Silicone – still the best material for high voltage connectors

Silicone remains the go-to material for high voltage connectors and cable assemblies. While new plastics give OEM and interconnect designers many options when it comes to connectors and cable assemblies, the properties of silicone make this time-tested material ideal for high voltage and specialty applications.

Silicone is naturally flexible, resistant to heat, moisture, ozone, UV, and most chemicals, does not take a set, can be securely bonded to other materials, and is easy to mold — an ideal material for interconnect use.

Caton has been manufacturing silicone connector and cable assemblies for more than 40 years. High voltage connectors that utilize silicone and silicone-insulated wires perform for decades in the harshest conditions. Caton pairs this venerable rubber material with innovative design to produce standard and custom high-voltage connectors that withstand high voltages, extreme use, and temperature extremes. Many of the company’s military and aerospace interconnects rely upon silicone parts and insulators to withstand the vacuum of space, the jarring forces of use at sea, and the critical demands of the world’s most sensitive test devices.

19-Series high voltage connector
The Caton 19-Series — a high-performance high-voltage connector — features silicone components that can withstand temperatures of -50ºC to 100ºC with no loss of continuity.

The properties of silicone are one key to Caton’s no-corona connector technology. These connectors feature a conical silicone plug that mates to a matching silicone receptacle. Compressing the mating pair using its screw coupler evacuates all air from the mated connection, virtually eliminating the possibility of voltage arcing. The connectors also feature silicone o-rings and other parts that do not take a set, even when compressed and deformed for years at a time. Silicone parts return to their original molded form when connectors are decoupled and pressure is released.

Silicone chemically bonds to itself and can be securely bonded to other materials using the appropriate techniques. Caton uses a variety of methods to ensure that silicone parts bond permanently to metal housings and other connector components. Some connectors, like Caton’s 14-Series, feature a silicone connector body that is bonded directly to the cable to form a continuously insulated part that is more resistant to moisture, vibration, and arcing than non-silicone assemblies.

Overcoming silicone’s few drawbacks is easy and inexpensive. Sharp ends of braided shielding material used to strengthen cables, reduce electrical interference, and improve grounding can abrade silicone and cause punctures in extreme cases. Placing neoprene sleeves between silicone insulation and wire sleeving reduces this likelihood. Protective sleeves can also be used to protect silicone from oils or other harsh chemicals which can penetrate silicone.

Because silicone is easy to pot and mold, it can accommodate a wide range of connector components. Caton manufactures silicone cable assemblies that incorporate its standard connector platforms, third-party connectors, or a combination. Another versatile aspect of silicone is its ability to be impregnated with carbon or other particles to become semiconductive. Semiconductive silicone can be used to reduce electrostatic interference in sensitive applications. Connectors used in semiconductor test devices must provide exceptionally clean and consistent voltage. Even minuscule fluctuations in signal transfer can cause these exceedingly sensitive devices to give false readings. Semiconductive silicone insulation reduces errant voltage and other interference throughout the connector assembly.

The benefits of silicone go beyond its value as a high voltage insulator. Silicone is also a safer choice for certain environments. Fire is a significant risk in enclosed-space applications like vehicles, aircraft, and marine vessels in which personnel may not be able to escape exposure to smoke and chemicals easily. Silicone is naturally heat-resistant and flame retardant. Unlike some plastics, silicone can be formulated and treated to reduce the outgassing of hazardous substances like halogen gas when burned. Caton post-cures silicone components using a specialized heating process to minimize the presence of volatile compounds that could be problematic in sensitive environments and vacuum applications. Heat resistance and flame retardance also make silicone an ideal choice for high-heat applications like ovens, welding automation equipment, and more.

BOY 25EVH liquid silicone machine

Caton’s investment in capital equipment like the BOY 25EVH liquid silicone machine furthers its silicone molding capabilities, increases manufacturing efficiency, and enables a larger volume of silicone cables assemblies for its customers.

Today, Caton uses many materials to manufacture its custom and customizable standard connectors and cable assemblies. The many benefits of silicone mean that this proven compound will always play a role in our product lineup and provide our customers with safe, high-performance connectors and cables that stand the test of time.