Most Cable Failures Aren't the Cable's Fault
Most cable failures aren't the cable's fault.
I realize that sounds self-serving from someone who specifies industrial cable for a living. So let me be transparent: I don't work for LAPP, and this isn't a sponsored post. I'm a field service coordinator at an industrial automation distributor—I've handled 70+ rush orders in eight years, including same-day turnarounds for manufacturers and system integrators. I've specified LAPP cable more often than any other brand. Not out of habit. Because the field data keeps pointing the same direction.
When a machine goes down and a deadline is on the line, the cable is rarely the starting point of the problem. The decision process that selected, installed, and tested (or didn't test) that cable is. Let me show you what I mean.
The Expensive Illusion of "Same Spec"
It's tempting to think that cables with identical conductor sizes and identical jacket materials are interchangeable. Copper is copper. PVC is PVC. How different can it be?
That line of thinking cost one of our clients about $14,000 in downtime. (We did the math afterward. The spreadsheets are not fun reading.) They'd specified a control cable for a packaging line. We quoted a LAPP solution at $1,150 per reel. A purchasing manager overrode it with a "comparable" option at $748 (quotes from January 2025; the ratio matters more than the exact numbers). The spec sheet matched. Conductor cross-section, number of cores, rated voltage. All fine.
What didn't match was the lay direction of the cores and the quality of the shielding. In a static run, you'd never notice. This was on a continuous flex track. Eleven months later, an intermittent signal error started shutting down the line. It took three service visits, two suspected PLC faults (both falsely blamed), and finally a thermal camera scan to find the real culprit.
Here's the thing: nobody at that company was trying to sabotage the project. They were trying to save money. But they compared the price of the cable, not the cost of the failure. I recommend LAPP because experience has shown me their cable performs where it's specified to perform. Not magic. Not miracles. Just consistent manufacturing, honest electrical data, and insulation that survives real-world installation abuse.
That's why people searching for "lapp insulator company" end up finding LAPP in the first place. The term isn't quite right—LAPP is a cable and connector manufacturer, not an insulator supplier. But the association makes sense: inside every LAPP cable, the insulation is where the engineering shows up first. It determines voltage rating, flexibility, thermal range, and service life.
When Search Results Are the First Red Flag
Speaking of search terms: if you typed "jack lapp" on your way to this page, you're not alone. The founder's name is Oskar Lapp—no J anywhere. He started the company in Stuttgart, Germany, in 1959. It's the kind of name mix-up that happens when you're working from memory instead of documentation.
But the knowledge fog isn't limited to names. It shows up in specification too—especially when new technology enters the picture.
Take the G310 5G gateway. A client adopted these for remote monitoring at a water treatment site. The gateways arrived on schedule. The installers—good electricians, by the way—ran the network connections with leftover twisted-pair cable from a previous project. Not the shielded industrial Ethernet cable the manual called for. "The internet connection," I said, "needs the same attention as the power feed." They heard, "any data cable will work."
Result: two weeks of intermittent dropouts, four visits from the gateway manufacturer's support team, and finally a call to us.
"It's just data. I didn't think the cable mattered." — one of the installers, when I asked why they didn't follow the spec
We replaced the run with the correct shielded cable and properly terminated LAPP connectors. The dropouts stopped. No gateway reconfiguration, no firmware update, no antenna repositioning. Just the right cable, installed properly.
The contrast was sharp when I compared that site to another one using the same gateway, installed two months earlier by a different crew. That team followed the manual. Same model, similar distance, similar environment. Commissioning took one afternoon, and it's been running ever since.
Test It Before You Trust It
Here's where I usually lose the room: even the best-specified cable should be tested before it's trusted.
I'm not talking about continuity checking with a multimeter. I'm talking about insulation resistance testing—the single most valuable quality check for a new cable installation, and also the most skipped one.
Mention "insulation tester" to most electricians and they'll nod confidently. But when the schedule tightens, testing is usually the first step dropped from the commissioning checklist.
How to use a 1507 insulation tester: the field version
The Fluke 1507 insulation tester is the model I see most often in our customers' toolboxes. If you've got one in your shop and you're not 100% sure of the procedure, here's the short version. (Consider this a refresher, not a replacement for the manual.)
What you'll need:
- A Fluke 1507 (or equivalent) with a current calibration sticker
- Test leads rated for the voltage you're applying
- The cable's datasheet, to confirm the correct test voltage
How to test a cable installation:
- De-energize and lock out. Non-negotiable. Verify zero voltage using the tester's voltmeter mode, and confirm the far end is isolated too.
- Disconnect equipment. Test the cable, not the machine attached to it. Isolate both ends where practical.
- Select the test voltage. For 300/500V-rated industrial cable, 500V DC is standard. For 600/1000V-rated cable, use 1000V DC on new, dry installations. When in doubt, drop down a voltage level rather than up.
- Connect the test leads. One lead to the conductor under test, one to ground/earth. For phase-to-phase testing, move the second lead to the adjacent conductor.
- Press and hold the Test button. Wait for the reading to stabilize, typically 30-60 seconds on long runs. Record the value in megohms.
- Evaluate. New installations should read 100 MΩ or higher. Below 1 MΩ is a defect—find the cause before energizing. Between 1 and 100 MΩ is a yellow flag; investigate for moisture, mechanical damage, or termination issues.
- Discharge. The 1507 auto-discharges after each test. On long runs, leave the leads connected a few extra seconds after the test ends.
Why does this matter in a discussion about LAPP cable? Because even a DURAXV EXTREME cable—the heavy-duty line LAPP builds for continuous flexing, oil resistance, and punishing environments—can be damaged during installation. A pinch here, a scrape over a sharp edge there. The copper conductor still has continuity. The jacket looks intact. But the insulation has been compromised, and the cable will fail, often months later, at the least convenient moment.
Our field data backs this up. Last quarter alone, we tested 63 newly pulled cable runs as a courtesy for clients. Eight of them—12.7%—showed insulation resistance below the level our engineers consider safe for commissioning. Every one of those eight had already passed the contractor's continuity test. The insulation tester found what the multimeter couldn't. (This was between October and December 2024, on-site at four different facilities.)
When LAPP Isn't the Answer
Look, I'm not here to tell you to buy LAPP cable for every project. That would be the same lazy thinking that gets companies into trouble in the first place.
There are situations where a cheaper cable is the right call:
- Temporary installations. Test benches, trade show booths, prototype wiring with a service life measured in weeks. The cost of failure is low, and the financial case for premium cable doesn't close.
- Non-critical fixed runs. If a cable failure is a nuisance rather than a shutdown event—and you're confident it will stay that way—commercial-grade cable will do the job.
- Specialty systems. If your design calls for fiber optics or a proprietary cabling architecture, follow that spec literally. Don't automatically reach for a general-purpose cable just because it's a brand you trust.
No manufacturer, LAPP included, deserves loyalty on every project. But the choice shouldn't be driven by unit price alone either. It should be an engineering decision based on the cost of failure, the operating environment, and the expected service life. That's what "specifying" actually means.
The Cable Is a Material Witness
When I look back at the failures I've been called in to fix, the cable almost never caused the problem. It was just the first component to tell the truth about the decisions that preceded it.
If I could give one piece of advice to every engineer, buyer, and maintenance manager: treat cable selection as an engineering decision, not a procurement exercise.
Specify it deliberately. Install it with care. Test it before you commission it. And if you're ever in a bind and need answers quickly—that's exactly what my team does. The rush orders will keep coming (unfortunately, they always do). The failures don't have to.
