THHN, THWN and THW are all types of single conductor electrical wire used in homes and buildings to deliver power. Previously, THW THHN THWN was different wires with different approvals and applications. But Now, here is now a generic THHN-2 wire that covers all approvals for all variants of THHN, THWN and THW.
1. What is THW Wire ?
Thw wire stands for thermoplastic, heat- and water-resistant wire. It is made of copper conductor and PVC insulation. It is used for power and lighting circuits in industrial, commercial and residential facilities. This type of wire can be used in dry and wet places, its maximum temperature of operation is 75 ºC and its voltage of service for all the applications it is 600 V.
Also , the acronym THW is missing the “N” for nylon-coated. The nylon coating looks like a little piece of plastic and protects wires in a similar ways. Without the nylon coating, THW wire price is relatively cheap but it provides minimal protection against various environmental adversities.
THW Wire Strandard
• ASTM B-3: Copper Annealed or Soft Wires.• ASTM B-8: Copper Stranded Conductors in Concentric Layers, Hard, Semi-hard or Soft.
• UL - 83: Wires and Cables Insulated with Thermoplastic Material.
• NEMA WC-5: Wires and Cables Insulated with Thermoplastic Material (ICEA S-61-402) for Transmission and Distribution of Electric Power.
2. What is THWN THHN Wire?
THWN and THHN all adding the “N” in the acronymare, that means they are all nylon-coated wire. THWN wire is similar to THHN. THWN wire is water-resistant, adding the “W” into the acronym. THWN is better than THHN in water-resistant performance. THHN or THWN all can be used for power and lighting circuits in industrial, commercial and residential facilities, they are specially suitable for special installations through difficult ducts and to be used in abrasive zones or polluted with oils, grease, gasoline, etc. and other corrosive chemical substances as paints, solvents, etc.,
This type of conductor when it is used as THHN it can be used in dry places with maximum temperature of operation of 90 ºC, but if it is used as THWN-2 it can be used in dry and wet places with maximum temperature of operation of 90 ºC, likewise when they are exposed to oils, grease, paints, chemical solvents, etc., their maximum temperature of operation is 75 ºC. Regarding their voltage of service, for all the applications, it is of 600 V.
THWN THWN Wire Standards
• ASTM B-3:Copper Annealed or Soft Wires.
• ASTM B-8:Copper Stranded Conductors in Concentric Layers, Hard, Semi-hard or Soft.
• UL - 83:Wires and Cables Insulated with Thermoplastic Material.
• NEMA WC-5:Wires and Cables Insulated with Thermoplastic Material (ICEA S-61-402) for Transmission and Distribution of Electric Power.
3. How We Select Wire from THW THHN and THWN?
THW wire may be better if only for indoor environment. The cheaper thw wire can also decrease your cost . While THHN & THWN may more suitable for you in dry or wet outdoor environment.
