PANDUIT: Electrical Full Line

ELECTRICAL SOLUTIONS B1.100 B2. Cable Accessories C1. Wiring Duct C3. Abrasion Protection C4. Cable Management D1. Terminals D2. Power Connectors E1. Labeling Systems E2. Labels E3. Pre-Printed & Write-On Markers F. Index B3. Stainless Steel Ties C2. Surface Raceway E5. Lockout/ Tagout & Safety Solutions B1. Cable Ties A. System Overview D3. Grounding Connectors E4. Permanent Identification Material Failure Testing Property decay can lead to three different modes of failure: loss of strength, loss of toughness, or change in appearance. The critical mode for any given application would depend upon the application and the requirements it places upon the material itself. Loss of strength is monitored by tensile testing samples of the material before and after it has been weathered. This test will reveal the decreasing strength accompanied by extended weathering. Loss of toughness can be monitored by measuring changes in elongation and impact strength. As ultraviolet light exposure time increases and the material becomes brittle, its elongation and impact strength are greatly reduced. It is important to note that brittle failures can occur even when the tensile strength shows no change. Although change in appearance is normally not a failure mode for cable ties, the plastic does tend to discolor and lose its surface gloss as exposure increases. These changes can be measured by color difference using Adams units, which are similar to National Bureau of Standard units. Panduit has its own weathering test program to determine estimated life of various cable tie materials. This includes examining many previously aged samples obtained throughout the world. In all cases, the amount of property decay increased with increasing exposure to ultraviolet light. The principal signs of degradation were found to be brittleness, cracking, and loss of surface gloss. It was also determined that the time for failure to occur was shorter than indicated from industry tests performed on material samples. This discrepancy is in part due to the fact that cable ties were tested in an end use, stressed condition, while most plastic resin suppliers conduct weathering tests using unstressed test bars. Five cable tie materials have superior ultraviolet light resistance: TEFZEL ■ , HALAR ▲ , Weather Resistant Acetal, Nylon 12 and Stainless Steel. Determining the outdoor life expectancy of any material is difficult since there are other factors, besides ultraviolet light stability, which have to be considered. These factors are listed below and should be considered before specifying a cable tie material. *Based on the assumption of minimum loading, no chemical attack and impact-free conditions. ■ TEFZEL is a registered trademark of E.I. du Pont de Nemours and Company. ▲ HALAR is a registered trademark of Ausimont USA, Inc. Factor Chemicals Bundle diameter Loading Thickness Vibration Degree of exposure Moisture Galvanized metals Effect on Cable Tie Life Applications which have chemicals present can reduce the life of a tie. This is the most detrimental factor to the life of a tie. As the bundle diameter is reduced, the tie has more bending stress. A thick strap on a small bundle diameter has more stress. If the tie is under high loading, this will add additional stress on the tie body. A thinner tie will have a decreased life since surface cracks will penetrate the thickness of the tie faster. Applications with high vibrations will cause impact, which will propagate any surface cracks. No shield or shade, southern exposure, higher altitudes and high temperatures, decrease the life of a cable tie. High humidity plus high temperature can result in degradation due to hydrolysis in nylon. Acid rain and acid moisture acting on galvanized metals release chemicals known to attack Nylon 6.6. Weathering Life Expectancy Material, Color (Part Number Suffix) Polypropylene, Green (109) Nylon 6.6, Natural (No suffix) Flame Retardant Nylon 6.6, Black (60) Flame Retardant Nylon 6.6, Ivory (69) Heat Stabilized Nylon 6.6, Natural (39) PEEK, Polyetheretherketone, Translucent Brown (71) Heat Stabilized Nylon 6.6, Black (30) Weather Resistant Polypropylene, Black (100) Weather Resistant Nylon 6.6, Black (0 and 00) Heat StabilizedWeather Resistant Nylon6.6, Black (300) Weather Resistant Nylon 12, Black (120) TEFZEL ■ , Aqua Blue (76) HALAR ▲ , Maroon (702Y) Weather Resistant Acetal, Black Stainless Steel Years* 1 1 – 2 1 – 2 1 – 2 1 – 2 1 – 2 4 – 5 7 – 9 7 – 9 7 – 9 12 – 15 >15 >15 >20 >30 Weathering (continued) Table A – External Factors That Affect the Life of a Cable Tie