From $0.20/ft
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Solid THHN/THWN-2 WireFrom $0.20/ft -
Solid THHN/THWN-2 WireFrom $0.20/ft - Solid THHN/THWN-2 WireFrom $0.20/ft
- Solid THHN/THWN-2 WireFrom $0.20/ft
Parent SKU : BCSTR300-37
SKU : BCSTR300-37-250
"Engineered for commercial-grade grounding rings, heavy utility infrastructure, and critical lightning mitigation networks, this 300 MCM Stranded Bare Copper wire is built for extreme current capacities. Featuring soft-drawn (annealed) copper construction and a premium 37-strand configuration, it provides an exceptionally low-resistance path to earth, making it the definitive standard for industrial substations, massive grid arrays, and high-security facility grounding."
When massive electrical projects demand a step above standard AWG or 250 MCM lines, 300 MCM (kcmil) is a common choice of commercial estimators and field engineers. This massive conductor is optimized to instantly absorb, isolate, and safely dissipate severe short-circuit fault currents and major lightning surges before they reach sensitive equipment. By separating this thick copper mass into 37 individual concentric strands, the cable maintains an exceptional balance of mechanical structural strength and workable field flexibility. It lays smoothly into trenches, shapes perfectly inside heavy-duty concrete foundations, and handles rough earth backfilling with ease.
Massive Fault-Current Shielding: 99.9% pure, uninsulated copper delivers a highly conductive, low-impedance path to ground to keep industrial grids fully protected.
Premium 37-Strand Engineering: Multi-wire concentric lay maximizes physical surface area and breaking strength while ensuring the line remains pliable enough for clean routing.
Soft-Drawn (Annealed) Temper: The thermal treating process completely relaxes the copper's mechanical memory, making it highly workable for technicians wrapping ground bars or routing corners.
Inherent Direct Burial Resistance: Natively fights off the corrosive effects of subsurface moisture and harsh soil alkalinity without requiring a protective outer jacket.
ENGINEERING OVERVIEW
Conductor Size: 300 MCM (300 kcmil)
Cross-Sectional Area: 300,000 Circular Mils
Construction: 37-StrandÂ
Temper: Soft-Drawn (Annealed)
Material: Bare Copper (Uninsulated)
Overall Diameter: 0.630 inches (16.00 mm)
Approx. Weight: 926.3 lbs per 1,000 ft (0.926 lb/ft)
DC Resistance at 20ºC: 0.03526 Ohms/1,000 ft
Rated Breaking Strength: 9,160 lbs
Ampacity Rating: 590 Amps (Based on 75°C conductor temp; 25°C ambient; 2ft./sec. wind in sun)
Compliance Standards: ASTM B-1, ASTM B-2, ASTM B-3 (Soft/Annealed), ASTM B-8 (Concentric-Lay), Federal Spec QQ-W-343Â
Commercial Grounding Rings: The definitive master size for burying deep earth loops around cloud data hubs, hospital wings, and major distribution centers.
Substation Grid Meshes: Essential for tying down underground safety grounding grids and grounding high-voltage electrical utility transformers.
High-Capacity Main Services: Connecting massive 1200A, 1600A, and 2000A main service entrance panels safely to the primary building ground.
Lightning Protection Down-Conductors: Serving as the heavy, high-mass uninsulated backbone for tall communication masts, industrial plants, and utility towers.
Overhead Power Distribution: Leveraged in heavy utility work for low-impedance overhead electrical lines and robust messenger/support applications.
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Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyer’s responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes.
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| Wire Size (AWG/MCM) | 300 MCM |
| Conductor Material | Copper |
| Conductor Type | Stranded |
| Strand Count | 37 |
| Outer Diameter (OD) (in/mm) | 0.630 in. |
| Conductor Count | 1 |
| Shield | Unshielded |
| Ampacity Rating | 590 |
| Direct Burial Rating | Yes |
| Submersible | No |
| Sunlight Resistance Rating | Yes |
| Standards | ASTM B-1 Hard-drawn copper wire ASTM B-2 Medium-hard drawn copper wire ASTM B-3 Soft or annealed copper wire ASTM B-8 Concentric-lay stranded copper conductors: hard, medium-hard, or soft ASTM B-33 Tinned soft or annealed copper wire ASTM B-258 Federal Sepc QQ-W-375 |
| Miscellaneous Information | All values are nominal and subject to correction. *Ampacity based on 75ºC conductor temperature; 25ºC ambient temperature; 2ft./sec. wind in sun. |
| Primary Applications | Grounding Systems, Overhead Power Distribution, Ground Wire for Lightning Protection, Bonding Applications, Messenger and Support Wires |
| Common Uses |
|
| Weight per Foot | 0.9263 lb |
In-stock orders placed before 3pm EST typically ship within 1-2 business days. Our business days are Monday through Friday; we do not process orders on Saturday, Sunday, or major US Holidays.
You will receive an e-mail with a tracking number within 1-2 business days from the time its shipped. You will also be able to view your order status and tracking numbers in your account order history.
Expedited shipments are delivered Monday-Friday except on US Holidays. The order must be placed before 12pm CST to ship same day ( Mon-Fri Only).
You have 30 days from the day you receive the item to contact us for a return. Returns are subject to a 30% Restocking Fee.
Please contact us at help@wireamerica.com to request a return authorization. Have your order number or name the order was placed with ready and we will email you an RMA (return) number and instructions for return. Currently, we do not offer exchanges. A new order must be placed if you need a different item. If you provide the new order number at the time of your return request, the restocking fee may be lowered.
Orders on any items with a material value of $50 or less are non-returnable.
Parent SKU : BCSTR300-37
SKU : BCSTR300-37-250
Parent SKU : BCSTR300-37
SKU : BCSTR300-37-250
"Engineered for commercial-grade grounding rings, heavy utility infrastructure, and critical lightning mitigation networks, this 300 MCM Stranded Bare Copper wire is built for extreme current capacities. Featuring soft-drawn (annealed) copper construction and a premium 37-strand configuration, it provides an exceptionally low-resistance path to earth, making it the definitive standard for industrial substations, massive grid arrays, and high-security facility grounding."
When massive electrical projects demand a step above standard AWG or 250 MCM lines, 300 MCM (kcmil) is a common choice of commercial estimators and field engineers. This massive conductor is optimized to instantly absorb, isolate, and safely dissipate severe short-circuit fault currents and major lightning surges before they reach sensitive equipment. By separating this thick copper mass into 37 individual concentric strands, the cable maintains an exceptional balance of mechanical structural strength and workable field flexibility. It lays smoothly into trenches, shapes perfectly inside heavy-duty concrete foundations, and handles rough earth backfilling with ease.
Massive Fault-Current Shielding: 99.9% pure, uninsulated copper delivers a highly conductive, low-impedance path to ground to keep industrial grids fully protected.
Premium 37-Strand Engineering: Multi-wire concentric lay maximizes physical surface area and breaking strength while ensuring the line remains pliable enough for clean routing.
Soft-Drawn (Annealed) Temper: The thermal treating process completely relaxes the copper's mechanical memory, making it highly workable for technicians wrapping ground bars or routing corners.
Inherent Direct Burial Resistance: Natively fights off the corrosive effects of subsurface moisture and harsh soil alkalinity without requiring a protective outer jacket.
ENGINEERING OVERVIEW
Conductor Size: 300 MCM (300 kcmil)
Cross-Sectional Area: 300,000 Circular Mils
Construction: 37-StrandÂ
Temper: Soft-Drawn (Annealed)
Material: Bare Copper (Uninsulated)
Overall Diameter: 0.630 inches (16.00 mm)
Approx. Weight: 926.3 lbs per 1,000 ft (0.926 lb/ft)
DC Resistance at 20ºC: 0.03526 Ohms/1,000 ft
Rated Breaking Strength: 9,160 lbs
Ampacity Rating: 590 Amps (Based on 75°C conductor temp; 25°C ambient; 2ft./sec. wind in sun)
Compliance Standards: ASTM B-1, ASTM B-2, ASTM B-3 (Soft/Annealed), ASTM B-8 (Concentric-Lay), Federal Spec QQ-W-343Â
Commercial Grounding Rings: The definitive master size for burying deep earth loops around cloud data hubs, hospital wings, and major distribution centers.
Substation Grid Meshes: Essential for tying down underground safety grounding grids and grounding high-voltage electrical utility transformers.
High-Capacity Main Services: Connecting massive 1200A, 1600A, and 2000A main service entrance panels safely to the primary building ground.
Lightning Protection Down-Conductors: Serving as the heavy, high-mass uninsulated backbone for tall communication masts, industrial plants, and utility towers.
Overhead Power Distribution: Leveraged in heavy utility work for low-impedance overhead electrical lines and robust messenger/support applications.
Â
Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyer’s responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes.
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Â
| Wire Size (AWG/MCM) | 300 MCM |
| Conductor Material | Copper |
| Conductor Type | Stranded |
| Strand Count | 37 |
| Outer Diameter (OD) (in/mm) | 0.630 in. |
| Conductor Count | 1 |
| Shield | Unshielded |
| Ampacity Rating | 590 |
| Direct Burial Rating | Yes |
| Submersible | No |
| Sunlight Resistance Rating | Yes |
| Standards | ASTM B-1 Hard-drawn copper wire ASTM B-2 Medium-hard drawn copper wire ASTM B-3 Soft or annealed copper wire ASTM B-8 Concentric-lay stranded copper conductors: hard, medium-hard, or soft ASTM B-33 Tinned soft or annealed copper wire ASTM B-258 Federal Sepc QQ-W-375 |
| Miscellaneous Information | All values are nominal and subject to correction. *Ampacity based on 75ºC conductor temperature; 25ºC ambient temperature; 2ft./sec. wind in sun. |
| Primary Applications | Grounding Systems, Overhead Power Distribution, Ground Wire for Lightning Protection, Bonding Applications, Messenger and Support Wires |
| Common Uses |
|
| Weight per Foot | 0.9263 lb |
In-stock orders placed before 3pm EST typically ship within 1-2 business days. Our business days are Monday through Friday; we do not process orders on Saturday, Sunday, or major US Holidays.
You will receive an e-mail with a tracking number within 1-2 business days from the time its shipped. You will also be able to view your order status and tracking numbers in your account order history.
Expedited shipments are delivered Monday-Friday except on US Holidays. The order must be placed before 12pm CST to ship same day ( Mon-Fri Only).
You have 30 days from the day you receive the item to contact us for a return. Returns are subject to a 30% Restocking Fee.
Please contact us at help@wireamerica.com to request a return authorization. Have your order number or name the order was placed with ready and we will email you an RMA (return) number and instructions for return. Currently, we do not offer exchanges. A new order must be placed if you need a different item. If you provide the new order number at the time of your return request, the restocking fee may be lowered.
Orders on any items with a material value of $50 or less are non-returnable.
Get notified when this product is back in stock
Physical Specifications
Technical Specifications
Usage & Installation:
Packaging & Dimensions:
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300 MCM bare copper wire is a massive, high-capacity conductor used for large-scale utility, industrial, and heavy commercial grounding networks. Due to its substantial cross-sectional area, it provides a maximum-performance, low-resistance path to the earth. It is the definitive standard for engineering substation grounding grids, main external ground loops for massive industrial plants, high-voltage utility structures, and grounding utility-scale solar or wind farm collection systems.
The nominal outside diameter (OD) of a 300 MCM stranded bare copper wire is approximately 0.630 inches (16.00 mm).
Minimum Requirement: For a single 300 MCM bare copper wire installed purely for physical protection from damage, a 1-1/4 inch PVC or EMT conduit is the standard code minimum for 40% fill.
Recommended: A 2-inch conduit is strongly recommended for long runs or runs containing multiple 90-degree elbows. At well over half an inch thick and weighing nearly a pound per foot, 300 MCM copper is incredibly heavy and stiff; a 2-inch pipe dramatically reduces pulling friction.
Note: Always consult with a certified local electrician who is up to date on all local codes.
Yes. This wire is fully rated for direct burial in soil and for direct encasement in heavy structural concrete footings (Ufer grounds). High-purity electrical copper naturally develops a protective patina when exposed to underground elements, making it highly resistant to soil-based chemical corrosion and moisture degradation for decades of reliable performance.
While both solid and stranded copper have the exact same electrical capacity, stranded wire is highly preferred by installers for its flexibility. Solid copper wire in larger gauges is incredibly rigid and behaves like a stiff metal rod in the field. Stranded wire allows installation crews to easily manipulate the conductor, bend it around foundation walls, and cleanly transition it into service panels without kinking or fighting the metal.
Wire America ships directly from regional hubs across the United States to get it to your job site fast. Most orders arrive on your doorstep within 2 to 4 business days, and for critical project deadlines or emergency line repairs, we offer expedited overnight shipping options at checkout. We stock everything from small 18 AWG to massive 1250 MCM bare copper—and we’re happy to cut it exactly to the foot (on most sizes) or ship it out on full bulk spools.
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