THHN-THWN2-600V
UL THHN / THWN-2 Building Wire, 600 V
600 V wire with a nylon jacket over the PVC, UL listed and marked THHN/THWN-2 for NEC projects.
A THHN wire is two layers doing two different jobs. The PVC underneath is the electrical insulation, and it carries the 600 V rating. The nylon jacket over it is only a tenth of a millimetre thick, but it is the layer that lets the wire be dragged through a metal conduit without the insulation being scored, and it is the layer that resists the oil and gasoline a UL 83 wire has to withstand.
The marking is what a North American or NEC-aligned project will check first. THHN alone is rated for dry locations; THWN-2 is the wet-location rating. A wire printed THHN/THWN-2 satisfies both and carries a 90 °C rating in wet and dry locations, which is what NEC 310.16 ampacity tables assume. Voltcore holds UL listing on this building wire and supplies 14 AWG to 750 kcmil.
Specification
| Item | Value |
|---|---|
| Rated voltage | 600 V |
| Size range | 14 AWG to 750 kcmil |
| Conductor | Class B stranded or solid copper, to ASTM B3 and B8 |
| Insulation | PVC, 0.38–1.52 mm nominal by size |
| Jacket | Nylon (polyamide), 0.10–0.20 mm nominal |
| Maximum conductor temperature | +90 °C dry, +90 °C wet for THWN-2 |
| Location rating | Dry for THHN, wet and dry for THWN-2 |
| Oil and gasoline resistance | Meets the oil resistant II requirements of UL 83 |
| Flame behaviour | Passes the VW-1 vertical flame test |
| Standard | UL 83, UL 758, NEC 310.16 |
| Marking | Size, type letter designation, 600 V, UL listing mark |
| Supply form | Coils, spools, or paralleled pulls in a container |
Layer-by-layer construction
Listed from the conductor outward. Read this alongside the specification table — the two together tell you whether the cable will survive its installation method.
- 1. ConductorClass B stranded or solid annealed copper to ASTM B3 and B8, 14 AWG to 750 kcmil
- 2. InsulationPVC compound, 0.38–1.52 mm nominal wall, applied concentric over the conductor
- 3. Nylon jacketPolyamide jacket, 0.10–0.20 mm nominal, extruded over the PVC for abrasion, oil and gasoline resistance
- 4. MarkingSurface print with size, THHN or THWN-2, 600 V, the UL listing mark and the manufacturer identification
Reference dimensions and weights
| Size (AWG or kcmil) | Nominal cross-section (mm²) | Stranding (n×mm) | Insulation thickness (mm) | Nylon jacket thickness (mm) | Approx. overall diameter (mm) | Approx. weight (kg/km) | Ampacity at 30 °C, 90 °C rating (A) |
|---|---|---|---|---|---|---|---|
| 14 | 2.08 | 19 × 0.38 | 0.38 | 0.10 | 2.8 | 23 | 25 |
| 12 | 3.31 | 19 × 0.47 | 0.38 | 0.10 | 3.2 | 33 | 30 |
| 10 | 5.26 | 19 × 0.60 | 0.51 | 0.10 | 4.0 | 52 | 40 |
| 8 | 8.37 | 19 × 0.75 | 0.76 | 0.10 | 5.1 | 84 | 55 |
| 6 | 13.3 | 19 × 0.96 | 0.76 | 0.10 | 5.9 | 120 | 75 |
| 4 | 21.2 | 19 × 1.20 | 1.02 | 0.13 | 7.4 | 190 | 95 |
| 2 | 33.6 | 19 × 1.52 | 1.02 | 0.13 | 8.7 | 280 | 130 |
| 1/0 | 53.5 | 19 × 1.89 | 1.27 | 0.15 | 10.7 | 440 | 170 |
| 2/0 | 67.4 | 19 × 2.13 | 1.27 | 0.15 | 11.7 | 545 | 195 |
| 4/0 | 107 | 37 × 1.92 | 1.27 | 0.15 | 14.1 | 840 | 260 |
Reference figures for preliminary sizing and drum planning. Overall diameter and weight vary with strand construction and sheath thickness tolerance; certified drawings are issued with each quotation.
Engineering characteristics
- UL listed to UL 83, which is the listing an NEC inspector looks for on the coil.
- Nylon jacket over the PVC takes the abrasion of a pull through metal conduit.
- Marked THHN/THWN-2, so the wire is rated for wet locations as well as dry.
- 90 °C rating, which is the column NEC 310.16 ampacity tables are built on.
- Passes the VW-1 vertical flame test and the oil resistant II requirements of UL 83.
- Sizes from 14 AWG to 750 kcmil, covering a lighting circuit and a service entrance.
- Class B stranded copper to ASTM B8, which is the stranding class the NEC expects.
Typical applications
- Branch circuit wiring in conduit in commercial and residential buildings
- Feeders and sub-feeders in industrial facilities
- Panel boards, switchboards and motor control centres
- Machine tool and industrial equipment wiring
- Data centre and office fit-out power distribution
- Projects in the Americas, the Philippines and other NEC-aligned markets
Ordering options
- 14 AWG to 750 kcmil, stranded or solid
- THHN/THWN-2 marking as standard; THHN-only marking on request
- Standard colours: black, white, red, blue, brown, green, grey, orange, yellow
- Coils, spools, or pulled parallel for a large feeder order
- Private-label printing and packaging for distributor programmes
Standards manufactured to
- UL 83
- ASTM B3
- ASTM B8
- NEC 310.16
- UL 1581 (VW-1)
Manufactured to other standards on request. Send the standard number with your RFQ and we will quote against it rather than against a near-equivalent.
Price and availability for UL THHN / THWN-2 Nylon-Jacketed Building Wire
Include cross-section, core count, voltage grade, route length and installation method — those five determine price more than anything else on the page.
- Engineer-reviewed before pricing
- Reference drawings issued with the quotation
- Free sample up to free sample up to 5 m
UL THHN / THWN-2 Nylon-Jacketed Building Wire — frequently asked questions
What is the difference between THHN and THWN-2?
THHN is the 90 °C dry-location rating. THWN-2 is the 90 °C wet-location rating. A single construction marked THHN/THWN-2 carries both, which is why that is the marking to ask for: it is accepted in conduit outdoors, underground in a raceway, and in any wet location, without a separate product.
Why does the nylon jacket matter?
It is the mechanical layer. A wire pulled through EMT or rigid metal conduit scores its insulation against the fittings, and the nylon takes that instead of the PVC. It also gives the oil and gasoline resistance UL 83 requires. A wire with PVC only is not a listed THHN wire, however good the insulation is.
How do I convert the size from mm² to AWG?
Give the nearest standard AWG or kcmil size rather than converting exactly. A 2.5 mm² conductor sits between 14 AWG and 12 AWG, and a 4 mm² between 12 AWG and 10 AWG. Round up, not down: for a circuit designed at 2.5 mm² the correct call is 12 AWG, taking the larger of the two.
Do you hold the UL listing for this wire?
Yes. UL is on Voltcore's certificate list and the building wire line is UL listed, so the wire carries the listing mark as well as the type letter designation print. For a project in the Americas, quote the size, the colour and the length and the listing reference will be supplied with the quotation.