Faulty stripping changes the dielectric strength at a conductor splice.

Outline:

• Opening: set the scene with dielectrical strength and why it matters in splicing

• What dielectric strength means in practical terms

• The big culprit: Faulty stripping — why it changes the dielectric strength at the joint

• Why the other factors matter, but not as dramatically

• How to do stripping right: quick guide, tools, and tips

• Real-world considerations: safety, connectors, and failure modes

• A practical checklist to keep dielectric strength high

• Closing thought: small mistakes, big consequences; the safe path

Let me explain the core idea with a quick image. When you splice a conductor, you’re not just tying two pieces together. You’re also trying to keep electricity from sneaking out of the metal and shoving its way through the insulation. Dielectric strength is the conductor’s ability to resist that sneaky voltage from jumping across the joint. It’s the wall, the shield, the barrier that keeps everything behaving. If that barrier breaks down at the splice, you’ve got arcing, heat, and a potential failure path that can cascade into bigger problems down the line.

What exactly is dielectric strength in this context?

Think of dielectric strength as the insulation’s resilience under high voltage. It’s not just about the material itself (the rubber, plastic, or polymer coating); it’s about how that material is arranged at the join. A clean, well-covered splice keeps moisture out, prevents air gaps, and ensures there’s no exposed metal that voltage can “see” from the outside. In short, the splice has to be as tight and as well-sealed as the rest of the cable. When the insulation around the bare conductor is compromised, you give voltage a shortcut. That shortcut shows up as arcing or partial discharge at the joint. And once arcing begins, heat builds, insulation wears, and the dielectric strength of the joined area drops faster than you’d expect.

So, what can change the dielectric strength at the splice? The big one is A: Faulty stripping.

Let me explain why this one stands out. Stripping is the moment you remove the jacket just enough to make a solid contact, but not so much that you reveal more conductor surface than needed. If you strip too little, you’ll have poor contact. If you strip too much, you expose more copper and more insulation boundaries, creating opportunities for moisture ingress or nicked strands. But the direct impact on dielectric strength isn’t about the contact quality alone; it’s about the coverage once you seal it up. Faulty stripping usually means the insulation around the conductors isn’t prepared for a safe, robust joint. Stripping too aggressively can nick copper fibers, creating micro-shorts or thin spots that act like tiny leaks for current. Stripping unevenly can leave irregular surfaces that trap air or permit moisture to creep in once the joint is sealed. Either way, the dielectric barrier at the joint weakens.

Now, what about the other options? B: Proper insulation. It matters a lot for overall safety, but in terms of the dielectric strength of the joint itself, proper insulation around the wire doesn’t automatically repair a poor joint. If the bare metal is too exposed because of faulty stripping, or if the insulation isn’t settled down neatly around the connector, moisture can invade. The key is that insulation is part of the whole system, but the joint’s voltage resistance hinges most on how well the bare conductor is prepared and how well the joint is sealed.

C: Correct gauge selection. Picking the right wire size is essential for current-carrying capacity and heating. A wire that’s the wrong gauge for the circuit can overheat, which degrades insulation over time and can indirectly compromise dielectric strength. But gauge doesn’t change the immediate dielectric strength at a joint the way faulty stripping does. It’s more about long-term reliability and the ability to carry the expected load without overheating.

D: Excess conductor length. More length may introduce other issues—loose connections, increased exposure to vibration, or more surface area for moisture—but it doesn’t directly erode the dielectric strength of the joint at a single splice in the same way that a bad strip job does. It’s a factor to manage for mechanical and thermal reasons, not the core dielectric claim at the joint.

Here’s the practical takeaway: when you’re splicing, the first thing to guard is how you strip. The right stripping preserves the integrity of the conductor and prepares it for a solid, well-sealed joint. The next steps—proper insulation, correct gauge for the circuit, and reasonable conductor length—support safety and reliability, but their direct impact on dielectric strength at the splice isn’t as decisive as a flawed removal of insulation.

A quick, hands-on guide to doing stripping right

• Use the right tool for the job. A quality wire stripper with clearly marked gauge settings helps you remove the right amount of insulation without nicking the conductor. Brands like Klein Tools, Irwin, and Temple are kept handy on many job sites for exactly this reason.

• Know the strip length. Most splices require stripping back enough insulation to expose a clean conductor length suitable for the connector you’re using. If you’re using a twist-on wire connector, you’ll typically want enough exposed copper for a solid mechanical bite, but not so much that excess conductor stands proud beyond the connector or the insulation puckers around it.

• Inspect for nicks and strands. After stripping, run your fingernail along the copper. If you feel rough edges or small nicks, re-strip carefully. Damaged conductors can become initiation points for arcing under load.

• Twist strands neatly (for stranded wire). A clean twist ensures the strands stay together and make uniform contact with the connector. Loose strands can corrode or arc, weakening dielectric strength at the joint.

• Use reliable connectors and sealing. Crimp connectors with proper tooling, or use high-quality solder-and-seal methods if appropriate for the wire and environment. Then seal with heat-shrink tubing or weatherproof tape if moisture is a concern. Proper sealing is part of keeping dielectric strength intact, especially in damp or outdoor environments.

• Don’t overdo the insulation. After you seal, you still want enough insulation to cover the joint completely but not so much that you create a bulky, stressed area that could crack or trap moisture. A neat, flush fit often performs best.

A few real-world notes that often slip into the shop talk

• Moisture is a stealthy saboteur. In damp basements, outdoor enclosures, or wells where water can pool, the joint faces more aggressive challenges to dielectric strength. That’s why good stripping, plus a careful seal, matters so much in those settings.

• Temperature swings stress insulation. In places with big day–night temperature changes, the expansion and contraction can crack insulation if the joint isn’t prepared well. Again, stripping quality and a solid seal become the first line of defense.

• Mechanical movement matters. If a splice sits in a device that vibrates or experiences movement, the joint needs to stay secure. Faulty stripping can make the joint susceptible to micro-motions that loosen the connection and compromise dielectric strength over time.

• Grounding and bonding influence safety, not just dielectric strength at the joint. Keeping equipment properly grounded reduces the risk of shock and stray currents, which is a good companion to maintaining strong insulation at every splice.

A simple checklist you can use on the job

• Inspect insulation condition before stripping: no cracks, tears, or signs of wear near the splice.

• Strip to the recommended length for your connector, avoiding nicked copper.

• Examine exposed conductor surface for flat nicks or rough edges; re-strip if needed.

• Twist strands neatly, then apply connector with appropriate tooling; ensure a solid mechanical bite.

• Apply appropriate insulation barrier: heat-shrink, moisture-rated tape, or other approved sealant.

• Verify there are no stray strands protruding and that the joint sits flush within its enclosure.

• Do a quick continuity check, but also check for insulation resistance with a low-ohm test if equipment allows. A hidden fault at the joint will often reveal itself in resistance readings later on.

Closing thought: small mistakes can have big consequences

Splicing is one of those moments where precision really pays off. The dielectric strength at the joint isn’t just a theoretical number. It’s a real, lived safety factor that protects people, equipment, and your long-term workflow. Faulty stripping stands out as the factor most capable of changing the joint’s dielectric strength, because it directly affects how the conductor surfaces, insulation, and sealing come together. It’s a reminder that the simplest step—stripping correctly—often has the most significant impact on reliability.

If you’re working through NCCER Electrical Level 2 topics, you’ve got a good chance to master this by practicing careful stripping, using the right tools, and following a disciplined sealing approach. In the end, the goal isn’t just a code-compliant splice; it’s a joint that stands up to moisture, heat, vibration, and time. Think of it as giving your splice a quiet confidence—the kind that means you can sleep better at night knowing that the wall between voltage and the outside world is solid, tidy, and ready for whatever the environment throws at it.

If you’d like, I can tailor a quick hands-on stripping checklist to your specific cable types or the connectors you favor on the job. Simple tweaks, big gains. And yes, the habit of doing it right the first time tends to stick, like a good habit that pays off every shift.