Electrical porcelain — which preparation method is correctly matched with the voltage class of porcelain insulators? Choose the correct statement.

Introduction / Context:
Porcelain electrical insulators are produced using either wet (plastic) processes or dry pressing, depending on the required geometry, density, and electrical performance. The voltage class often dictates the forming route and firing schedule for optimal dielectric properties and mechanical strength.

Given Data / Assumptions:

• Two broad forming routes: wet (plastic forming, slip casting) and dry pressing.
• Low- vs high-voltage applications require different densities and microstructures.
• Statement matching is about typical practice.

Concept / Approach:
Low-voltage porcelain components (e.g., switches, small insulators) are commonly produced by dry pressing, which yields consistent shapes at high production rates. High-voltage, complex shapes are more often made by wet plastic forming or slip casting to achieve the required density and uniformity with fewer flaws.

Step-by-Step Solution:

Verification / Alternative check:
Industry practice and ceramics texts note dry pressing for small/LV porcelain parts and wet/slip processes for larger/HV insulators.

Why Other Options Are Wrong:

• A: Reverses the typical assignment.
• B: Also reversed; HV usually uses wet/slip processes.
• D: Incorrect since C is correct.

Common Pitfalls:
Assuming one process fits all; geometry and voltage class drive the forming choice.

Final Answer:
Low-voltage porcelain is prepared by dry process