Porcelain is a ceramic made by heating various raw materials in a kiln. During this process the kiln can reach temperatures of up to 1500 degrees Celsius. After baking, a glassy, translucent product is produced yielding high permeability and a white or off white color. Even though this material is known for its strength, it is very brittle. This is the main reason for cracking and breaking under extreme environments or if dropped from any height. Porcelains uses can vary from sculptures or fine china, to dental crowns, to chemical wares used as forms for molten metals. Its high resistance to the passage of electricity makes this material an excellent insulator for the utilities industry. MPS offers porcelain fused cutouts to protect overhead distribution systems.
Polymers are materials whose molecules contain a large number of atoms linked together by covalent bonds. Under the microscope, the chemical makeup is mainly identical units joined together to form a repetitive pattern called a monomer.
Engineering polymers (aka synthetic polymers) are one of the fastest growing materials industries.
The reasons for this include its ease of manufacturing, vast uses, and mechanical properties. Polymers can be broken down into the following categories:
Thermoplastics – Makeup is linear and one dimensional, able to be heated and recycled.
Thermosetting – Makeup is three dimensional, and once set cannot be heated back down without destroying the material.
Elastomer – Makeup is very rubbery and capable of being stretched to more than twice its original form. What makes this type special is that after stretching, it can return to its original shape without any damage to the material.
Polymers are used in everyday items like Lego blocks, copper wiring insulators, and even light bulb covers on street lamps. The great hydrophobic characteristics of polymer materials make it an ideal candidate for the utilities industries to use in high corrosion areas. Unlike porcelain, the polymer doesn’t crack or break when dropped or submitted to extreme temperatures on both ends of the spectrum. MPS offers its fused cutouts in polymer as well and recommends this material for all types of environments. There are other benefits to using polymer over porcelain aside from durability and functionality. The polymer material allows for more flexibility within the design regarding available leakage distances. Where porcelain units may have to have different designs to cover higher leakage requirements, the polymer unit can reach significantly higher values within the same size package. An example would be our new generation polymer cutout design as seen below.
With our new alternating shed profile and electrical grade fiberglass rod core, the new design provides higher leakage distance then all other 15kV designs. A porcelain unit with comparable specs is roughly 2 times heavier than its polymer counterpart. In previous designs for polymer cutouts the end fittings were molded onto the core. This allows for weak points if dropped from high distances or too much torque is applied. The new MPS design now has crimped end fittings creating a much stronger, more mechanically sound product.