For low-voltage electrical accessories, what are the common applications of porcelain components? (Consider domestic-grade parts such as lamp holders, switch blocks, and protective insulating pieces.)

Introduction:
Porcelain is a ceramic with high dielectric strength, heat resistance, and dimensional stability. The question checks knowledge of typical low-voltage applications where porcelain's insulating properties are advantageous.

Given Data / Assumptions:

• Context: domestic or low-voltage installations.
• Required properties: insulation, heat resistance, non-combustibility.
• Typical parts: switch blocks, insulating tubes/bushings, lamp holders.

Concept / Approach:
Electrical porcelain provides electrical isolation and mechanical support. In low-voltage fittings, it prevents arcing and charring at contact points exposed to heat and small sparks.

Step-by-Step Solution:

Verification / Alternative check:
Standards and catalogs for wiring accessories list porcelain variants for lamp holders and certain switch/fuse bases where thermal performance and safety are critical.

Why Other Options Are Wrong:

• Switch blocks only: ignores other common porcelain parts.
• Insulating tubes only: incomplete; does not reflect full range.
• Lamp sockets only: incomplete; omits switch and tube applications.

Common Pitfalls:
Confusing porcelain with bakelite or modern thermosets; while plastics are common today, porcelain remains a suitable choice where heat and flame resistance are prioritized.

Final Answer:
Switch blocks, insulating tubes, and lamp sockets (all of these)