Professional cable manufacturer
UL 83 · UL 1063 (MTW) · 600V · ASTM B787
THHN 12 AWG Stranded Copper Building Wire
19-strand bare annealed copper building wire with PVC insulation and a nylon jacket — for branch circuits, feeders and control wiring pulled through conduit and raceway in commercial and industrial buildings.
600V
Rated Voltage
+90°C dry
+75°C wet (THHN)
19-strand
Bare Copper
12 AWG
3.31 mm² nominal
↓ Download Datasheet (PDF)
UL 83 / UL 1063 (MTW)
VW-1 flame rated
Sample orders available
OEM colours & packing
THHN BUILDING WIRE · 12 AWG
UL 83THHN / THWN-2 wire
UL 1063MTW, stranded only
ASTM B78719-wire combination unilay
NEC 310.1620 / 25 / 30 A at 60 / 75 / 90°C
600V · +90°Cdry; +75°C wet
Key Specifications
The essentials, at a glance
Everything an electrical contractor or inspector checks first — before diving into the full datasheet below.
600V
Rated voltage, UL 83
19 strands
Combination unilay, ASTM B787
PVC + Nylon
Insulation + jacket
+90°C dry
+75°C wet (THHN) / +90°C wet (THWN-2)
20 / 25 / 30 A
NEC 310.16, 60 / 75 / 90°C columns
23 lb/1000 ft
Approx. weight (≈36 kg/km)
Product Overview
The 600V workhorse behind a 12 AWG circuit
The THHN 12 AWG Stranded Copper Building Wire is a single-conductor, 600V thermoplastic-insulated building wire manufactured to UL 83. The same construction is printed and listed as THWN-2, so one spool covers dry and wet locations in conduit, raceway, cable tray and machine-tool wiring. The nominal cross-section is 3.31 mm².
The conductor is 19 strands of soft annealed bare copper, stranded combination unilay to ASTM B787 — a compact 2.35 mm stranded conductor (19 × 0.47 mm) that pulls easily through bends and terminates reliably under a lug or wire nut. PVC insulation of 0.38 mm (0.015 in) is covered by a 0.10 mm (0.004 in) nylon jacket; the finished stranded wire measures 3.5 mm (0.140 in) overall and weighs about 23 lb/1000 ft (≈36 kg/km).
Ampacity follows NEC Table 310.16, which lists 20 A at 60°C, 25 A at 75°C and 30 A at 90°C for not more than three current-carrying conductors in a raceway or cable at 30°C ambient. The 90°C figure is not a free upgrade: under NEC 110.14(C) the conductor ampacity may not exceed the lowest temperature rating of any connected termination, conductor or device, and for 12 AWG copper the branch-circuit overcurrent protection is also capped at 20 A by NEC 240.4(D). The 90°C column is used only for ampacity adjustment and correction.
Two resistance values matter and they are not interchangeable. The 20°C calculated value is 5.21 Ω/km — ideal copper resistivity over the nominal cross-section, useful for comparing constructions. The value to use for voltage drop and code work is the NEC Chapter 9 Table 8 figure for stranded uncoated copper at 75°C: 1.98 Ω/1000 ft, about 6.50 Ω/km.
THHN is rated +90°C in dry locations and +75°C in wet locations, while the THWN-2 listing covers +90°C dry and wet and +75°C where the wire is exposed to oil. The construction is not listed for direct burial, so route it in a raceway or select a direct-burial-listed cable. A 12 AWG conductor is the smallest size that may be used on a general 20 A branch circuit, and it is the size most commercial lighting and receptacle circuits are designed around.
More about the manufacturer: About SORIVO →
Key Features
Eight features that matter on a 12 AWG pull
UL 83 / UL 1063 (MTW)
Manufactured to UL 83 for thermoplastic-insulated wire and listed as MTW to UL 1063 for stranded constructions used in machine-tool and control panel wiring.
19-Strand Bare Copper
Soft annealed bare copper, 19 strands stranded combination unilay to ASTM B787 — a 2.35 mm conductor with the flexibility solid wire cannot match.
PVC Insulation + Nylon Jacket
0.38 mm (0.015 in) PVC insulation under a 0.10 mm (0.004 in) nylon jacket — 600V dielectric strength with the abrasion and cut-through resistance a pull through steel conduit demands.
600V, +90°C Dry
Rated 600V for all applications: +90°C in dry locations, +75°C wet as THHN, and +90°C in both dry and wet locations as THWN-2.
VW-1 Flame Rated
Vertical wire flame test to UL 1581. VW-1 applies to all sizes of this construction, including 12 AWG.
NEC 310.16 Ampacity, Correctly Applied
20 A at 60°C, 25 A at 75°C and 30 A at 90°C per NEC 310.16, published together with the NEC 110.14(C) termination limit and the 20 A practical circuit ampacity — so the number on this page matches the number in the panel.
Two Labelled DC Resistances
5.21 Ω/km at 20°C, stated as a calculated value, and the NEC Chapter 9 Table 8 value at 75°C of 1.98 Ω/1000 ft (≈6.50 Ω/km) — never blended into one number.
Eleven Standard Colours
Black, white, red, blue, green, yellow, gray, brown, orange, violet and pink, supplied on spool, coil or reel with OEM colour and packing options.
Applications
Where 12 AWG THHN / THWN-2 goes
From a lighting branch circuit to a machine-tool panel — one construction, sized per circuit.
01
Branch Circuits
20 A branch circuits for receptacles, lighting and small equipment — the classic 12 AWG application in commercial buildings.
02
Panelboards & Feeders
Panelboard and load-centre terminations and short feeders inside electrical rooms, where a compact 3.5 mm wire keeps conduit fill workable.
03
Lighting Circuits
Lighting branch circuits and switch legs in office, retail and warehouse space, pulled in EMT, IMC or PVC conduit.
04
Control & Signal Wiring
Control, relay and signal circuits inside enclosures and wireways, where the MTW listing and flexible stranding simplify routing.
05
HVAC & Mechanical Equipment
Disconnects, contactors and motors on rooftop units and air handlers, terminated in equipment rated for the application.
06
Machine Tool & Panel Wiring
Machine-tool and industrial control panel wiring under the UL 1063 (MTW) listing, which applies to stranded constructions.
07
Industrial Plants & Warehouses
Long raceway runs where lubricated pulls and a consistent 3.5 mm outside diameter keep installation time predictable.
08
Renovation & Retrofit Pulls
Rewires and tenant fit-outs where existing conduit is tight and a 19-strand conductor bends and pulls more easily than solid wire.
Technical Specifications
Full specification sheet
The complete parameter set — the same data our engineers quote from.
Table 1 Dimensions, weight, resistance and ampacity by size
| AWG size | Strands count | Conductor dia. stranded, mm | PVC insulation mm (in) | Nylon jacket mm (in) | Overall dia. mm (in) | Weight lb/1000 ft (kg/km) | DC resistance 20°C calc., Ω/km | DC resistance 75°C, Table 8, Ω/1000 ft | Ampacity 60°C, A | Ampacity 75°C, A | Ampacity 90°C, A |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 12 | 19 | 2.35 | 0.38 (0.015) | 0.10 (0.004) | 3.5 (0.140) | 23 (36) | 5.21 | 1.98 | 20 | 25 | 30 |
| 10 | 19 | 3.00 | 0.51 (0.020) | 0.10 (0.004) | 4.3 (0.170) | 38 (57) | 3.28 | 1.24 | 30 | 35 | 40 |
| 8 | 19 | 3.75 | 0.76 (0.030) | 0.13 (0.005) | 5.6 (0.230) | 62 (94) | 2.06 | 0.778 | 40 | 50 | 55 |
The highlighted 12 AWG row is the size this page covers. Ampacity values are NEC Table 310.16 for not more than three current-carrying conductors in a raceway or cable at 30°C ambient. The 90°C column is permitted for ampacity adjustment and correction only, per NEC 110.14(C) — it does not raise the ampacity of a circuit whose terminations are rated 60°C or 75°C. The 20°C resistance is a calculated value derived from ideal copper resistivity over the nominal cross-section and is not the NEC Chapter 9 Table 8 figure, which is listed at 75°C for stranded uncoated copper. Dimensions are nominal and subject to manufacturing tolerance.
Table 2 Construction and performance parameters
| General Information | |
| Product Name | THHN 12 AWG Stranded Copper Building Wire (single conductor, stranded) |
| Product Type | THHN / THWN-2 thermoplastic-insulated building wire |
| AWG Size | 12 AWG — 3.31 mm² nominal cross-section |
| Primary Standard | UL 83 — thermoplastic-insulated wires and cables |
| Further Standards | UL 1063 (MTW); ASTM B787 and ASTM B3; CSA C22.2 No. 75 |
| Certification | UL 83 / UL 1063 (MTW) / CSA C22.2 No. 75 (c-UL T90 Nylon, TWN75) / RoHS — scope confirmed against the certificate for the selected construction |
| Rated Voltage | 600V |
| Conductor | |
| Conductor Material | Soft annealed bare copper |
| Stranding | 19 strands, combination unilay per ASTM B787 |
| Conductor Diameter (Stranded) | 2.35 mm (19 × 0.47 mm); solid version 2.05 mm |
| Max. DC Resistance @20°C (calculated) | 5.21 Ω/km — calculated from ideal copper resistivity over the 3.31 mm² nominal cross-section |
| Max. DC Resistance @75°C (NEC Ch.9 Table 8) | 1.98 Ω/1000 ft ≈ 6.50 Ω/km for stranded uncoated copper |
| Insulation & Jacket | |
| Insulation Material | PVC (polyvinyl chloride) |
| Insulation Thickness | 0.38 mm (0.015 in) |
| Jacket Material | Nylon (polyamide) |
| Jacket Thickness | 0.10 mm (0.004 in) |
| Overall Diameter (Stranded) | 3.5 mm (0.140 in) |
| Weight | ≈ 23 lb/1000 ft (≈ 36 kg/km) |
| Available Colours | Black, White, Red, Blue, Green, Yellow, Gray, Brown, Orange, Violet, Pink |
| Colour Rules | Green is used for equipment grounding and white or gray for the grounded conductor, per NEC 250.119 and 200.6 |
| Electrical Ratings | |
| Ampacity (NEC 310.16) | 20 A at 60°C / 25 A at 75°C / 30 A at 90°C — not more than three current-carrying conductors in a raceway or cable, 30°C ambient |
| Practical Circuit Ampacity | 20 A — limited by the NEC 110.14(C) termination temperature rule and by the NEC 240.4(D) overcurrent protection limit for 12 AWG copper |
| Use of the 90°C Column | Permitted for ampacity adjustment and correction only, per NEC 110.14(C) — the corrected ampacity may not exceed the column matching the terminations |
| Referenced Tables | NEC Table 310.16 (formerly 310.15(B)(16)); see also NEC 310.15 and 110.14(C) and 240.4(D) |
| Temperature & Environmental | |
| Temperature Rating (THHN) | +90°C dry / +75°C wet |
| Temperature Rating (THWN-2) | +90°C dry and wet; +75°C where the wire is exposed to oil |
| Flammability | VW-1 vertical wire flame test per UL 1581 |
| Oil Resistance | Gasoline and oil resistant II, as covered by the UL 83 / UL 1063 listing of this construction |
| Moisture Resistance | Wet-location rated through the THWN / THWN-2 designations of UL 83 |
| Abrasion Resistance | Nylon jacket provides high abrasion and cut-through resistance during pulling |
| Sunlight Resistance | Not claimed for this construction — for outdoor exposure run the wire in a raceway or select a sunlight-resistant listed cable |
| Direct Burial | Not listed for direct burial — use a raceway, or select a direct-burial-listed cable (UF / USE) |
| Tray Ratings | FT4 / IEEE 1202 tray ratings are not claimed for 12 AWG |
| Packaging & Logistics | |
| Packaging | Spool / Coil / Reel |
| Standard Lengths | 100 ft / 500 ft / 1000 ft per spool |
| MOQ | 1 spool (sample order available) |
| Lead Time | 5–15 working days (stock: 3–5 days) |
Final selection should be based on circuit loading, overcurrent protection, ambient temperature, conduit fill, voltage drop and the temperature rating of the terminations actually used. Our engineers confirm the construction, colour and certification scope against your project data.
Certificates & Standards
Verify before you buy — we make it easy
UL 83 / UL 1063 (MTW)
UL 83 is the standard for thermoplastic-insulated wire; UL 1063 is the machine-tool wire listing carried by the same stranded construction. Certificate of conformity available on request.
Request certificate copy →CSA C22.2 No. 75
The Canadian standard behind the c-UL T90 Nylon and TWN75 designations, carried on the same 600V wire for projects that specify CSA alongside UL.
Request test report →VW-1 Flame & RoHS
VW-1 vertical flame rating to UL 1581 and RoHS compliance, both applying to 12 AWG. FT4 / IEEE 1202 tray ratings are not claimed for this size.
Request test report →
Transparency note: certification status and exact scope should always be confirmed against the certificate for the selected wire construction. We provide the certificate and test reports with every quotation — no blank promises.
Quality & Factory
Made in a real cable factory, tested before it ships
Every spool of THHN / THWN-2 building wire is produced under controlled processes and released against the applicable UL 83 requirements.
- 1Incoming material control — bare copper wire and PVC and nylon compounds are checked before production starts.
- 2In-line process monitoring — strand count, conductor diameter, insulation concentricity and jacket thickness are tracked during extrusion.
- 3Routine electrical tests — on-line spark test plus finished-wire voltage, insulation-resistance and conductor-resistance tests: 5.21 Ω/km is checked against the 20°C calculated limit.
- 4Batch documentation — conductor resistance, dimensions, colour and test records are retained for every production batch.
19+
countries served
60+
building & industrial projects
100%
routine test before shipment
How to Order
From inquiry to loaded spool in 5 steps
Send Inquiry
Tell us the size (12 AWG), colour, quantity and destination market.
Confirm Construction
We confirm stranding, insulation and jacket build, certification scope and quotation within one working day.
Sample Evaluation
Sample for qualification — stock sizes usually ship from existing spools within a few working days.
Bulk Production
5–15 working days lead time, with batch test documentation.
Delivery & Support
Spool, coil or reel packing, shipping documents and after-sales support.
FAQ
Questions buyers ask before ordering
They are temperature and location ratings carried by the same wire. THHN is rated +90°C in dry locations; THWN is +75°C in wet locations; THWN-2 is +90°C in both dry and wet locations, and +75°C where the wire is exposed to oil. Sorivo supplies the construction printed as THHN / THWN-2, so one spool covers dry and wet raceway work at 600V.
NEC Table 310.16 gives 20 A at 60°C, 25 A at 75°C and 30 A at 90°C for not more than three current-carrying conductors in a raceway or cable at 30°C ambient. What the circuit can actually carry is lower: NEC 110.14(C) caps the conductor ampacity at the lowest temperature rating of the connected terminations and devices, and for 12 AWG copper the branch-circuit overcurrent protection is capped at 20 A by NEC 240.4(D). In practice this is a 20 A circuit, and the 90°C column is used only for ampacity adjustment and correction.
Because the insulation rating is not the circuit rating. NEC 110.14(C) requires the temperature rating used for ampacity to be coordinated with — and not higher than — the lowest temperature rating of any connected termination, conductor or device. Most breakers and devices rated 100 A or less are marked for 60°C or 75°C terminations. The 90°C column still matters: it may be used for ampacity adjustment and correction, but the corrected value may not exceed the column that matches the terminations.
Two figures, and they are not interchangeable. The 20°C calculated value is 5.21 Ω/km, derived from ideal copper resistivity over the 3.31 mm² nominal cross-section — useful for comparing constructions. The value to use for voltage drop and code work is the NEC Chapter 9 Table 8 figure for stranded uncoated copper at 75°C: 1.98 Ω/1000 ft, about 6.50 Ω/km.
Outdoors, yes — provided the wire is installed in a raceway or another approved enclosure, because the THWN-2 rating covers wet locations at +90°C. Direct burial is not supported: THHN / THWN-2 is a wet-location conductor, not a direct-burial cable, and it is not listed for that use. For a direct-burial run choose a UF or USE listed cable, or provide a raceway.
It depends on the circuit. The NEC 310.16 columns at 60 / 75 / 90°C are 20 / 25 / 30 A for 12 AWG, 30 / 35 / 40 A for 10 AWG and 40 / 50 / 55 A for 8 AWG, and the practical circuit ampacities on 60°C and 75°C terminations are 20 A, 30 A and 50 A respectively. A 12 AWG conductor is the smallest size that may be used on a general 20 A branch circuit, and it is the size most commercial lighting and receptacle circuits are designed around. For long runs the deciding factor is usually voltage drop rather than ampacity. Send us the load, the run length and the terminations and we will confirm the size.
Yes. Certificate and test documentation is provided with the quotation and with the shipment, and the exact scope is always confirmed against the certificate for the selected construction before the order is placed. Sample orders are available, and stock sizes usually ship from existing spools. We would rather show you the document than describe it — request it through the form below.
THHN / THWN-2 is the UL 83 conductor for raceway wiring in North American projects. If your project is instead specified to the European BS 6004 / IEC 60227 single-core PVC range — 6491X H07V-R — we supply that construction as well: PVC Single Core Cable 6491X H07V-R. The two families serve different markets; tell us the destination and we will quote the one your inspector expects.
Need a sample of 12 AWG THHN for your project?
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Get a Free Quote
Send your building wire requirement
The more detail you give, the faster and more accurate our quotation. Our engineers reply within one working day.
- Cross-section (12 AWG or another size) and quantity in ft or m
- Colour: black, white, red, green or another standard colour
- Application: branch circuit, feeder, panelboard or control wiring
- Termination temperature rating, if the circuit is being engineered
- Destination market (US, Canada or other) and sample request, if needed
Inquiry received
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