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Difficulty: HardWire Preparation Tools

While assembling a wiring harness, a technician prepares a 16 AWG stranded copper wire. The technician accidentally places the wire into the 20 AWG notch of a precision wire stripper and closes the handles to strip the insulation. What physical damage occurs to the wire, and what electrical problem does this create in the circuit?

  1. A
    The notch is too large for the wire, compressing the insulation jacket without cutting through to expose the conductor.
  2. The undersized notch severs outer conductor strands, reducing the effective cross-sectional area and causing localized heating under electrical load.Answer
  3. C
    The friction from stripping alters the atomic structure of the PVC jacket, turning the surrounding insulation into a conductive path.
  4. D
    The nicked copper strands form an immediate short circuit within the single wire, dropping circuit resistance to zero.

Answer

The undersized notch severs outer conductor strands, reducing the effective cross-sectional area and causing localized heating under electrical load.
Because American Wire Gauge numbers are inversely proportional to wire diameter, a 20 AWG opening is significantly smaller than a 16 AWG conductor core. When the stripper closes, the blades cut through the insulation and slice into the outer copper strands of the conductor. This reduction in the wire's cross-sectional area increases electrical resistance at that point, which can cause excessive heat dissipation (I2RI^2R losses) and mechanical failure under vibration.

Step-by-Step Solution

1
Analyze the relationship between American Wire Gauge (AWG) numbers and conductor diameters.
A 16 AWG wire has a conductor diameter of approximately 0.0508 inches (1.29 mm), whereas a 20 AWG stripper notch is calibrated for a smaller conductor diameter of approximately 0.0320 inches (0.81 mm).
In the AWG system, higher gauge numbers represent smaller wire diameters.
2
Determine the physical impact of placing a larger conductor into an undersized stripper notch.
The stripping blades cut deeper than the thickness of the insulation jacket, penetrating into the conductor bundle and severing or severely nicking multiple outer copper strands.
The calibrated cutting aperture for 20 AWG is substantially smaller than the overall conductor core of a 16 AWG wire.
3
Evaluate the electrical and mechanical consequences of severed conductor strands.
Conductor resistance is inversely proportional to cross-sectional area (R=ρLAR = \rho \frac{L}{A}). Severing strands reduces AA, thereby increasing localized resistance RR and generating excessive heat (P=I2RP = I^2 R) when normal operating current flows.
Current must crowd through fewer intact strands, leading to thermal stress and mechanical weakness at the stripped section.

Key Concept

AWG Gauge Calibration and Conductor Integrity in Wire Stripping
Estimated Time:1m 30s
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Topics

Wire Preparation Tools

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