Red Seal Electrician Practice
Wiring and componentsQuestion 194 of 1506

Why are twist-on connectors seldom used on solid wire thicker than #10 AWG?

  1. The connector would overheat at once
  2. The connector could never be taken off again
  3. The shell is rated for under 50 V only
  4. The wire is too stiff to join well
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Correct answer: The wire is too stiff to join well

Thick solid wire is too stiff to hold well in a twist-on connector. Set-screw, clamp or crimp connectors are used instead.

Source: Electrical Fundamentals Competency (Industry Training Authority of BC), 9.3: Solderless connectors

Practice wiring and components

Questions last reviewed: 18 October 2026