2/0 Aluminum Wire Ampacity, NEC Sizing, And Cost Pitfalls Exposed

Start Strong With a 2025-ready Overview of 2/0 Aluminum Wire

What is 2/0 aluminum wire?

Ever wonder what makes "two-aught" or 2/0 aluminum wire the workhorse for modern electrical projects? In the American Wire Gauge (AWG) system, 2/0 (read as "two-aught") is a heavy-gauge wire—thicker than 2 AWG and designed for serious power delivery. Unlike smaller wires, 2 0 aluminum wire is engineered to handle high current loads in residential, commercial, and light industrial settings. The "aluminum" part means the conductor is made from aluminum alloy, which is lighter and more cost-effective than copper, though slightly larger in diameter for the same ampacity.

2/0 aluminum building wire is a heavy-duty conductor—about 0.364 inches in diameter—used to safely deliver high current where copper is impractical or cost-prohibitive.

Where 2/0 wire fits vs copper in 2025

When you compare 2/0 aluminum to copper, you’ll notice aluminum is typically chosen for longer runs and large feeder circuits where weight and budget matter. For example, 2 0 awg aluminum wire is common in service entrance cables, main feeders to subpanels, and direct burial installations. While copper still leads in ampacity per cross-sectional area, aluminum’s lower density and cost make it a smart choice for large-scale or cost-sensitive projects. In 2025, code-compliant aluminum alloys (like 8000 series) and improved terminations have made 2/0 aluminum a reliable alternative to copper in most building applications.

• Service entrance feeders (main panel to meter or disconnect)
• Subpanel feeders in homes and light commercial buildings
• Temporary power for construction sites
• Underground residential distribution (URD) laterals
• Large branch circuits for HVAC or EV charging

Common constructions you will encounter

Choosing the right 2/0 wire isn’t just about the conductor—it’s about the whole assembly. Here are the most common types you’ll see:

• XHHW-2: Cross-linked polyethylene insulation, rated for wet/dry locations; robust and heat-resistant.
• THHN/THWN-2: Dual-rated for dry (THHN) and wet (THWN-2) environments; versatile and widely available.
• USE-2 cable: Designed for underground service entrance and direct burial; sunlight- and moisture-resistant.
• SER: Service entrance cable with multiple conductors (often 2/0 aluminum); used for feeders.
• URD: Underground Residential Distribution cable, usually triplexed for direct burial without conduit.

Key code concepts before you size

Before you select a 2/0 aluminum cable, consider these essentials:

• Ampacity limits: The maximum current the wire can safely carry, which varies by insulation type and installation method.
• Termination temperature ratings: Most lugs and breakers are rated for 60°C or 75°C, even if the wire is rated 90°C.
• Installation environment: Wet, dry, underground, or in conduit—each impacts your insulation choice and code requirements.

By understanding what 2/0 aluminum wire is, where it excels, and the key factors in selecting the right construction, you’re ready to make informed choices for safe, code-compliant projects in 2025 and beyond. Ready to dig deeper into ampacity and sizing? Let’s move on to the next section.

Get ampacity right with clear NEC guidance

NEC ampacity for 2/0 aluminum at 60°C, 75°C, 90°C

When you’re sizing 2/0 aluminum wire, the first question is always: how many amps is 2/0 aluminum good for? The answer depends on insulation type, installation method, and—most importantly—equipment termination ratings. The National Electrical Code (NEC) Table 310.16 (formerly 310.15(B)(16)) is your starting point for finding the base ampacity of 2/0 aluminum conductors under standard conditions (no more than three current-carrying conductors, 30°C/86°F ambient temperature).

• NEC 310.16: Base ampacity for aluminum conductors by insulation and temperature rating.
• NEC 110.14(C): Termination temperature limits and rules for selecting ampacity columns.
• NEC 310.15(B)(1), (B)(2): Adjustments for ambient temperature and conductor bundling.

So, what is 2 0 aluminum wire rated for in a typical installation? Unless you have special equipment, the ampacity of 2 0 aluminum wire is usually limited to 150 amps (75°C column), even if the wire itself can technically carry up to 175 amps at 90°C.

Termination temperature limits that actually govern

It sounds counterintuitive, but the ampacity of 2 0 aluminum wire is not just about the wire—it’s about where you connect it. NEC 110.14(C) requires you to size according to the lowest-rated termination on the circuit. Most residential and commercial distribution equipment (like breakers, lugs, and panelboards) are rated for 75°C. Even if you use a 90°C-rated insulation (such as XHHW-2 or THHN/THWN-2), you must use the 75°C ampacity column for sizing unless both ends are marked and listed for 90°C terminations—which is almost never the case below 600V.

For example, if you’re installing a 2/0 aluminum feeder to a panel with 75°C lugs, your maximum allowed ampacity is 150A. If one end of the run lands on a device with a 60°C termination (rare for 2/0, but possible with some older equipment), you must use the 60°C column—dropping your ampacity to 135A.

Always size to the equipment’s lowest temperature rating unless a code exception applies.

For more on this, see the detailed discussion on termination ratings and their impact on conductor sizing at IAEI Magazine.

When and how to apply derating factors

Imagine you’re running several 2/0 aluminum wires in a conduit through a hot attic, or you’re bundling more than three current-carrying conductors in a raceway. Now, you must apply derating factors as required by NEC 310.15(B)(1) (ambient temperature) and 310.15(C)(1) (number of conductors).

• Ambient temperature above 30°C (86°F): Apply a correction factor from NEC Table 310.15(B)(1). For instance, at 40°C (104°F), the correction factor for 75°C insulation is 0.88. So, 150A × 0.88 = 132A.
• More than three current-carrying conductors: Apply an adjustment factor from NEC Table 310.15(C)(1). For 4–6 conductors, the factor is 0.80. If you have both high ambient and more than three wires, multiply both factors: 150A × 0.88 × 0.80 = 105.6A.

Derating can quickly reduce the usable ampacity of 2/0 aluminum wire amps, so it’s critical to check these conditions for every installation. The NEC requires you to use the lowest resulting ampacity after all adjustments, and to ensure your overcurrent protection does not exceed that value (reference).

To sum up, the 2 0 awg aluminum wire ampacity you can actually use is often less than the theoretical maximum—and what is 2 0 aluminum wire rated for on paper may be different from what you’re allowed to use in practice. Always check your terminations and conditions of use before finalizing your wire size. Up next: step-by-step sizing examples that show how these rules play out on real projects.

Worked sizing examples you can reuse

Ever get stuck wondering if your 2/0 aluminum wire choice really meets code—or if you’ll run into an inspector’s red pen? Let’s walk through three real-world scenarios that demystify the process. By following these step-by-step examples, you’ll see exactly how to size a 2 0 feeder, apply derating for tough environments, and make the right call on overcurrent protection. Whether you’re planning a 150 amp ser cable run, a complex subpanel feed, or a 2 0 aluminum service wire upgrade, these samples model the logic pros use for safe, code-compliant installs.

Example 1: Sizing a 150A feeder with 75°C lugs

1. Base ampacity lookup: From NEC Table 310.16, 2/0 aluminum (XHHW-2, THHN/THWN-2, or USE-2) has a base ampacity of 150A at 75°C—the standard for most panel lugs.
2. Termination limit check: Equipment lugs are rated 75°C, so you must use the 75°C column (even if the wire is rated 90°C).
3. Continuous load rule: For feeders with continuous load, size conductors so their ampacity is not less than the noncontinuous load plus 125% of the continuous load, per NEC 215.2(A)(1) (reference).
4. Adjustment/correction: No derating needed if ambient temperature is 30°C or below and no more than three current-carrying conductors.
5. Final selection: 2/0 aluminum wire is the minimum size for a 150A feeder with 75°C lugs. Use a 150A breaker for overcurrent protection.

Derating from the 90°C column is allowed, but final ampacity must not exceed the 75°C column when lugs are 75°C (NEC 110.14(C)).

Example 2: Outdoor raceway at 40°C with 6 current-carrying conductors

1. Base ampacity lookup: 2/0 aluminum wire, 75°C column = 150A.
2. Termination limit check: Still limited to 75°C column due to equipment lugs.
3. Ambient correction: At 40°C, apply a correction factor of 0.88 (per NEC Table 310.15(B)(1)).
   150A × 0.88 = 132A.
4. Conductor count adjustment: Six current-carrying conductors require a 0.80 factor (NEC Table 310.15(C)(1)).
   132A × 0.80 = 105.6A.
5. Final selection: 2/0 aluminum is now only good for 105.6A. If you need to carry more, upsize to 3/0 or 4/0 aluminum, or reduce the number of conductors per raceway.

Derating for both high ambient and multiple conductors can quickly reduce usable ampacity—always check these factors for your 2/0 service wire and 2 0 triplex runs.

Example 3: Service entrance with continuous HVAC load

1. Base ampacity lookup: For a 150A calculated load (e.g., whole-home HVAC plus general lighting), NEC Table 310.12(A) calls for 2/0 aluminum for a 150 amp service entrance cable (source).
2. Continuous load rule: If the HVAC is continuous (runs 3+ hours), size for 125% of that load plus any noncontinuous loads, as required by NEC 230.42 and 215.2(A)(1).
3. Termination limit check: Most service equipment lugs are 75°C, so use the 75°C column (150A).
4. Adjustment/correction: If installed outdoors in sunlight or conduit, check for any additional derating (rare for open-air 2/0 aluminum service wire, but always verify site conditions).
5. Final selection and OCPD pairing: 2/0 aluminum service wire is adequate for a 150A main panel; pair with a 150A main breaker. For larger loads, use 4/0 aluminum for 200A service.

For residential service entrance, 2/0 aluminum is the standard for 150A panels; always confirm calculated load and equipment ratings for your 2/0 service wire or 2 0 triplex installation.

These examples show that while code tables provide a starting point, actual wire sizing for 2 0 ser, 2/0 service wire, and 2 0 feeder runs must account for every detail—termination ratings, continuous loads, ambient conditions, and conductor count. Always double-check these variables before finalizing your cable selection or ordering a 150 amp service entrance cable. In the next section, we’ll dive deeper into the metallurgy and material science that make modern aluminum wire safe and reliable for these demanding applications.

Material science essentials for better decisions

Why 8000 series aluminum changed the game

When you hear about modern 2/0 aluminum wire, you’re really talking about conductors made from 8000-series aluminum alloys. But why does this matter for your next project? In the past, older aluminum alloys (like AA-1350) caused headaches—loose connections, excessive creep, and even fire hazards. Today’s 8000 series, engineered with small amounts of iron, silicon, copper, and manganese, delivers a blend of strength, flexibility, and conductivity that’s purpose-built for building wire. These improvements mean your 2/0 cable diameter stays manageable, your terminations stay tight, and your installations last longer—even in tough environments. In fact, the 8000 series alloys are now the only solid or stranded aluminum conductors permitted for building wire by the NEC, meeting ASTM B800 and UL standards.

• High strength-to-weight ratio
• Improved flexibility and formability
• Excellent conductivity for power distribution
• Corrosion resistance for long-term reliability
• Engineered to reduce creep (cold flow) at connections

Conductivity and size tradeoffs vs copper

Wondering why the diameter of 2/0 wire is larger for aluminum than copper? It comes down to conductivity. Aluminum offers about 61% the conductivity of copper, so to carry the same current, you need a larger cross-sectional area. For example, a 2/0 awg aluminum wire typically has a diameter of about 0.364 inches, while the copper equivalent is smaller. This means a 2/0 aluminum wire diameter is bigger, but the wire is still much lighter—roughly half the weight of copper for the same ampacity (see comparison).

So, when selecting a 2/0 aluminum wire, you gain significant weight and cost savings. And if you’re looking for the metric equivalent, 2 0 awg a mm2 is approximately 67.4 mm²—a key spec for international projects or cross-referencing global standards.

Thermal expansion, creep, and long-term joints

Imagine your wire connections loosening over time—sounds risky, right? This is where the material science of 8000-series alloys really matters. Aluminum expands more than copper with temperature changes and can slowly deform (creep) under sustained pressure. The 8000 series dramatically reduces creep compared to legacy aluminum, making terminations more stable over decades. Still, it’s important to use the right connectors and torque specs, as recommended by UL and manufacturer guidelines. Proper installation, periodic inspection, and re-torquing can help keep your 2/0 aluminum wire joints safe and reliable for the life of the system.

• Resistivity: Higher than copper, requiring a larger diameter for the same ampacity
• Tensile strength: Sufficient for building wire, with added alloying elements for durability
• Creep resistance: Significantly improved in 8000 series; critical for stable terminations
• Thermal expansion: Higher than copper, so proper installation and connector selection are essential

Regular inspection and re-torquing of aluminum wire terminations are key practices for long-term safety and reliability—don’t skip this step in your maintenance plan.

By understanding the material advances behind 2/0 aluminum wire, you’ll make better choices for your next installation—balancing performance, safety, and cost. Up next, we’ll cover code-compliant terminations and the best practices that keep your connections trouble-free for years to come.

Best practices for 2/0 aluminum wire connections

When you’re working with 2/0 awg aluminum wire, the most common point of failure isn’t the cable itself—it’s the termination. Sounds complex? It doesn’t have to be. By following proven code-compliant methods, you can ensure your 2/0 electrical cable connections are safe, reliable, and inspection-ready for years to come. Let’s break down the essential steps and choices, from lug selection to torque, antioxidant use, and inspection tips.

Selecting the right AL/CU lugs for 2/0 aluminum wire

Imagine landing your 2/0 xhhw aluminum wire in a panelboard or disconnect. The connector you choose is critical. Most modern 2/0 aluminum wire terminations use dual-rated AL7CU or AL9CU lugs, which are approved for both aluminum and copper conductors. These lugs are typically made from tin-plated aluminum alloys and are listed to UL 486A-486B standards for safety and performance (reference).

• Compression lugs: Require a crimping tool and are often pre-filled with antioxidant compound. Provide a permanent, tamper-resistant connection.
• Mechanical (set-screw) lugs: Most common for field terminations. Easy to install, require proper torque, and are often dual-rated for AL/CU.

Pros and Cons: Compression vs. Mechanical Lugs

• Compression lugs
  • Pros: Secure, low-resistance connection; ideal for high-vibration or critical circuits.
  • Cons: Require special tools and dies; less flexible for field changes.
• Mechanical lugs
  • Pros: Fast installation, easy to inspect and retorque; flexible for most panel and device terminations.
  • Cons: Risk of under- or over-tightening if torque specs are ignored.

*Always refer to the equipment label or manufacturer’s data sheet for exact torque values and approved lug types. If the label is missing, consult UL 486A-486B or the product documentation (example torque chart).

Torque specs, anti-oxidant, and workmanship

Ever wonder why some connections fail even with the right lug? It’s usually a workmanship issue—especially improper torque or missing anti-oxidant compound. NEC 110.14 and UL 486A-486B require that you torque connections to the manufacturer’s specification, not just “hand tight.” Over-tightening can be just as risky as under-tightening, potentially damaging both the lug and the conductor.

• Use a calibrated torque wrench or screwdriver for every connection.
• For 2/0 awg aluminum wire, a typical mechanical lug torque is 180 in-lbs (always confirm with the label).
• Wire brush the stripped conductor to remove oxide and debris before termination—unless using a pre-filled compression lug.
• Apply an approved antioxidant compound to the conductor if recommended by the lug or cable manufacturer. This helps prevent oxidation and ensures a low-resistance connection.
• Never “ring cut” the insulation; use proper stripping tools to avoid nicking the conductor strands.

Torque to the label, not memory—document the reading.

Inspection tips that pass the first time

Imagine the frustration of a failed inspection because of a missed detail. To avoid setbacks, here’s what inspectors look for on 2/0 electrical cable terminations:

• Lug and conductor are both listed and sized for aluminum (look for AL7CU/AL9CU marking).
• Visible evidence of proper torque (torque witness mark, log, or tool setting).
• Clean conductor ends, properly stripped and brushed, with antioxidant applied if required.
• Manufacturer’s documentation or label confirming torque specs and compatibility.
• No signs of over-tightening, conductor damage, or insulation nicks.

Remember, the diameter of 2/0 wire with insulation (such as 2/0 xhhw aluminum wire) will vary by insulation type—so always verify that your lugs and raceway have enough room for the full cable diameter, not just the bare conductor.

By mastering these termination best practices, you’ll ensure your 2/0 aluminum wire installations are safe, code-compliant, and trouble-free for years to come. Next, we’ll explore how to choose the right cable assembly for different service entrance and underground applications.

SER, SEU, and URD options made clear

When to choose SER vs SEU vs URD

Ever stared at a wall of cables and wondered, “Which 2/0 aluminum assembly is right for my project?” The answer depends on where you’re running the wire and what the installation demands. Let’s break down the three most common choices for 2/0 aluminum service and feeder cables:

1. Indoor Feeder (Above Ground): Choose SER cable for subpanel feeders and branch circuits inside buildings or on exterior walls above ground. 2/0 ser cable includes two or three insulated phase conductors, a neutral, and a bare ground—making it ideal for feeding panels after the main disconnect.
2. Main Service Entrance (Panel to Meter): Use SEU cable for the service drop from the meter to the main service panel. SEU has phase conductors and a concentric neutral but no separate ground, so it’s only suitable up to the service disconnect—never as a feeder to a subpanel.
3. Underground Lateral (Direct Burial): For runs from a transformer or pedestal to a building, URD (Underground Residential Distribution) cable—specifically 2/0-2/0-2/0 aluminum wire triplex—is the go-to. It’s engineered for underground installation and can be direct buried without conduit.

Grounding, bonding, and neutral isolation rules

Sounds complex? Here’s the simple version: SER cable has both a neutral and a ground, so it’s perfect for subpanel feeders where neutral and ground must be separated (per NEC 250). SEU only has a neutral, so it can’t be used to feed subpanels—just up to the main disconnect, where neutral and ground are bonded. For underground runs, 2/0-2/0-2/0 aluminum wire triplex URD cables typically include two phase conductors and a neutral, but not a ground; you must provide a separate equipment grounding conductor if required by code.

• At the main service, neutral and ground are bonded together.
• At subpanels, neutral and ground must be isolated.
• For direct burial, always confirm that your installation meets NEC 250 for equipment grounding and NEC 230 for service conductors.

Direct burial vs conduit best practices

Imagine you’re running a lateral from a utility transformer to a home—should you use conduit or direct burial? Here’s how to decide:

1. If you need the fastest, most economical installation and local code allows, use 2/0 urd aluminum wire or USE-2 cable for direct burial. These are rated for burial without conduit and have robust moisture/sunlight resistant insulation.
2. If extra mechanical protection is needed (driveways, rocky soil, or future digging risk), run your 2/0 2/0 2/0 service entrance cable in schedule 40 or 80 PVC conduit, even if the cable itself is rated for direct burial.
3. For indoor or above-ground runs, always use SER or SEU—never URD or USE-2, as they’re not rated for indoor use.

For example, a 2/0 aluminum wire direct burial installation using 2/0-2/0-2/0 URD can handle up to 245A per manufacturer data, but always check local code and utility requirements.

Service entrance conductors (like 2/0-2/0-2/0 aluminum wire) follow NEC 230 special rules, which may differ from standard feeder requirements—always verify with your local inspector.

By understanding the differences between 2/0 ser cable, SEU, and 2/0 urd aluminum wire, you can make confident, code-compliant choices for every environment—from subpanels to direct burial wire. Next, we’ll cover procurement, cost, and logistics tips to help you order and handle these cables with confidence.

Procurement, pricing, and logistics that save time

Ordering 2/0 aluminum by the foot or full reels

When you’re ready to buy 2/0 aluminum wire, you’ll notice suppliers offer it by the foot, in standard put-ups, or as full reels. Sounds complex? Not really—here’s how it works in practice:

• By the foot: Ideal for small jobs or repairs. You can order exactly what you need, minimizing waste. Many retailers and distributors offer cut-to-length service on products like 2/0 XHHW-2, 2/0 ser aluminum wire, and 2/0 triplex aluminum wire. Be aware that small-quantity orders might carry a higher per-foot price and sometimes a minimum cut fee.
• Full reels or spools: Best for large projects or contractors. Standard reel sizes vary (often 500 ft, 1,000 ft, or custom), and buying in bulk usually means a lower price per foot. Some suppliers offer custom packaging—such as parallel reels, compartmental reels, or layered cuts—to match your installation needs.

Lead times for common constructions like 2/0 underground wire or 2/0 ser aluminum wire are typically short for stock items, but special colors, long lengths, or parallel pulls may require extra days for processing. Always confirm availability and delivery schedules before finalizing your order.

Spec sheet checklist to avoid change orders

Imagine receiving your cable only to find it’s the wrong type or missing a required certification. To avoid costly delays, always request a detailed specification sheet and supporting documents. Here’s a checklist you can use for every 2/0 aluminum wire order:

• UL listing and file number (confirms electrical code compliance)
• Insulation type (e.g., XHHW-2, USE-2, THHN/THWN-2)
• Stranding and alloy (typically 8000 series, per ASTM B800/B801)
• Color(s) required (especially for multi-phase or code-specific projects)
• Voltage rating (typically 600 V for building wire)
• Country of origin (COO) certificate
• Test reports and reel tags (to verify length and batch)

Requesting these documents up front helps prevent change orders and ensures your 2/0 triplex aluminum wire or 2/0 underground wire meets both project specs and inspection requirements.

Cost and weight tradeoffs vs copper

Wondering why 2 0 wire aluminum is so popular for large feeders? The answer is simple: cost and weight. Aluminum conductors are much lighter and less expensive than copper, especially for long runs or high-ampacity circuits. But it’s not just about price—handling and shipping logistics matter too.

*Prices are approximate and fluctuate daily with commodity markets. For reference, see retail listings for 4 0 4 0 2 0 aluminum wire home depot, 4/0 aluminum wire 200 amp service home depot, or supplier price sheets for 3/0 aluminum wire price comparisons.

Aluminum’s lighter weight means easier handling, lower shipping costs, and less strain during installation. For example, a 1,000-foot reel of 2/0 aluminum weighs about 160 lbs, while copper would be double that—saving you time and labor, especially on large jobs.

• Order extra length to account for routing and waste—cut lengths may not be returnable.
• Verify that your cable pull equipment can handle the total reel weight.
• Confirm that your installation environment matches the cable’s rating (direct burial, wet, sunlight-resistant, etc).

Retailers and distributors may have minimum cut lengths and special order policies. Pricing is commodity-linked—always check for up-to-date quotes before ordering.

By following these procurement and logistics best practices, you’ll avoid costly surprises and keep your 2/0 aluminum wire project on track. Next, we’ll wrap up with field-proven case studies and job aids that help you turn this knowledge into action.

Field-proven case studies and ready-to-use tools for 2/0 aluminum wire

Ever wonder what separates a smooth inspection from a frustrating rework on your 2/0 aluminum wire job? It often comes down to real-world details—like following the right checklist, documenting your torque, and understanding how code rules play out on site. Let’s look at two anonymized, field-tested case studies and share practical tools you can use on your next project.

Case study A: 2/0 SER feeder done right

Imagine you’re tasked with upgrading a residential subpanel using 2/0 ser cable. The feeder runs from the main service entrance panel to a detached garage. Here’s how the pro handled it:

• Wire selection: Chose 2/0 SER aluminum, confirming it met ampacity for a 150A feeder per NEC 310.16 and 75°C termination limits.
• Terminations: Used dual-rated AL7CU lugs, applied approved antioxidant, and wire-brushed each conductor before landing.
• Torque documentation: Used a calibrated torque wrench, recorded the value in a torque log, and marked each lug for inspector verification.
• Inspection outcome: Passed on the first visit—inspector cited clear torque records and code-compliant lug selection as key success factors.

This approach not only ensured the 2/0 ser installation was safe and code-compliant, but also saved time by anticipating exactly what the inspector would check.

Case study B: 2/0 URD lateral and inspection

Now, picture a utility lateral supplying power to a new outbuilding using 2/0 urd cable. The contractor’s steps:

• Product choice: Selected 2 0 2 0 2 0 urd aluminum wire, confirming it was triple-rated (USE-2, RHH, RHW-2) for direct burial and outdoor use.
• Ambient and burial checks: Applied ambient temperature correction for a 40°C summer install, and confirmed trench met minimum burial depth.
• Grounding: Installed a separate ground wire as required, since triplex URD does not include an equipment ground.
• Inspection outcome: Inspector approved on first pass, noting proper documentation of cable ratings and burial depth. The 2 0 service wire selection was validated by both code and utility requirements.

By verifying that the 2 0 2 0 2 0 urd cable was properly rated and applying the right adjustments, the job avoided costly callbacks and ensured long-term reliability.

Downloadable checklists and templates

Want to make your next 2/0 aluminum wire installation as smooth as these cases? Use these job aids to avoid common pitfalls:

1. Step-by-step wire sizing template:
   • Determine load (continuous/noncontinuous)
   • Find base ampacity (NEC Table 310.16)
   • Apply derating for ambient temp and conductor count
   • Check termination temperature limits
   • Select final wire size and overcurrent device
   • Document all calculations for inspection

Key takeaway: Always size your service entrance cable 2 0 or 2 0 2 0 2 0 urd to the lowest-rated termination, and keep a torque log for every connection—these are the details that pass inspection and prevent callbacks.

Armed with these field-proven strategies, checklists, and templates, you’re ready to turn code knowledge into real-world project success—saving time, passing inspections, and building safer electrical systems every time.

Frequently Asked Questions about 2/0 Aluminum Wire

1. What is 2/0 aluminum wire used for?

2/0 aluminum wire is commonly used for high-current electrical applications such as service entrance feeders, subpanel feeders, underground residential distribution (URD) laterals, and large branch circuits. It is chosen for its balance of ampacity, lighter weight, and cost savings compared to copper, making it ideal for residential, commercial, and light industrial projects.

2. How many amps is 2/0 aluminum wire rated for?

The ampacity of 2/0 aluminum wire depends on insulation type, installation, and termination temperature ratings. Typically, it is rated for 150 amps when using 75°C-rated terminations, which is standard for most electrical panels and equipment. Under specific conditions and with 90°C insulation, it can be rated up to 175 amps, but the lowest-rated termination always governs the final ampacity.

3. Can 2/0 aluminum wire be used for direct burial?

Yes, certain constructions of 2/0 aluminum wire, such as USE-2 cable and 2/0-2/0-2/0 URD triplex, are designed for direct burial. These cables have insulation and jackets that are resistant to moisture and sunlight, making them suitable for underground installations without conduit, as long as local codes and utility requirements are met.

4. What are the key differences between SER, SEU, and URD cables?

SER cable is used for above-ground feeders and includes both a neutral and ground, making it suitable for subpanels. SEU cable is intended for main service entrance from the meter to the main panel and lacks a separate ground. URD cable, such as 2/0-2/0-2/0 aluminum wire, is used for underground laterals and is rated for direct burial, typically without an equipment ground, so a separate ground may be required.

5. Why choose 2/0 aluminum wire over copper for large feeders?

2/0 aluminum wire offers significant cost and weight savings compared to copper, especially for long runs or high-ampacity circuits. While aluminum conductors are larger in diameter for the same ampacity, they are much lighter and easier to handle. Modern 8000-series aluminum alloys also provide improved reliability and safety for building wire applications.