Lapp SKINTOP Series 25 Cable Gland

Coax Cable Feed-Through Gland for N and PL Connectors This coax cable feed-through solution is made for a very practical problem: getting a coax cable into an outdoor enclosure without cutting the cable, removing the connector, or adding an unnecessary RF transition. Instead of using a panel-mounted RF connector, the complete coax cable can be passed through the enclosure wall, including many common N-type or PL/SO-239 style connector assemblies. The cable entry is then sealed using a high-quality industrial cable gland together with M&P Silicone-Seal-L cold-shrink silicone sealing tube. Practical idea: keep the coax continuous, avoid extra connector losses, avoid extra RF discontinuities, and still make a clean, weather-resistant cable entry into your antenna box, filter box, preamp enclosure, relay box, or outdoor RF cabinet. Related RF.Guru products and accessories: M&P Silicone-Seal-L cold-shrink coax sealing tube RF.Guru coax, connectors, adapters, and sealing accessories Coaxial sealing products for outdoor RF installations Why Use a Feed-Through Gland Instead of a Panel Connector? A panel-mounted N, BNC, or SO-239 connector is often convenient, but it also adds another RF joint, another place for water ingress, and another point that can loosen, corrode, or introduce mismatch over time. This feed-through method lets the coax cable remain electrically continuous. The shield, dielectric, and center conductor are not interrupted. For receive antennas, remote filters, active antenna boxes, relay boxes, and outdoor RF distribution systems, that can be the cleaner and more reliable mechanical solution. RF note: this is not a bulkhead RF connector. It is a mechanical cable entry. The coax passes through the wall as one continuous cable, so the RF path is not changed by the enclosure wall itself. That makes it especially useful where reliability and weather sealing matter more than having a removable RF connector on the outside of the box. Designed for Pre-Terminated Coax The main advantage is that many coax cables can be installed after the RF connector has already been fitted. That is useful when using factory-made coax assemblies, crimped N connectors, PL-259 connectors, or cables where you do not want to redo the connector after routing it into the enclosure. After the cable is passed through the gland, the sealing area can be finished with M&P Silicone-Seal-L. The silicone tube collapses around the cable and connector area without flame or heat, creating a tight protective sleeve around the entry zone. Typical Applications Outdoor antenna feed boxes Remote antenna switch enclosures Receive antenna preamp or limiter boxes Filter and choke enclosures SDR or receiver distribution boxes Temporary field boxes where the coax must remain connectorized Outdoor cabinets where condensation and splash protection matter Technical Overview Item Typical specification Gland type Industrial metric cable gland, nickel-plated brass type Typical gland size M40 x 1.5 Typical clamping range 19–28 mm Thread length Approx. 9 mm Typical wrench size 45 mm Seal accessory M&P Silicone-Seal-L cold-shrink silicone tubular gasket M&P Silicone-Seal-L length Approx. 14.5 cm Typical cable compatibility Common 10.3 mm and 12.7 mm coax cable classes, depending on connector and final assembly Installation method Pass the connectorized coax through the gland, tighten mechanically, then cold-shrink the silicone seal around the cable/connector entry area Final weather resistance depends on the enclosure wall, hole quality, gland installation, cable diameter, compression, torque, and the quality of the silicone sealing step. Always install with a proper gasket surface and strain relief where needed. Installation Concept The gland is installed in the enclosure wall using a correctly sized round hole. The coax cable, including the connector, is then fed through the gland into the enclosure. Once the cable position is correct, the gland is tightened to grip and support the cable. The M&P Silicone-Seal-L is then positioned over the critical entry area and collapsed by pulling out the inner support strip. The silicone sleeve shrinks around the cable and connector zone, producing a tight, flexible seal without needing heat, flame, tape, or messy self-amalgamating layers. Why Silicone Cold-Shrink Works Well Here Cold-shrink silicone is useful because it remains elastic and keeps pressure on the cable over time. Unlike ordinary tape, it does not rely on adhesive layers alone. It also avoids the risk of heating or damaging coax insulation, connector plating, or nearby plastic enclosure parts. For outdoor RF installations, this is especially useful around vertical cable entries, exposed antenna boxes, or field installations where wind, rain, condensation, and temperature cycling are part of normal life. Important Limitations This product is a mechanical feed-through and sealing solution, not a lightning protector. It does not replace proper grounding, bonding, surge protection, or strain relief. Connector dimensions vary, so always verify the largest outside diameter of your connector assembly before installation. The final seal is only as good as the enclosure wall, drilled hole, gasket surface, and installation method. For permanent outdoor use, route the coax with a drip loop whenever possible. Best practice: do not let the gland carry the full weight of a hanging coax cable. Use a proper cable support or strain relief nearby, especially with heavier coax such as Messi & Paoloni, Ecoflex, Aircell, RG-213 class cable, or similar outdoor feed lines. Who Is This For? This solution is for builders who want a clean and robust cable entry into an RF box without creating another RF connector interface on the outside wall of the enclosure. It is especially useful for amateur radio, receive antenna systems, field stations, repeater accessories, remote switching boxes, and outdoor RF experiments. It is also useful when the connector has already been professionally installed and you simply do not want to cut it off again just to pass the cable through a box wall. Mini-FAQ Can I pass a coax cable with an N or PL connector through it? In many practical cases, yes. The exact answer depends on the outside diameter of the connector body and the gland size used. Always check the largest connector diameter before drilling the enclosure. Does this replace a bulkhead RF connector? No. This is a mechanical feed-through. The coax remains continuous through the box wall. Is this better than tape? For many outdoor installations, yes. Cold-shrink silicone keeps elastic pressure around the cable and connector area and does not require flame or heat. Is it waterproof? The gland and silicone seal can create a very robust weather-resistant entry, but the final result depends on correct installation, enclosure wall quality, gasket compression, cable diameter, and strain relief. Can I use it for receive antenna boxes? Yes. It is very suitable for RX antenna boxes, preamp boxes, filters, switching boxes, and other outdoor RF enclosures where a continuous coax feed-through is preferred. Interested in more technical content? Subscribe to our updates for deep-dive RF articles and lab notes. Questions or experiences to share? Feel free to contact RF.Guru for practical RF installation advice. Written by Joeri Van Dooren, ON6URE – RF engineer, antenna designer, and founder of RF.Guru, specializing in high-performance HF/VHF antennas and RF components.