MTW vs THHN Wire

In our This vs. That series, we are comparing (and contrasting) two seemingly similar products. A lot of products seem the same at first glance but can greatly affect the outcome of your next application. Today, we're taking a closer look at MTW and THHN wire. They are PVC hook-up wires used in building applications. Both are built in accordance with the National Electrical Code for general purpose wiring for installation in conduits or other recognized raceways. These cables share several overlapping characteristics, although there are a few distinct differences that set them apart.

What is MTW Wire?

MTW stands for Machine Tool Wire. It is primarily used for the wiring of machine tools, appliances, and control cabinets. It is a PVC hook-up wire constructed of a highly stranded bare copper conductor. This high stranding gives it more flexibility than the THHN building wire. Also available with a tinned copper conductor, MTW wires offer increased corrosion protection and moisture resistance. It is resistant to heat, moisture, oil, and gasoline. This type of wire almost always has a voltage rating of 600V and a maximum temperature of 105°C. Additionally, most machine tool wire passes the VW-1 Flame Test and meets several UL AWM styles, including 1015, 1028, 1283, and 1284. It is often double-listed as MTW/TEW wire.

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What is THHN wire?

THHN stands for Thermoplastic High Heat-Resistant Nylon. It is a building wire primarily used to carry electrical currents to external power sources. This wire consists of thermoplastic insulation (often Polyvinyl Chloride) and a nylon jacket. THHN wire has a voltage rating of 600V. It has a temperature range of up to 90°C in dry locations and 75°C in wet locations. This type of wire features either a bare copper or aluminum conductor and comes both stranded or solid, depending on the size. It is sometimes dual-listed as THHN/THWN wire.

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How Do They Compare?

Although the national electrical code lists both wires are suitable for use in similar applications, there are a few characteristics that set them apart. These differences can make a big difference when trying to decide which type of cable will best meet your needs.

Both can feature a bare copper conductor, but THHN is also available with an aluminum conductor and MTW wire is available with a tinned copper conductor. At its core, Machine Tool Wire offers a higher strand count in the conductor, making it more flexible. THHN wire also features a nylon coating that further restricts movement.

If you are unsure which wire would work best for your wire and cable needs, let us help you out! You can learn more about MTW and THHN wire through Allied University or contact us today.