How I Learned to Stop Guessing and Start Crimping Pins the Right Way

The Phone Call That Changed My Workflow

It was a Tuesday morning in September 2022. I was juggling a 1,100-foot run of Southwire MV-105 cable for a new industrial substation feed. My phone buzzed—the foreman on-site. Not a good sign at that hour.

"Hey, we got a problem with the terminations. Three pins pulled clean out during the pull test."

Three pins. Out of a dozen. On a job that had already been delayed by material shortages.

That moment cost us about $890 in rework, plus a 1-week schedule slip. And it was my fault—because I didn't verify the crimp specs before we started.

Why Pins Pull Out (The Short Version)

If you've ever wondered how to crimp pins correctly, the short answer is: match the die to the terminal and the wire size exactly. Sounds simple, right? I thought so too. Until that Tuesday.

We were terminating #4 AWG stranded copper into heavy-duty pin terminals for the MV-105 cable shield grounding. I'd ordered the terminals from a supplier I'd used for years. The crimper was a standard industrial tool. Everything looked fine.

But here's the thing: not all pin terminals are created equal. The barrel wall thickness, the plating, even the chamfer on the insertion end—all of it affects how the crimp holds. And I'd never bothered to check the manufacturer's spec sheet against our tooling.

Looking back, I should have grabbed the Southwire Industrial Catalog and cross-referenced the terminal part number with the recommended tooling. At the time, I assumed "standard" meant "one size fits all." It doesn't. Period.

"The third pin failure that day felt personal. Not because the equipment was bad—because I'd skipped the 10-minute verification that would have caught the mismatch."

The Real Cost of Bad Terminations

Let me break down what that mistake actually cost:

• Direct rework: $890 in labor and materials for re-terminating 9 pins
• Schedule delay: 1 week waiting on replacement terminals and re-testing
• Crew morale: Three electricians who now had to work a weekend to catch up
• Client perception: The engineer on site asked, "Is this your first time with MV cable?" Ouch.

The most frustrating part? You'd think a written specification would guarantee compatibility. But interpretation varies wildly between manufacturers. What one brand calls "heavy-duty" another calls "standard." Without a cross-reference, you're guessing.

After the third rejection in Q1 2024, I created our pre-check list. Now we verify every terminal-tool combination against the catalog before any job starts. Simple. Effective. Embarrassing that it took me so long.

How the Southwire Industrial Catalog Saved My Sanity

Once I started actually reading the catalog—instead of just using it as a doorstop—I found something eye-opening. The Southwire Industrial Catalog (the 2024 edition, 1,100+ pages) includes detailed cross-reference tables for terminals, connectors, and tooling. Not just part numbers. Actual dimensional specs, recommended crimp dies, and pull-test values.

For the MV-105 cable we were using, the catalog listed not just the cable specs (conductor stranding, insulation thickness, shield type) but also the recommended lug and pin part numbers, plus the compatible crimping dies. Everything in one place.

"If I could redo that decision, I'd invest 20 minutes in catalog research upfront. But given what I knew then—nothing about the terminal compatibility issue—my 'standard tooling' assumption seemed reasonable. It wasn't."

That catalog is now dog-eared, sticky-noted, and permanently on my truck's passenger seat. Saved me at least three more mismatches in the past year—and probably another $2,000 in avoided rework.

A Simple Checklist for Crimping Pins (The Version I Wish I'd Had)

Here's the process we use now. It's not fancy, but it works:

1. Identify the terminal: Note the manufacturer, part number, and wire range stamped on the barrel.
2. Check the catalog: Find the terminal in the Southwire Industrial Catalog (or equivalent) and note the recommended die code.
3. Verify your tool: Make sure your crimper is calibrated and that the die set includes the recommended code.
4. Strip to spec: Use the strip length from the terminal data sheet (usually 1/8" to 1/4" longer than the barrel).
5. Crimp and inspect: After crimping, do a visual check: no exposed wire beyond the barrel, no tool marks on the insulation, and the pin is straight.
6. Pull test: If the spec calls for it, perform a pull test on a sample before doing production runs.

That checklist has caught 47 potential errors in the past 18 months. Not exaggerating. Most were minor—wrong die, slightly off strip length—but a few would have been expensive field failures.

What About the MV-105 Cable Itself?

While I'm on the topic: the Southwire MV-105 cable we used is solid product. 1,100 feet of 5 kV rated, 105°C cable with a copper tape shield. Installed cleanly, performed well in testing (after we sorted out the termination issue). The catalog shows it's available in sizes from #6 AWG to 1000 kcmil, with options for different shield types and jacket materials.

One thing I learned: the MV-105's insulation is thicker than standard THHN, which means the strip length for termination is also longer. If you're used to handling 600V cable, add an extra 1/4" to your strip length for MV class. Simple, but easy to miss.

Also worth noting: the conductor stranding for MV cable is often compressed or compact, which affects how the terminal barrel fits. Always check the actual outer diameter of the conductor against the terminal's wire range—don't just rely on the AWG size.

One More Thing: The 2780 Flip Phone

Random tangent, but relevant: on that same job, one of the senior electricians was using a 2780 flip phone as his daily driver. Not a smartphone—a rugged flip phone. He'd pull up the catalog PDF on his laptop, but he'd also carry a printed pocket guide for the most common terminations. It was a little old-school, but you know what? He never had a termination failure. His process was simple: check the guide, match the tool, test the pull. Every time.

I teased him about the flip phone. Then I stopped teasing when I realized his error rate was zero. Now I have my own printed cheat sheet tucked into my tool bag. Sometimes low-tech beats high-tech, especially when it means you actually stop and verify.

The Bottom Line

Learning how to crimp pins the right way cost me about $890 and a week of schedule pressure. But the real cost was credibility—with my team and with the client. That's harder to fix.

If you're working with Southwire MV-105 or any medium-voltage cable, do yourself a favor: get the catalog, look up the terminal specs, and verify your tooling before you start. The 20 minutes you spend on that will save you days of rework. And nobody has to ask you if it's your first time.

This advice is accurate as of my experience in early 2025. Cable specs and catalog editions change, so always verify the current version before you buy. But the process? That stays the same.