What Are Connectors? An Admin Buyer's Guide to LAPP Twisted Pair Cable and Cable Glands

If you're buying industrial cable for a new machine or facility upgrade, LAPP's UNITRONIC twisted pair cable paired with a SKINTOP cable gland should be on your short list. Not because the brand is perfect for everything—no supplier is—but because LAPP is unusually clear about what each product can and cannot do. As an administrator who handles roughly $150,000 in MRO purchases a year, that clarity is worth more than any price advantage. Here's why.

The best cable supplier isn't the one with the most options—it's the one that tells you which option actually fits your machine.

I'm not an engineer. I'm the person who processes the purchase orders and lives with the consequences when a part fails. I process 60-80 orders for cable and related components every year, so I've seen patterns. Take it from someone who learned this the hard way: when I took over purchasing in 2020, I thought I just needed the cheapest price and a fast lead time. It took about 60 orders and two costly failures to understand that an honest engineering partner beats a cheap quote every time. In our 2024 vendor consolidation project, I had to standardize parts for 400 employees across three locations. We cut our cable vendors from six to two. LAPP stayed.

One of those failures still stings. We ordered generic cable for a wire-harness application based only on the gauge size. The cable wasn't rated for flexing; it cracked inside a cable carrier and shut down a line for six hours. Total cost including downtime: $4,300. The upside was a 15% price saving. The risk was an unverifiable spec. The cost analysis said the savings weren't worth it. Now I verify the full datasheet before placing any order.

That experience taught me to ask three questions before any cable purchase: what is the application, what is the environment, and what certifications must the final product meet? It sounds simple, but when you're in a hurry, these are the first questions you skip.

What Are Connectors, Exactly?

If you've ever googled 'what are connectors', you're not alone. In industrial equipment, a connector is any device that joins two electrical circuits together. A phone jack is a connector. So are USB ports, M12 connectors, and RJ45 jacks. A cable gland—like LAPP's SKINTOP—is also a connector, but it does something very specific: it secures the cable where it enters a panel or motor and seals the opening. Getting this wrong can void your IP rating and let moisture into control cabinets. That's why I typically check connector specifications more carefully than almost anything else.

Connectors also carry ratings you should never ignore: current, voltage, and environmental protection. A cheap connector might mate mechanically, but if it doesn't have an IP67 rating, you can't use it in a wash-down area. LAPP's catalogue makes those ratings visible on every product page, which saves me from hunting through PDFs. Another thing I look for is how a supplier organizes that information. If I can't find the datasheet in three clicks, that's a problem. LAPP's product pages have a clear link to the technical data, and the data itself includes drawings. For a non-engineer, that's a godsend.

Twisted Pair Cable: More Than Just Wires

Twisted pair cable is the backbone of industrial networks and, believe it or not, still a lot of phone systems. The twists in the pairs cancel electromagnetic interference, so signals stay clean inside a cabinet packed with variable frequency drives. LAPP's UNITRONIC series is engineered for that environment. Depending on the product line, you can get fixed installation cables or flexible cables rated for millions of bending cycles. Their datasheets list bending radius, temperature range, and abrasion resistance—exactly the information a buyer needs to make a confident decision.

According to LAPP's technical documentation (lappusa.com), UNITRONIC cables are designed to meet industrial Ethernet standards like PROFINET and EtherNet/IP. That means you can pick a cable and connector combination already validated for the application. The spec sheet is pretty detailed when you take the time to read it.

Here's a personal example. In a rush order last year, we needed replacement cable for a sensor network. Our usual vendor had a six-week lead time, so I considered a generic option. But the spec sheet didn't list flex cycles, and the jacket material was vague—a red flag. I called LAPP's phone support, described the environment, and they gave me a part number that worked. If you're near De Soto, KS, by the way, their phone support is a practical resource. I've used it to confirm a cable gland size for a local OEM, and they picked up fast.

Keep in mind that twisted pair isn't just for Ethernet. Even today, many office phone systems run on two-pair or four-pair cable. In an industrial plant, standard phone wiring can be exposed to vibration, oil, or heat. That's when you choose a UNITRONIC cable with a heavy jacket instead of a standard plenum-rated cable. The cost difference is small compared to replacing a voice line every year.

Some UNITRONIC cables are designed for use in energy chains and robotic applications, with a special braided shield and a PUR jacket that resists oil. I can't always tell from the description alone, so I call. In fact, I have a standing rule: before ordering a replacement cable, I call the support line and read them the old cable's printing. That usually gets me the right match.

Cable Glands: Small Part, Big Consequences

A LAPP cable gland—the SKINTOP series—is a workhorse in this category, available in dozens of sizes and materials. It might look like a simple plastic or metal nut, but it has one job: hold the cable firmly and maintain the enclosure's seal. The most common mistake I see is ordering a gland with the correct thread size but the wrong clamping range. If the cable is slightly thinner than the gland's range, you get a loose fit and lose the seal. If it's thicker, you damage the cable when you tighten the gland.

We didn't have a formal verification process for this after switching suppliers. It cost us a two-day delay when a machine panel arrived with mismatched glands. The third time that kind of thing happened, I finally created a checklist: thread size, clamping range, IP rating, material. Since then, no mismatches. LAPP's website makes this easier by grouping glands by thread size and clamping range. More than once I've found the exact part using their catalogue, then verified by phone.

Check the gland's thread standard—metric, NPT, or PG. Mixing them up is a classic mistake. In our plant, we have both metric and NPT panels because of different machine origins. I keep a magnetized chart on the wall to double-check. LAPP's gland naming convention is fairly logical once you learn the system, but don't guess.

For wash-down areas or outdoor installations, a nickel-plated brass gland is usually the better choice than nylon. Nylon is fine for clean, dry environments. LAPP offers both, and the price difference is modest. But the failure cost of replacing a corroded gland can be high. This is one of those cases where a short phone call can save a lot of grief.

When LAPP Isn't the Answer

Let me be honest: LAPP is not the right choice for every project. If you're doing a one-off prototype with no certification requirements and budget is absolutely critical, a cheaper cable might be fine. If you need highly custom materials or an exotic connector assembly, a specialized fabricator may serve you better. I learned this when a vendor offered to supply a custom cable assembly with custom branding. LAPP didn't do that, and they referred us to a local shop. The local shop did a great job, and we kept buying standard parts from LAPP. A truly professional supplier will tell you when to look elsewhere. In my experience, LAPP does that. To me, that honesty is a sign of expertise.

Bottom Line

For industrial cable, connectors, and glands, the real value isn't just the part—it's the certainty. Knowing the part will do the job, will fit, and will last. That certainty comes from dealing with a specialist who respects their own boundaries. In my opinion, LAPP qualifies. Start with their twisted pair cable and SKINTOP glands, but only after you've read the datasheet. If you're still asking 'what are connectors', just remember they are the physical links that keep your factory talking, your phones ringing, and your equipment running. Choosing the right one is worth the extra five minutes. When you're planning your next cable buy, don't focus on the lowest quote. Focus on the likelihood that the component will still be working next year. That's the measure that actually hits your budget.