In electrical transformers,  particularly in power and distribution models, where clamping bolts and screws keep the core and windings securely in place,  as well as in pipeline flanges and other critical applications, it is essential that bolts are properly insulated from live parts.

This ensures electrical safety, prevents galvanic corrosion, and guarantees the long-term reliability of the equipment. Lasting performance often starts from attention to detail and from reliable protection.

BoltShield™ Tubes, made of Mylar A polyester, Nomex, or a Nomex/Mylar combination, provide superior protection compared to common silicone sleeves. They ensure excellent cathodic protection, prevent bolt corrosion, improve system performance, and significantly extend the service life of your equipment.

Why Politubes Insulating Tubes?

They deliver a safe, reliable, and high-performance solution with distinctive technical advantages:

• Excellent cathodic protection against galvanic corrosion
• Fully customizable to customer specifications
• High performance with tight tolerances and compact dimensions
• Secure clamping and hermetic sealing
• Mechanical rigidity & dimensional stability
• Thermal resistance up to 180°C and 200°C in extreme cases
• Strong chemical resistance to solvents & aggressive acids
• High durability (tear & puncture resistance)
• Resistance to vibrations and high-frequency mechanical stress

Customizable dimensions available:

• Inner diameters from 1.8 mm to 64 mm
• Wall thicknesses from 0.050 mm to 0.800 mm
• Lengths from 8 mm to 6,000 mm

Dimensions can be customized according to customer specifications and application requirements.

The Mylar + Nomex tube acts as both a dielectric and thermal insulator, protecting clamping bolts from discharges, leakage currents, and potential electrical failures.

As a result, transformer reliability and long-term insulation integrity are greatly enhanced.

Nomex® and Mylar® are registered trademarks of DuPont.