MTW is a wiring type that often confuses many. We’ll go through what it consists of and can mean for you.
MTW stands for Machine Tool Wire. It is used mainly for wiring machine tools, certain appliances, and control cabinets. It contains a single piece of highly stranded copper as the bare conductor and is typically coated in PVC, making it highly flexible and suitable for hooking up.
What is Machine Tool Wire?
Uses
Machine Tool Wire, or MTW for short (also referred to as MTW/TEW wire), is made primarily for machine tools, as its name suggests.
It is also used in the internal wiring of control cabinets or panels. Their design makes them very versatile. They can resist moisture, oil, and gasoline very well and offer heat and corrosion protection.
Suitability
MTW wire has a typical voltage rating of 600V. They are particularly ideal for hot environments. They can tolerate up to 140°F (60°C) in humid environments or if exposed to oil or coolants, or 194°C (90°C) in dry environments.
Technical Specifications
MTW conforms to UL Standard 1063, which specifies a single or multi-conductor as a hookup wire covered by a PVC jacket. MTW wire also passes the VW-1 Flame Test and meets several UL-AWM styles, including 1007, 1015, 1028, 1283, and 1284.
Distinguishing Features
MTW wire is similar to AWM wire (Appliance Wiring Material).
Both types are used for the internal wiring of certain appliances and control cabinets. But MTW is intended to be used for industrial machine tools. MTW is covered under the standard UL-1063, whereas AWM is covered under UL-758 and is governed under NFPA-79.
MTW wire also shares some characteristics with but differs from THHN (Thermoplastic High Heat-Resistant Nylon). MTW and THHN are made according to NEC guidelines and are suitable for general-purpose wiring. But THHN is primarily used in the construction industry.
In gauge, MTW wire usually ranges from 22 AWG to 1000 MCM, whereas THHN wire also includes 14 to 20 AWG.
Different Types of MTW Wire
MTW wire differs by type (e.g., 1007, 1015, 1028, 1283, and 1284).
I will describe types UL-1007 and UL-1015 below.
MTW UL-1007
The UL-1007/1569 type of MTW wire is a stranded hookup wire.
It has stranded bare copper and is insulated with PVC. It is used for general-purpose wiring, machine tools and appliances, and control circuits that don’t exceed 300 volts.
The temperature rating for this type is 176°F-221°F (80°C- 105°C).
MTW UL-1015
The UL-1015 type of MTW wire is also a stranded hookup wire.
It has either stranded bare or tinned copper and is insulated with PVC. It is also used for general-purpose wiring, machine tools, appliances, and control circuits. But it has a higher voltage tolerance of 600 volts and a temperature rating of 221°F (105°C). There is an option to add helical wire stripes.
Also, it is sunlight- and UV-resistant.
References
MTW 18WHITE-Blue Stripe 500ft: https://rspsupply.com/p-139852-mtw-18white-blue-stripe-500ft.aspx.
300V Single Core UL 1007: https://mx.misumi-ec.com/en/vona2/detail/110500115640/?HissuCode=UL1007-28-W-305.
600V Single Core UL 1015: https://mx.misumi-ec.com/en/vona2/detail/110500115460/?HissuCode=UL1015-20-BE-305.
