Wire

Industrial Wire Types: Part 1

THHN

Thermoplastic, High Heat resistant, Nylon jacket insulation (THHN) wire is used in conduit or in cable trays due to its rigidity and tough insulation characteristics. THHN can be stranded (several small strands of wire grouped together), allowing for more flexibility and less chance of breakage, or solid (one wire), which is more durable and rigid. THHN wire is suitable for use in dry locations with temperatures that do not exceed 90 degrees Celsius.

XHHW

Cross-linked polyethylene, High Heat-resistant, Water-resistant (XHHW) wire is very similar to THHN. The difference is that XHHW wire is overall a more durable wire that can withstand higher temperatures and is water resistant. XHHW wire can also be found in both stranded and solid wire options.

MTW

Machine Tool Wire (MTW) wire is much more flexible than THHN wire with insulation that is not as durable, making it a poor choice to run through conduit. The flexibility makes it ideal for winding through tight areas, such as wire ducting in an industrial control cabinet. MTW wire is almost exclusively found in stranded wire, which allows for much of the flexibility and reduces the chances of the wire breaking. MTW wire is intended for use in dry locations that do not exceed 90 degrees Celsius or wet locations that do not to exceed 60 degrees Celsius.