Executive Summary: The "Big Three" of PVC Wire
Hook-up wire selection depends on voltage requirements, insulation thickness, and connector compatibility. UL 1007 is the standard 300V wire with standard PVC insulation. UL 1015 is the high-voltage (600V) alternative with thicker insulation (often double the thickness). UL 1061 is a space-saving 300V wire using Semi-Rigid PVC (SR-PVC), designed specifically for high-density bundles and IDC connectors.
Key Engineering Rules of Thumb:
- The IDC Rule: If you are using Insulation Displacement Connectors (like ribbon cable connectors), specify UL 1061. Its semi-rigid insulation is designed to be cut cleanly by the connector blades; standard UL 1007 is often too soft and thick, leading to poor termination.
- The Voltage Rule: For AC Mains (120V/240V) internal wiring, UL 1015 is the industry standard due to its 600V rating and 105°C thermal rating.
- The Space Rule: UL 1061 reduces bundle diameter by ~20% compared to UL 1007. Use it when routing wires through tight hinges or small conduits.
Technical Deep Dive: Insulation Physics and AWM Styles
Appliance Wiring Material (AWM) styles define the safety limits of the wire. While all three use PVC, the formulation and wall thickness dictate their mechanical and electrical performance.
1. UL 1007: The General Purpose Standard
This is the "default" hook-up wire found in most low-voltage electronics.
- Specs: 300V, 80°C rating.
- Insulation: Extruded PVC, typically 0.016" (16 mils) wall thickness.
- Best Use: Internal wiring of appliances, control panels, and point-to-point wiring where space is not critically limited and voltage is low (24V DC logic).
2. UL 1015 (MTW/TEW): High Voltage & Heat
Often referred to as MTW (Machine Tool Wire) or TEW (Thermoplastic Equipment Wire) in dual-rated versions.
- Specs: 600V, 105°C rating.
- Insulation: Thicker PVC, typically 0.030" (30 mils) wall thickness.
- Durability: The thicker wall provides better abrasion resistance and higher dielectric strength, making it safe for carrying mains power inside chassis.
- Best Use: Power supplies, AC power distribution, and industrial control cabinets.
3. UL 1061: High Density & Semi-Rigid
The critical differentiator here is SR-PVC (Semi-Rigid Polyvinyl Chloride). It is harder and tougher than standard PVC.
- Specs: 300V, 80°C rating.
- Insulation: Thin-wall SR-PVC, typically 0.009" (9-10 mils) wall thickness.
- Mechanics: Because the insulation is thinner but harder, it resists "crush" better than UL 1007. It allows for much smaller harness diameters.
- Best Use: IDC Terminations, high-density computer wiring, business machines, and applications where standard PVC is too bulky.
Comparison Data: UL Style Matrix
|
Feature |
UL 1007 |
UL 1015 |
UL 1061 |
|---|---|---|---|
|
Voltage Rating |
300V |
600V |
300V |
|
Temp Rating |
80°C |
105°C |
80°C |
|
Insulation Material |
PVC (Standard) |
PVC (Standard) |
SR-PVC (Semi-Rigid) |
|
Wall Thickness (Typ) |
0.016" (16 mils) |
0.030" (30 mils) |
0.010" (10 mils) |
|
Abrasion Resistance |
Fair |
Good |
Fair (but tough) |
|
Primary Application |
General Low Voltage |
AC Mains / Industrial |
IDC / High Density |
|
Cost |
Low |
Moderate |
Moderate |
Frequently Asked Questions (FAQ)
Can I use UL 1007 for IDC connectors?
Proceed with caution. Most IDC connectors (like 0.100" pitch headers) are specifically designed for the wire diameter and hardness of UL 1061. Using UL 1007 (which has a thicker, softer insulation) can strain the plastic housing or result in the insulation not being fully pierced, leading to intermittent connectivity. Always check the connector datasheet for "Applicable Wire OD."
Why is UL 1015 so much thicker than UL 1007?
The thickness is required to meet the 600V dielectric breakdown requirement. To safely contain higher voltage without arcing, the insulation wall must be physically thicker (approx. 30 mils vs 16 mils). This makes UL 1015 stiffer and bulkier, which is why it is not used for delicate logic signals.
What is the difference between PVC and SR-PVC?
PVC (Polyvinyl Chloride) is flexible and soft. SR-PVC (Semi-Rigid PVC) has a different plasticizer formulation that makes it harder and more resistant to cut-through, even with a thinner wall. This "hardness" is what allows UL 1061 to be so thin (space-saving) while still passing UL safety tests for 300V.
Is UL 1015 the same as MTW?
Often, yes. Many wire manufacturers produce a single wire that is dual- or tri-rated as UL 1015 / UL 1230 / MTW (Machine Tool Wire). This simplifies inventory. However, "MTW" specifically refers to a standard used in the National Electrical Code (NEC) for industrial machinery, whereas "UL 1015" is an Appliance Wiring Material (AWM) style. Always check the print string on the wire.
About the Author
Michael Wang
Senior Technical Engineer
As the technical lead at TeleWire, Michael bridges the critical gap between complex engineering requirements and precision manufacturing. With deep expertise in Design for Manufacturing (DFM) and signal integrity, he oversees the technical validation of custom interconnect solutions for mission-critical automotive, industrial, and medical applications.
