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DELIVERING QUALITY SINCE 1952.
Cable Assembly Outer Jacket Performance Functions
02.19.16
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Agenda
Cable Assembly Jacket Purpose Assembly Design Guidelines Types Of Stress Assembly Jackets Need To Address Assembly Jacket Material Selection Guidelines Types Of Jacket Materials Available Assembly Safety Considerations Certification Substitution Chart Summary
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Assembly Outer Jacket Purpose
Protect The Environment – Flammability– Toxic Gasses
Protect The Underlying Cable Core– Drives Jacket Compound Selection
• Often More Critical Than Electrical Requirements– Mechanical Damage– Moisture/Chemical Damage– UV Resistance– Facilitate Installation– Provide Identification and Grouping– Sterilization– Vibration Or Movement– Safety Certifications
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Designing Assemblies WithCorrect Jacket Material
Cables & Cable Assemblies– Often Considered Last During System Design– Cable Assembly Is System Lifeline - When Assembly Fails Entire System Fails
Assemblies Designed Based On Durability/Signal Integrity
Choosing Wrong Cable Jacket Type Has Implications– Shortens Life Of The Assembly– Causes Basic Health And Safety Concerns
Assembly Engineered To Last Life Of Product It Is Attached To– Regardless Of The Installation Environment– Current Needs - Smaller/Lighter Assemblies Costing Less Lasting Longer
Essential To Identify Constraints Affecting Performance– Electrical– Mechanical– Environmental– Application Specific Factors
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Cable AssemblyMechanical Stress
Exposure To Harsh Environments– Unique Conditions With Potential To Compromise Reliability/Performance
• Extreme Temperatures, Chemicals, Abrasion, Extensive Flexing
Mechanical Stress – Assembly Exposed To Movement(Tight Spaces/High Speeds)
– Handheld Devices, Automation, Aerospace Applications, etc.
– Movement Includes Random, Rolling, Torsion Type Motion• Creates Kinetic Energy Causing Damage• Movement Allows Cables To Rub Against Each Other Or Surrounding Hardware, Generating Friction
Resulting In Jacket Abrasion
– Biggest Cause Of Mechanical Stress - When Cable Assembly Is Part Of Equipment Handled By A Person
• Can Kink, Pinch, Crush, Step On, Roll Equipment Over An Assembly
– Harsh Environment Allows Assemblies To Contact Sharp Surfaces • Cuts Cable Jackets, Exposes Assemblies To Severe Abrasion
– Acceleration/Vibration Stress Can Compromise Signal Integrity • Premature Failure
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Cable AssemblyEnvironmental Stress
Environmental Stress – Caused By The Physical Area Where Assembly Is Used And Exposed
– Extreme Temperatures Affect Cable Materials• Low Temperatures Make Them Brittle - High Temperatures Make Them Soft
– Extreme Pressures Impact Cable Assemblies• Vacuum (Very Low Level Of Pressure) Leaches Oils/Additives Out Of Cable Assembly - Contaminating
Surrounding Work Surface
– Hydrostatic Pressure Causes Gases/Liquids To Permeate Assembly Jackets• Gases, Liquids, Cleaning Fluids, Fuels, Lubricants, Chemicals, Steam Destroys Some Cable Assembly
Materials
– Radiation Destroys Jacket Materials - Depending On Type/Dosage Levels
– Mud, Chemicals, Or Metal Chips Can Damage Assembly Jackets
Environmental Stress Can SignificantlyShorten Useful Life
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Cable AssemblyApplication Stress
Application Specific Stress - Constraints Unique To Application – Aerospace – Assemblies Need To Be Lightest/Smallest Possible To Minimize Mass During
Takeoff
– Network Routers - Require Long Assemblies To Transmit Large Quantity Of Information At High Data Rates – Assembly Size/Attenuation Issues
– Public Spaces – Potential Of General Public Contact • Transportation, Automotive Applications, Public Buildings• Need To Observe Safety Issues Such As Flammability, Voltage, And The Use Of Halogens
Assembly Designers Need To Understand That Electrical, Mechanical, And Environmental Performance Is Interwoven
– Each Element Has An Impact On The Others – Designing An Assembly Ensuring Performance In One Area Impacts The Other Areas
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Cable AssemblyJacket Material Selection
Operating/Environmental Issues– Assembly Design Will Address All Of The Factors – Selecting Correct Materials For Assembly Construction– Ensure Sufficient Testing Completed
• Verification Assembly Will Match The Application– Every Assembly Must Match The Installation Environment
• Different Issues In Different Environments - Spacecraft, Aircraft, Cleanroom, Factory Floor, or Datacenter
Choosing Correct Materials For Assembly Jacket Is Crucial– Ensuring Signal Integrity - Insulation/Jacketing Materials With Attributes To Protect Signal
During Transmission– Dielectric Materials Affect Signal Integrity As Well As Robustness Of Assembly– Insulation Material Used Affects Maximum Voltage And Resistance To Abrasion– Jacket Materials Have To Meet/Exceed External Factors
• Temperature, Friction, Liquids, Gases
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Assembly Jacket Materials
Possible Materials Used As Cable Insulations/Jackets Extensive– Many Developed For Specific Applications
• Transportation, Power, Data Transmission, Industrial, Medical, etc.– Some Materials More Appropriate Than Others For Harsh Environments
Polyvinyl Chloride (aka PVC, Vinyl)– Relatively Inexpensive/Easy-To-Use– Used For Commercial, Industrial, Computer, Control Wire, Medical, Food Related
Applications– Versatile And Widely Known/Used Compound– Many Formulations For Many Varying Applications
• Flexibility, Temperature Range– Not Good For Flexibility At Low Temperatures– Corrodes Over Time Under Certain Conditions – Exposure To Oil
• Petroleum Based - Will Begin Dissolving If Coated With Oil– Not UV resistant
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Assembly Jacket Materials
Silicone – Primarily Jacket Insulations/High Voltage Conductor Insulation– Flexible At Low Temperatures– Very Good Radiation Resistance– Very Flexible– Known To Outgas Silicon Oil In Vacuum Applications– More Labor Intensive To Gain Access To Conductors– Cuts Easily– Low Resistance To Oil– Sticky Surface Results In High Co-Efficient Of Friction
Polyurethane – Halogen Free Grades Available– Very Resistant To Cut-Through And Abrasion– Flexible Grades Sticky/Tacky – Resulting In High Co-Efficient Of Friction– Resistant To Solvents, UV Rays, Radiation, Fungus– Does Not Have A Very Broad Temperature Range
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Assembly Jacket Materials
Polyolefin– Appropriate For Primary Insulation - Jackets Tend To Be Stiff Affecting Flexibility – Some Grades Abrasion Resistant – Exhibit Low Co-Efficient Of Friction– Temperature Range/Flame Retardance Limited– Difficult To Bond To (Adhesion)
Fluoropolymers– Able To Withstand Extreme Temperatures - Each Material Has Own Range– Withstands Exposure To Chemicals, Acids, Aggressive Solvents– Naturally Non-Flammable– Liquid/Gas Resistant– UV Resistant– No Out-Gassing – Low Radiation Resistance– Low Abrasion/Cut Through Resistance
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Safety Certification Considerations
Cable/Assembly Jacket Is First Line Of Defense In A Fire– Important Installation Aspect - How Assembly Impacts Those Working Around Or
With It– Need To Consider How Assembly Will Respond In Event Of Fire– First Defense Against A Catastrophe When Fire Breaks Out - Control The Fire And
Stop It From Quickly Spreading– PVC Jackets Burn Very Easily – Fire Can Leap From Room To Room/Floor To Floor By Burning Along The Installed
Assemblies/Cables Local And National Building Codes Often Require Plenum Rated
Cable/Assembly Jacket – Self Extinguishing– Will Not Allow Fire To Burn Along Them
PVC Releases Hazardous Gasses When Burned LSZH Jackets
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Safety Certification Authorities
NEC (National Electric Code)– “Recommended Standard”
• Becomes law when officially adopted by state or local governments• Local inspector has responsibility of enforcing
UL (Underwriters Laboratories)– Safety Consulting and Certification– Tests cables and components to set standards
CSA (Canadian Standards Association)– Develops standards that enhance public safety– Test cables and components to set standards
Regulation Compliance– California Prop 65– RoHS– WEEE– Conflict Minerals
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Cable Certification Summary
Plenum Rated Cables– Complies with NFPA-262 and UL-910. Only cable allowed in spaces defined as air
plenums such as raised flooring systems and air handling ducts. Plenum cables must self-extinguish and not re-ignite
Riser (CMR) Rated Cables– Complies with UL-1666. defined for usage in vertical tray applications such as
cable runs between floors through cable risers or in elevator shafts. These cables must self extinguish
Low Smoke Zero Halogen (LSZH) Rated Cables– Used in shipboard applications and computer networking rooms where toxic or
acidic smoke and fumes can injure people and/or equipment. Examples of halogens include Fluorine, Chlorine, Bromine, and Iodine. These materials when burned produce acidic smoke than can cause harm. These cables will self-extinguish
General Purpose (CM, CMG, CMx) Cable– Complies with UL-1581 testing. They will burn and partially self-extinguish. Not for
use between building floors or in air plenum spaces.
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Cable Substitution Chart
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Cable Jacket Purpose Summary
Protects the Installation Environment Protects The Cable Core Components
– Damage Due to Outside Influence– Ensure Proper Performance
Material Selection Critical To Ensure Operating Conditions Met– All External/Internal Factors Need Consideration
Design Cable Assembly As Early In Development Process As Possible
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Our Products
Battery Packs Flex & Rigid-Flex PCB’s User Interfaces
Fans & Motors Cable Assemblies Printed Circuit Boards
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Design Centers & Technical Support
Battery Pack & Power Management – Denver, CO User Interfaces – Largo, FL Fans & Motors – New Bedford, MA & Wales, UK PCB’s – New Bedford, MA & Shenzhen, China Flex & Rigid Flex – Toronto, Canada Cable Assemblies – Largo, FL
Our Engineering and Design teams are ready to help our customers create world class and cost effective product solutions.
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Q&A
Questions?– Enter any questions you may have
in the Control Panel
– If we don’t have time to get to it, wewill reply via email
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Thank YouCheck out our previous webinars at www.epectec.com.
For more information email [email protected].
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