Porcelain vs. Polykeram: Which Dielectric Material Offers Greater Reliability for Today’s Grid?
As utilities and OEMs grapple with aging infrastructure and rising demand on the electrical grid, the materials used in critical components—like bushings and insulators—play a pivotal role in performance and reliability. Traditionally, porcelain has been the default choice for high-voltage dielectric applications. But as technology and manufacturing capabilities evolve, advanced composite materials like Polykeram have emerged as more robust, cost-effective, and future-ready alternatives.
In this post, we compare porcelain and Polykeram across key performance categories—thermal, mechanical, and dielectric—so engineers and procurement teams can make informed decisions when specifying components for their systems.
Why Material Choice Matters in High-Voltage Applications
Dielectric components like bushings, arc chutes, and insulators serve as both structural and electrical barriers. They must maintain stability under thermal cycling, mechanical stress, and high-voltage electric fields—often simultaneously.
A failure in any of these components can result in equipment downtime, safety hazards, or even catastrophic failures. That’s why choosing the right material is more than a design preference—it's a strategic decision that impacts the longevity, reliability, and total cost of ownership of critical infrastructure.
Performance Comparison: Porcelain vs. Polykeram
1️⃣ Thermal Properties
Porcelain: Offers decent thermal resistance but is prone to cracking under rapid temperature shifts due to its brittleness and relatively low thermal shock tolerance. This makes it susceptible to failure in high-fluctuation environments.
Polykeram: Engineered for superior thermal shock resistance and stability. It can withstand rapid temperature changes without compromising structural integrity, making it ideal for modern switchgear and outdoor applications with variable conditions.
Advantage: Polykeram
Polykeram’s enhanced thermal shock resistance significantly reduces the risk of fracture and failure under load or environmental stress.
2️⃣ Mechanical Strength & Durability
Porcelain: While strong in compression, porcelain is brittle and can crack under mechanical shock or vibration—common during installation, maintenance, or extreme weather.
Polykeram: Offers a unique balance of high compressive strength and impact resistance. Its composite nature allows it to absorb mechanical energy without cracking, increasing safety and service life.
Advantage: Polykeram
With higher impact resistance and mechanical resilience, Polykeram outperforms porcelain in dynamic environments and harsh field conditions.
3️⃣ Dielectric Strength
Porcelain: Provides reliable dielectric performance but is limited in shape complexity, which can affect creepage distance and stress distribution in custom designs.
Polykeram: Maintains high dielectric strength even under contaminated or wet conditions. Its moldability allows for optimized geometries that reduce electrical stress and improve insulation performance.
Advantage: Polykeram
Not only does it meet or exceed the dielectric performance of porcelain, but its design flexibility improves insulation efficiency and safety margins.
4️⃣ Design Flexibility and Customization
One of Polykeram’s most notable advantages is its moldability. Unlike porcelain, which is limited to traditional manufacturing methods and standard forms, Polykeram can be precisely molded to meet custom specifications—without sacrificing strength or dielectric performance.
This allows for:
Complex geometries
Integrated mounting features
Optimized creepage and clearance distances
For OEMs and utilities seeking engineered-to-order components that fit into compact or retrofit designs, Polykeram opens up possibilities that porcelain simply can’t match.
5️⃣ Total Cost of Ownership
While porcelain may offer a lower initial material cost, it often comes with:
Higher shipping weight
Longer lead times (especially when sourced offshore)
Greater risk of breakage during transit or installation
Limited design flexibility requiring costly workarounds
Polykeram, by contrast, delivers:
Faster lead times with U.S.-based manufacturing
High durability, resulting in fewer replacements
Design efficiencies that reduce integration costs
Advantage: Polykeram
Lower lifecycle cost, faster delivery, and fewer field failures make Polykeram the smarter investment long-term.
Why PBI Uses Polykeram
At Piedmont Bushing & Insulators (PBI), we’ve engineered Polykeram as a high-performance alternative to porcelain, purpose-built for the challenges of today’s electrical systems. Our clients—ranging from major utilities to leading OEMs—count on Polykeram to deliver consistent performance in the most demanding applications.
Our Polykeram-based products are designed, molded, and manufactured right here in the USA.
When evaluating dielectric materials for today’s grid, Polykeram stands out as a more robust, adaptable, and cost-effective alternative to porcelain. For utilities and OEMs prioritizing reliability, flexibility, and long-term value, the choice is clear.