amp load. However, since most residential services rarely draw the full 200 amps continuously, longer runs may be acceptable if actual load calculations show lower amperage requirements. For runs exceeding 150 feet, voltage drop calculations become essential, and conductor upsizing to 3/0 copper or 250 kcmil aluminum may be necessary to maintain adequate voltage at the panel. Consulting with a licensed electrician for proper voltage drop calculations is strongly recommended for any service run exceeding 100 feet.

Do I need copper or aluminum wire for 200 amp service?

Both copper and aluminum conductors are code-compliant for 200 amp service installations, with the choice primarily driven by cost considerations and installation preferences. Copper 2/0 AWG provides equivalent ampacity to aluminum 4/0 AWG but costs 50-70% more for the conductor material. Copper offers easier installation due to smaller physical size, superior corrosion resistance, and simpler termination requirements without anti-oxidant compound. Aluminum provides significant material cost savings and lighter weight for easier handling but requires larger conduit, special aluminum-rated terminals, anti-oxidant paste at all connections, and careful attention to proper torque specifications. For budget-conscious installations where the electrical contractor has experience with aluminum wire, aluminum represents a cost-effective choice. For installations prioritizing ease of future modifications and long-term reliability, copper is often preferred despite higher initial costs.

What size breaker do I need for 200 amp service?

The main breaker for 200 amp service must be rated for exactly 200 amps to properly protect the service entrance conductors and downstream electrical system. This 200 amp main breaker serves as the service disconnect and overcurrent protection device, preventing current draw from exceeding the 200 amp capacity of the service entrance conductors. The breaker must also have an adequate interrupting capacity (AIC rating) to safely interrupt the maximum available fault current at your location, which varies based on utility transformer sizing and distance from the source. Most residential installations use breakers with 10,000 AIC (10kAIC) or 22,000 AIC ratings, though some high-fault-current areas may require 65kAIC or higher. The utility company or local electrical inspector can provide fault current data to ensure proper breaker selection.

Can I install 200 amp service wire myself?

While technically capable individuals might physically install 200 amp service wire, most jurisdictions prohibit unlicensed persons from performing electrical service entrance work due to the significant safety implications and complexity involved. Service entrance work typically requires a licensed electrical contractor to obtain permits and typically must pass multiple inspections before the utility will provide permanent connection. Additionally, working on service entrance equipment involves exposure to utility-supplied power that cannot be de-energized by the homeowner, creating serious electrocution hazards requiring specialized training and safety procedures. Even in jurisdictions that permit homeowner electrical work, insurance companies may deny claims for damages resulting from self-installed service entrance equipment. The complexity of load calculations, conductor sizing, grounding system design, and utility coordination makes professional electrical contractor involvement strongly recommended for all 200 amp service installations.

What is the difference between service entrance wire and feeder wire?

Service entrance wire refers specifically to the conductors that run from the utility connection point (meter base) to the main service panel and must be sized for the full service rating – 2/0 copper or 4/0 aluminum for 200 amp service. These conductors operate on the line side of the main service disconnect and are subject to different code requirements than downstream circuits. Feeder wire runs from the main service panel to subpanels or other distribution equipment and is sized based on the calculated load of the circuits it supplies rather than the full service rating. A feeder from a 200 amp main panel to a garage subpanel might only need 6 AWG wire if calculations show the garage load is 60 amps or less. Service entrance conductors have no overcurrent protection at their supply end and rely on the utility’s protection, while feeder conductors must be protected by an appropriately sized breaker at their supply end.

How do I calculate voltage drop for 200 amp service wire?

Calculating voltage drop for 200 amp service wire requires knowing the total circuit length (run distance × 2 for both conductors), conductor resistance, expected load amperage, and supply voltage. The basic formula is: Voltage Drop = 2 × Length × Resistance × Current ÷ 1000, where length is in feet, resistance is in ohms per 1000 feet (obtained from wire tables: 2/0 copper = 0.0779 Ω/1000ft), and current is in amperes. For example, a 100-foot run of 2/0 copper carrying 150 amps: VD = 2 × 100 × 0.0779 × 150 ÷ 1000 = 2.34 volts. Percentage voltage drop = 2.34V ÷ 240V × 100 = 0.97%, which is well within the 3% recommendation. Online voltage drop calculators simplify this process and account for temperature coefficients and other factors affecting conductor resistance. Professional electricians typically use these calculators or reference tables to ensure installations meet voltage drop requirements.

What happens if I use undersized wire for 200 amp service?

Using undersized wire for 200 amp service creates serious safety hazards including conductor overheating, insulation degradation, and potential fire hazards when the service draws current approaching its rated capacity. Undersized conductors have higher resistance than properly sized conductors, converting more electrical energy into heat that accumulates in the conductor and surrounding insulation. Over time, this excessive heat degrades insulation, increases connection resistance at terminals, and can ignite surrounding building materials. Code violations from undersized conductors will fail electrical inspections, preventing utility connection and potentially voiding homeowner’s insurance coverage. Even if an undersized installation somehow passes inspection, it creates liability exposure for the installer and property owner if electrical fires or other damages occur. The cost savings from using smaller conductors are vastly outweighed by the safety risks and legal consequences of improper installation.

Ready to size your electrical service correctly? Understanding what size wire for 200 amp service ensures your home’s electrical system operates safely and efficiently for decades. Whether you’re upgrading from 100 amp service or installing service for new construction, always consult with licensed electrical contractors who understand local code requirements and can properly size conductors for your specific installation conditions. For more information on electrical services and professional installation requirements, visit the National Electrical Contractors Association or consult your local building department.

Additional Resources:

National Electrical Code (NEC) handbook for detailed wire sizing tables
Local utility company service requirements and connection procedures
For assistance with other service needs, including hello mobile customer service, explore professional support options

Sources and Citations:

National Electrical Code (NFPA 70) – Article 310: Conductors for General Wiring
National Electrical Code – Article 230: Services
National Electrical Code – Article 250: Grounding and Bonding
International Association of Electrical Inspectors (IAEI) – Service Entrance Requirements
Underwriters Laboratories (UL) – Wire and Cable Standards