Why Flaw Detection Is Critical in Wire Production

Perfection is not just preferred in a wire manufacturing environment, it’s expected. From Romex wire that powers our homes to superconducting strands that drive medical innovation and high-energy research, the margin for error has all but disappeared. While a defect-free product is the goal, real-world manufacturing comes with real-world challenges. 

Defects happen.

The question isn’t if flaws will occur, but when—and more importantly, how early you’ll catch them. 

The High Cost of Missed Defects 

While a microscopic inclusion or a hairline conductor break might sound insignificant, the ripple effect can be massive. 

Take Romex building wire, for example. It accounts for an estimated 35% of total copper wire production, translating to 500,000–600,000 tons per year. Even assuming a low defect rate of just 0.1%–0.5%, that’s 500 to 3,000 tons of scrap wire annually. 

When each defective ton costs around $12,000, the result is staggering. An estimated $5.5 million to $330 million in material losses, and that’s before factoring in warranty claims, labor, rework, or brand damage. 

Common Types of Manufacturing Defects in Wire & Cable 

In wire and cable production, defects don’t just come in one form, and not all of them can be spotted with the naked eye. While some issues may appear on the surface, others remain hidden inside the conductor or insulation until it’s too late. Each type of defect—whether physical, electrical, or dimensional—can lead to performance degradation, costly rework, or even safety-critical failures in the field. Here's a breakdown of the most common defect categories and why they matter. 

Surface Defects: Scratches, laps, seams 

Typically caused by worn dies, damaged tooling, or inadequate lubrication. Even small imperfections can act as stress risers, reduce fatigue life, and compromise bonding or coating processes downstream. 

Internal Defects: Inclusions, voids, porosity 

Often invisible from the outside, these flaws stem from impurities, poor solidification, or inconsistent material flow. Under tension or vibration, they can lead to cracking, conductor failure, or degraded performance over time. 

Electrical Defects: Broken or missing conductors 

Especially problematic in pre-jacketed products like Romex, these issues often go undetected until post-installation testing, leading to costly rework, tear-outs, and schedule delays. 

Dimensional & Mechanical Variations: Out-of-round shapes, excessive work hardening, and grain structure anomalies 

These variations can cause poor fit, inconsistent electrical performance, or brittle failure during bending, pulling, or terminal crimping.

Real-World Consequences 

Let’s say a reel of Romex has a broken conductor hidden beneath the insulation. It passes visual inspection and is installed behind walls in a new home. Only during final electrical testing is the fault discovered. By then, walls are sealed, outlets are in place, and hours of labor have already been spent. 

At that point, it’s not just a $4 defect. It is a $12,000 repair job and a lost customer.

In high-volume or high-performance applications, even a small defect can affect miles of product length before detection. Missed flaws can lead to: 

• Field failures 
• Safety risks
• Recalls and warranty claims
• Production downtime 
• Scrap costs and material waste

Flaw Detection as a Process Partner

Historically, many manufacturers relied on spark testing (which checks insulation only), destructive sampling, or visual inspection. While these methods have value, they’re increasingly insufficient for modern wire quality requirements.

Non-destructive testing (NDT) methods like eddy current, ultrasonic, and vision inspection systems offer a better way forward. These technologies can: 

• Detect flaws inside insulation and jackets 
• Identify small inclusions or breaks before final spooling 
• Integrate with production lines for real-time rejection or alerts 
• Reduce scrap and prevent field failures

The best flaw detection systems don’t just help you pass inspection; they help you produce better wire from the start.

Real-Time Detection for Real-World Risk 

As demand for high-quality, cost-efficient wire continues to rise, the stakes are only getting higher. For manufacturers, the ability to detect smaller flaws earlier in the process is becoming a competitive differentiator. 

Defects happen. What you do about them defines your success. Prioritizing advanced, inline flaw detection can mean the difference between a rejected spool and a recalled product, between a satisfied client and a damaged reputation. 

At FOERSTER, we’ve spent decades advancing non-destructive testing technologies to support manufacturers.

What You Can Do Next 

Advanced flaw detection doesn’t require a full system overhaul to make a difference. Small, strategic steps can lead to significant gains in quality, efficiency, and confidence. 

Here are six actions you can take today to tighten your process:

1. Set Up for Early Detection: Review where inspection happens on your line. If you're catching defects after value has been added—like post-packaging or jacketing—consider moving detection upstream, before spooling or finishing. 
2. Identify Gaps in Coverage: Confirm what your current NDT systems can and cannot detect. Are you inclusions, broken strands or other internal flaws? You may need multiple detection methods to ensure full coverage. 
3. Connect Detection to Action: Are your inspection systems integrated with your PLC or controls? If not, set up auto-stop or reject triggers so the line responds the moment a flaw is detected. 
4. Log Your Flaws: Start tracking defect data. Record details like timestamp, flaw type, and product ID to begin identifying patterns and root causes. 
5. Train Your Operators: Create a simple SOP that outlines what to do when the system flags a flaw. Then hold a quick team walkthrough to ensure everyone knows the steps and why they matter. 
6. Maintain What You Have: Inspection equipment needs attention, too. Set a routine to clean, inspect, and calibrate your systems, and log verification dates to ensure ongoing accuracy and consistency.