Evaluate the safety and performance of wire and cable components and compounds

The compounds used in wire and cable products can impact the overall product performance. As part of UL Solutions' trusted Plastics Material Recognition Program, our Wire and Cable Material Recognition Program can help drive customer confidence by evaluating materials against applicable standards. Using UL Recognized Components, you may be able to eliminate the need for additional material testing for some certifications, saving you time and money.

Our Wire and Cable Material Recognition Program certifies compounds under the following categories:

    QMTT2: Polymeric Materials for Use in Wire, Cable and Flexible Lighting Products
    QMTM2: Plenum Cable Compounds
    QMTN2: Polymeric Materials for Use in Appliance Wiring Material
    AATJ2: Acid Gas, Acidity and Conductivity of Combusted Materials and Assessment of Halogens
    TEPZ2: Restricted-use Substances for Use in Wire and Cable Components

For a full list of materials and compounds within each category, please refer to UL Product iQ®.
How UL Solutions' Wire and Cable Material Recognition Program can help you

Our Wire and Cable Material Recognition Program helps industry professionals quickly source or specify wire and cable compounds and materials that meet their compliance needs and project specifications. Use the UL Component Recognition Mark to help communicate performance-related properties to customers or determine if a compound component meets your needs.

Using UL Recognized Components, identifiable through the UL Component Recognition Mark, may help save time and money for the following roles:

    Cable manufacturer
    Product designer
    Procurement engineer
    Compliance director
    Specifier

Upon successful evaluation through the program, customers can promote the safety and quality of their products to their existing and potential customers. Products evaluated in the Plastics Material Recognition Program are listed in the Product iQ database, which thousands of designers, engineers and suppliers use to find providers of recognized materials and components. 
QMTT2: Evaluation of thermoplastic materials

Polymeric materials categorized as QMTT2 are used in wire, cable and flexible lighting products. Among the UL certification tests, we conduct various identification tests to assess if the compound has changed over time.
Products that use QMTT2 thermoplastic materials

Thermoplastic materials categorized as QMTT2 are typically intended for outdoor use. Finished products that incorporate these materials include:

    Power cords – typically bearing the W suffix in the type designation and tested in accordance with UL 62, the Standard for Flexible Cords and Cables
    Building wire used outdoors, in wet locations or where subject to oil or gasoline exposure – tested in accordance with UL 83, the Standard for Thermoplastic-Insulated Wires and Cables
    Thermoset materials such as ethylene-propylene continuous vulcanization (EPCVs) and cross-linked (XL) polymers used in:
        Thermoset-insulated wires – tested in accordance with UL 44, the Standard for Thermoset-Insulated Wires and Cables
        Cables using thermoset-insulated conductors – tested in accordance with UL 854, the Standard for Service-Entrance Cables
        Photovoltaic cables – tested in accordance with UL 4703, the Standard for Photovoltaic Wire 

Other cable types may also use QMTT2 compounds.

If a QMTT2 Recognized compound is used, certain tests may be omitted during the certification of finished cables. The eliminated tests include:

    Sunlight resistance
    Long-term insulation resistance in water
    Oil resistance
    Gasoline resistance

QMTM2: Evaluation of plenum cable compounds

Compounds categorized as QMTM2 are used to manufacture plenum-rated cables. We analyze the compound composition; we do not conduct any safety or performance testing of the finished cable product.

NFPA 262, the Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces, requires a composition characteristic analysis of the sheath and insulation/buffer layer. If you select a QMTM2-certified material to manufacture a plenum-rated cable, you eliminate the need to perform the composition identification step of the finished cable certification process.
Testing scope for compound characterization

Depending on the material, we perform one or more of the following tests to characterize the compound: 

    Infrared (IR) qualitative analysis 
    Thermogravimetric analysis (TGA) 
    Inductively coupled plasma (ICP) 
    Atomic absorption (AA) spectroscopy 
    Chlorine/bromine content 
    Differential scanning calorimetry (DSC) 
    Melt flow 
    Specific gravity (SG) 

QMTN2: Evaluation of polymeric materials for appliance wiring material

Polymeric materials for use in appliance wiring material (AWM) that has passed the applicable UL 758, the Standard for Appliance Wiring Material (AWM) tests can be recognized as a QMTN2 certified material. If extruded correctly, an AWM using a QMTN2 compound will fulfill the certification requirements in UL 758, the Standard for Appliance Wiring Material.

The use of a QMTN2 compound does not reduce the test program. However, wire manufacturers using a commercially available compound can apply for QMTN2 and AVLV2 files simultaneously. Upon successfully completing the UL Solutions evaluation, you will receive two certifications with one test program.
AATJ2: Evaluation of halogen content in combustible materials

This program evaluates halogen content in wire and cable construction materials in accordance with UL 2885, the Outline of Investigation for Acid Gas, Acidity and Conductivity of Combusted Materials and Assessment of Halogens. When a cable is constructed with all halogen-free combustible materials, e.g., insulation, fillers and jackets, the cable may be surface marked with the suffix "-HF."
TEPZ2: Evaluation of the presence of RoHS restricted substances

This program evaluates the presence of the Restriction of Hazardous Substances Directive (RoHS) restricted substances in all components of a cable. This is in accordance with UL 746R, the Outline of Investigation for Restricted Use Substances in Polymeric Materials, for nonmetallic components, and UL 1368, the Outline for Investigation for Restricted Use in Metallic Components. 

These compounds and components are covered under the Recognized component category TEPZ2. UL Certified wire and cables marked "-RoHS" are manufactured using these Recognized Components. Cable components include:

    Insulation and jacket materials
    Fillers
    Tapes
    Metallic conductors, armors and shields

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Test Procedures

QUALITATIVE INFRARED ANALYSIS (QIA) – The infrared (IR) spectrum for each material is obtained by means of a Fourier-transform infrared (FTIR) spectrometer as described in the Infrared Spectroscopy sections of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581, or the Standard for Polymeric Materials – Short Term Property Evaluations, UL 746A.

THERMOGRAVIMETRY (TGA) – A thermal curve of each material is obtained by means of a thermal analyzer with a thermogravimetric module. The test method is described in the Standard Test Method for Rapid Thermal Degradation of Solid Electrical Insulating Materials by Thermogravimetric Method, ASTM D 3850, except that the specimen is to be heated at 20°C (36°F) per minute in a nitrogen atmosphere. The upper temperature limit is material dependent, with 650°C as the minimum. The purge gas is not changed to air for the percent ash determination. This analysis is further described in the Thermogravimetry sections of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581, or the Standard for Polymeric Materials – Short Term Property Evaluations, UL 746A

ELEMENTAL ANALYSIS (EA) – The elements of interest are to be quantified for each material using microwave assisted sample preparation techniques employing acid digestion or, if appropriate, methods similar to those described for polyvinyl chloride (PVC) compounds in the Elemental Analysis section of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581, (or by other means) using an atomic absorption (AA) spectrophotometer or Inductively Coupled Plasma (ICP) spectrometer instrumentation, or both


DIFFERENTIAL SCANNING CALORIMETRY (DSC) – A thermal curve is to be obtained by means a Differential Scanning Calorimeter (DSC). The test method is described in the Standard Test Method for Transition Temperatures of Polymers by Differential Scanning Calorimetry, ASTM D 3418, except that the specimen is to be heated at 20°C (36°F) per minute in a nitrogen atmosphere without a preliminary thermal cycle. The upper temperature limit is typically 300°C, but may be adjusted depending on the material degradation and melt temperatures. This analysis is further described in the Differential Scanning Calorimetry sections of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581, and the Standard for Polymeric Materials – Short Term Property Evaluations, UL 746A.

ASH CONTENT – The ash content is to be determined using the direct-calcination procedure (Method A) described in ISO 3451-89, Part 5, covering methods for the ash-content analysis of polyvinyl chloride (PVC) materials. This analysis is further described in the Determination of Ash Content section of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581.

GEL PERMEATION CHROMATOGRAPHY (GPC) – Gel Permeation Chromatography (GPC) is to be performed for PVC materials using liquid chromatography that employs a porous gel as a separation medium. This method is designed to analyze the organic-soluble non-resin PVC compound components (for example, plasticizers) that appear within the working range of the column bank. This analysis is further described in the Gel Permeation Chromatography section of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581.

HALOGEN CONTENT – Tube furnace combustion/ion chromatography (IC), combustion ion chromatography (C-IC), X-ray fluorescence spectrometry (XRF) or Beilstein testing may optionally be performed to confirm presence or absence of halogen elements.

CHLORINE/BROMINE CONTENT – The halogen content of interest to be quantified for each material is to be obtained using a combustion flask sample digestion technique and apparatus essentially similar to that described in the Standard Test Method for Chlorine, Bromine, or Iodine in Organic Compounds by Oxygen Flask Combustion, ASTM E 442, or other equivalent means. Quantitation is then carried out by either vacuum UV Inductively Coupled Plasma (ICP) spectrometer instrumentation, ion chromatography (IC) or silver nitrate titration.

MELT FLOW – melt flow rate of each material is to be obtained by means of a melt flow indexer/extrusion plastometer using the method described in the Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer, ASTM D 1238.

SPECIFIC GRAVITY – The specific gravity of each material is to be obtained by means of an analytical balance using the method described in the Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement, ASTM D 792, or by other, equivalent means.

Underwriters Laboratories (UL) is a globally recognized organization that evaluates the safety and performance of electrical cables. Specific classifications like **QMTT2**, **QMTM2**, **QMTN2**, **AATJ2**, and **TEPZ2** denote different cable types and their compliance with safety and application standards.

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1. Understanding the Classifications

1. **QMTT2:**
   - Cables classified under **QMTT2** are evaluated as:
     - Thermoplastic insulated.
     - Flexible for general-purpose wiring.
     - Rated for use in residential, commercial, or industrial environments.
   - **Standards Tested:**
     - Flammability, heat resistance, and insulation integrity.

2. **QMTM2:**
   - These are shielded cables designed for:
     - Communication and signal transmission.
     - Specific environments requiring EMI (electromagnetic interference) protection.
   - **Standards Tested:**
     - Shielding effectiveness.
     - Dielectric strength.

3. **QMTN2:**
   - Low-voltage power cables designed for light-duty applications.
   - **Standards Tested:**
     - Voltage withstand capability.
     - Resistance to moisture and temperature variations.

4. **AATJ2:**
   - Cables classified under **AATJ2** are:
     - Armored and insulated for protection in harsh environments.
     - Designed for industrial applications where mechanical stress is expected.
   - **Standards Tested:**
     - Armor integrity.
     - Resistance to crushing and abrasion.

5. **TEPZ2:**
   - Specialty cables, often designed for:
     - High-temperature applications.
     - Usage in extreme conditions like chemical exposure or high mechanical wear.
   - **Standards Tested:**
     - High-temperature performance.
     - Chemical resistance.

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2. Key UL Safety Tests for These Classifications

1. **Flammability Testing:**
   - Ensures cables resist fire spread.
   - Tests include:
     - **Vertical Flame Testing (UL 1581):** Evaluates flame propagation on vertically mounted cables.
     - **Horizontal Flame Testing:** Assesses flame resistance for cables laid horizontally.

2. **Temperature Resistance:**
   - Cables are exposed to high and low temperatures to ensure insulation integrity:
     - **Cold Bend Test:** Tests flexibility at low temperatures.
     - **Heat Aging Test:** Ensures performance at elevated temperatures.

3. **Voltage Testing:**
   - Verifies the cable's ability to withstand voltage stresses:
     - **Dielectric Strength Testing:** Measures insulation's ability to resist breakdown under high voltage.
     - **Withstand Voltage Testing:** Ensures no short circuit occurs at rated voltage.

4. **Mechanical Durability:**
   - For armored or heavy-duty cables (e.g., **AATJ2**), tests include:
     - Crushing resistance.
     - Abrasion resistance.

5. **Moisture and Chemical Resistance:**
   - Cables exposed to moisture and chemicals are tested for:
     - Water absorption.
     - Corrosion resistance (for armored cables like **AATJ2**).

6. **EMI Shielding Effectiveness:**
   - For shielded cables like **QMTM2**, tests ensure the shielding protects against electromagnetic interference.

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3. Why UL Certification is Critical

1. **Ensures Safety:**
   - UL-certified cables meet strict safety standards, reducing risks of fire, electrical shock, or mechanical failure.

2. **Improves Reliability:**
   - UL testing ensures cables perform consistently in their intended applications, even under extreme conditions.

3. **Facilitates Compliance:**
   - UL certification aligns with local and international safety codes, making it easier for manufacturers to meet regulatory requirements.

4. **Boosts Market Confidence:**
   - Customers and end-users trust UL-certified products, enhancing brand reputation.

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4. Example Application of UL-Certified Cables

Scenario:
An industrial facility requires cables that can handle harsh environments and EMI-sensitive applications.

Solution:
- **QMTT2** cables are used for general wiring in office areas.
- **QMTM2** shielded cables handle data and communication lines to prevent signal interference.
- **AATJ2** armored cables protect power transmission lines in high-stress areas like workshops.
- **TEPZ2** high-temperature cables are installed near heat-generating equipment.

Results:
- The facility achieves operational safety and compliance with UL standards.

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Why This Step is Critical

1. **Reduces Risk:**
   - Ensures cables perform safely under expected and unexpected conditions.

2. **Supports Regulatory Compliance:**
   - UL certification satisfies electrical codes and regulations globally.

3. **Protects Assets:**
   - High-quality cables reduce the likelihood of equipment damage or operational disruptions.

4. **Builds Trust:**
   - UL certification assures customers of product quality and safety.