White Paper | Extreme Temperatures

CABLE CONSTRUCTION: WHEN TO CONSIDER SHIELDING

SILICONE CABLES Silicone cables are suitable for applications involving high temperature, high voltage and a need for flexible wiring. They are also resistant to UV radiation, hydrolysis, oils, chemicals and plant and animal fats. For these reasons, they are commonly employed in metal processing applications, as well as in the industrial, automotive and automation industries because of their superior chemical resistance properties. ÖLFLEX ® HEAT silicone models 180 MS, 180 SiHF and 180 H05SS-F EWKF boast a temperature range of -50 to +180°C and are able to handle rapid heat increases. For these reasons, they are recommended for use in foundries, steel mills, glass factories and commercial baking equipment. These cables are also highly flexible, each featuring an unshielded minimum bend radius of 4x their diameter. LAPP offers four ÖLFLEX ® HEAT silicone models for the North American market: • 180 MS. A high temperature cable with a UV-resistant, halogen-free jacket and North American approvals. It is also available in a shielded version and overall tinned copper braid, which is recommended when electrical interference needs to be suppressed. • 180 SiHF. A halogen-free, high temperature cable that integrates fine stranding for improved flexibility. • 180 H05SS-F EWKF. A high temperature, tear-resistant control cable with approval. It is designed for applications where high temperatures and mechanical abuse can cause other cables to deteriorate. • 180 SiF A. A halogen-free and flame retardant single-core cable with North American approvals. The ÖLFLEX ® HEAT 180 MS and 125 MC cables, made from silicone and cross-linked polyolefins, respectively, integrate a tight weave of multi-strand, soft drawn tinned copper wire—an ideal shielding material for short-run cables. These braid shields provide superior structural integrity while maintaining good flexibility, and minimize low frequency interference. Both ÖLFLEX ® HEAT cables provide braid coverage of 85 percent. Although generally, the higher the braid coverage the more effective the shield, the trade-off between cost and flexibility of the cable design and braid coverage must be considered.

Shielding options can provide cables with EMC protection in the harshest industrial environments. A shield’s effectiveness is determined by its ability to maintain signal integrity in a noisy environment, such as a factory floor or other area containing a high concentration of electrical or communication equipment. Shielding, although not directly related to high heat, takes on importance when designing for thermal environments because a jacket’s material will affect the overall flexibility of the cable—a functional balancing act ÖLFLEX ® HEAT products have achieved.

The conductor material is also an important factor. For higher temperatures, a coated conductor is necessary in order to protect the bare copper effectively against corrosion. Tinned copper conductors should be used within a cable with a jacket made of silicone or cross-linked polyolefin–e.g., for 10 AWG in free air, ambient temperature of 30°C: 90°C rated conductor: 55 amperes versus 150°C rated conductor: 80 amperes (according to NEC tables 310.15). With the most advanced cable technology, the additional thermal performance won’t affect the electrical properties of the cable at all, and any effects on mechanical properties will be minor or even advantageous. Compared to traditional PVC cables, the silicone and cross-linked polyolefin cables will exhibit: • Equivalent flexibility—though polyolefin cables are slightly stiffer than silicone or PVC cables

• Improved wear resistance (for cross-linked polyolefin)

• Improved chemical resistance

• Equivalent flame performance

• Halogen-free construction

The only downside of cables designed for temperature extremes is that they are more costly than a commodity control cable, usually by 250% or so. However, the silicone and polyolefin cables are typically 65% less than a fluoropolymer speciality cable.

LAPP 29 Hanover Road, Florham Park, NJ 07932 T. 800 774 3539

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