Description

Technical Parameters

Certification

Copper THHN/THWN-2 Wire

PRODUCT REAL SHOT

300 Kcmil UL 83 Copper THHN/THWN-2 Wire Thermoplastic Insulated Building Wire

300 kcmil UL 83 Copper THHN/THWN-2 Wire Thermoplastic Insulated Building Wire

This 300 kcmil UL 83 Copper THHN/THWN-2 Wire is a heavy-duty thermoplastic insulated building wire manufactured in strict compliance with UL 83 standards, engineered for high-current power distribution in commercial and industrial construction. It features a high-purity annealed copper conductor with a dual-layer thermoplastic construction - PVC insulation beneath a tough nylon jacket - delivering both THHN dry-location and THWN-2 wet-location temperature ratings. It is the industry-standard specification for main feeders and high-load circuits in commercial buildings and industrial plants.

PRODUCT SPECIFICATIONS

high conductivity THHN copper wire

Conductor Size	Conductor Stranding	Insulation Thickness	Jacket Thickness	Nominal O.D.	Approx Net Weight	Allowable Ampacities(1) @30℃ Ambient
AWG or kcmil	Number of Strands	mils	mils	Inch	lbs/1000ft.	75℃	90℃
14	1	15	4	0.101	17	20	25
12	1	15	4	0.119	25	25	30
10	1	20	4	0.150	39	35	40
14	19	15	4	0.113	16	20	25
12	19	15	4	0.133	25	25	30
10	19	20	4	0.164	39	35	40
8	19	30	5	0.218	63	50	55
6	19	30	5	0.252	96	65	75
4	19	40	6	0.325	153	85	95
3	19	40	6	0.353	193	100	115
2	19	40	6	0.381	236	115	130
1	19	50	7	0.437	300	130	145
1/0	19	50	7	0.480	373	150	170
2/0	19	50	7	0.522	464	170	195
3/0	19	50	7	0.572	577	200	225
4/0	19	50	7	0.629	719	230	260
250	37	60	8	0.703	857	255	290
300	37	60	8	0.758	1019	285	320
350	37	60	8	0.808	1181	310	350
400	37	60	8	0.851	1342	335	380
500	37	60	8	0.937	1665	380	430
600	61	70	9	1.036	2002	420	475
750	61	70	9	1.134	2465	475	535
1000	61	70	9	1.273	3296	545	615

CERTIFICATIONS

high conductivity Copper THHN/THWN-2 Wire

PACKAGING

Plastic Reel

colored PVC insulation Copper THHN/THWN-2 Wire

Small Wooden Reel

Large Wooden Reel

APPLICATION

clear nylon jacket Copper THHN/THWN-2 Wire

Cable Tray Raceway Systems

Underground Conduit Installation

bare copper conductor Copper THHN/THWN-2 Wire

Branch Circuit Wiring

CASE

Mayo Clinic Hospital, Saint Marys Campus

stranded conductor Copper THHN/THWN-2 Wire

30 Hudson Yards

Stanford University California USA

WHY CHOOSE US

30Years of experience
in one-stop service

Dongguan Greater Wire & Cable Co., Ltd. is a professional engineering-grade cable manufacturer in China, supplying certified electrical cable solutions for building, industrial, mining, energy, and infrastructure projects worldwide.

With a 30,000 m² factory, 30 production lines, experienced engineers, and a strict quality control team, we provide reliable, traceable, and compliant cable products for international engineering applications. Our products are supported by certifications including SAA, UL, cUL, VDE, TÜV, CE, CB, IEC, BPS, and ISO.

We are committed to safety, quality, transparency, and long-term partnership. From raw material inspection to finished product testing, every batch is carefully controlled to ensure stable performance and dependable project use.

Greater Cable - Certified Quality. Reliable Supply. Engineering Value.

15K

Finished Projects

150+

professional staff

15K

happy clients

92+

awards & certifacates

PLANT EQUIPMENT

soft drawn copper Copper THHN/THWN-2 Wire

single conductor Copper THHN/THWN-2 Wire

GLOBAL CERTIFICATIONS

dry location rated THHN copper wire

CUSTOMER PHOTOS

Copper THWN-2 Wire manufacturer

INTERNATIONL TRANSPORTATION

Sea Freight

We offer reliable sea freight solutions for large-volume orders. Your goods are securely packed and shipped in containers, ensuring cost-effective delivery to ports worldwide.

Air Freight

For faster delivery, our air freight service ensures your products reach international destinations quickly, with careful handling and full tracking along the way.

International Express

Need urgent shipments? Our international express service delivers small to medium orders efficiently, providing door-to-door service with real-time tracking for peace of mind.

Copper THHN/THWN-2 Wire for school building wiring

COOPERATIVE PARTNER

We are looking for a cooperative partner to expand our business.

THHN/THWN-2 copper building wire for commercial building wiring

THHN/THWN-2 copper building wire for industrial building wiring

THHN/THWN-2 copper building wire for residential building wiring

THHN/THWN-2 copper building wire for control panel wiring

THHN/THWN-2 copper building wire for distribution panel wiring

Copper THHN/THWN-2 Wire for industrial building wiring

Copper THHN/THWN-2 Wire for residential building wiring

Copper THHN/THWN-2 Wire for control panel wiring

Copper THHN/THWN-2 Wire for distribution panel wiring

Copper THHN/THWN-2 Wire for lighting circuits

How To Cooperate With Us?

Simply share your requirements, receive our professional solution, confirm samples, and enjoy fast, reliable production and worldwide delivery - working with us is that easy.

Our address

Building 2, No. 40 Luxi 2nd Road, Liaobu Town, Dongguan City, Guangdong Province, China

Phone Number

+86 136 6257 9592

+86 135 1078 4550

E-mail

manager01@greaterwire.com

THHN/THWN-2 copper building wire for lighting circuits

FAQ

What is the rated ampacity of 300 kcmil UL 83 copper THHN/THWN-2 wire?

Per NEC 310.15(B)(16), 300 kcmil copper THHN/THWN-2 has a 90°C ampacity rating of 320A in dry locations at 30°C ambient temperature. Note that mandatory ampacity derating applies when 3 or more current-carrying conductors are bundled in a single conduit or raceway, or when installed in high-ambient environments. Final sizing should always be verified by a licensed electrical engineer based on actual project conditions.

Can this 300 kcmil THHN/THWN-2 wire be installed underground?

Yes, it is suitable for underground installations when routed inside approved conduit or raceway, thanks to its THWN-2 wet-location 90°C rating, which withstands condensation and occasional water seepage. However, it is not rated for direct burial without protective conduit, as its nylon jacket does not provide sufficient mechanical protection against soil abrasion and corrosion.

Does this 300 kcmil THHN/THWN-2 wire comply with UL 83 and North American electrical codes?

Yes. This wire is manufactured and tested in strict accordance with UL 83 - the standard for thermoplastic-insulated building wires - and carries full THHN/THWN-2 ratings. Its construction and performance meet NEC requirements for commercial and industrial building wiring, making it a code-compliant specification for North American construction projects.

What stranding class does the copper conductor use, and is it suitable for long conduit pulls?

This 300 kcmil THHN/THWN-2 wire uses Class B concentrically stranded annealed copper conductor, the universal industry standard for building wire. Paired with a smooth, low-friction nylon outer jacket, it balances flexibility and mechanical durability, making it well-suited for long conduit runs and routing through elbows. The stranded construction reduces kinking and pulling tension compared to solid conductors in large gauges.

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