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Metric Cable Gland Size Chart: How to Select M Threads by Cable OD
Selecting a metric cable gland is not a matter of choosing the closest thread name. A reliable selection starts with the finished cable outer diameter (OD), then checks the enclosure thread, the gland’s clamping range, and the installation environment. This order helps purchasing teams avoid a common failure: choosing an M thread that fits the panel but leaves the cable near the edge of the seal range. For industrial panels, junction boxes, and equipment housings, the correct relationship between cable OD and the gland insert is what supports a stable, repeatable seal.
This guide uses the nickel-plated brass M-thread cable gland data in the 2026 Hongxiang catalogue. The standard construction listed there includes a nickel-plated brass body, a PA66 nylon claw rated UL94-V2, EPDM or silicone sealing components, and an EPDM or silicone O-ring. The standard type is listed as IP68 at 10 bar, with a working temperature of -40°C to 100°C and short-term exposure to 120°C. Always confirm the exact model and sealing material for the finished application.
Table of Contents
Start with Cable Outer Diameter, Not Conductor Size
The cable gland seals the outside jacket, not the copper conductor cross-section. Two cables with the same conductor count can have different jacket diameters because insulation thickness, shielding, armor, fillers, and jacket material vary. Measure the finished round cable with calipers at the point where it enters the enclosure. Then choose an insert range that contains that measurement with room on both sides. A cable placed near the center of the stated range normally gives the installer more tolerance than a cable positioned exactly at the minimum or maximum limit.
Hongxiang Metric Cable Gland Size Chart
| Metric Thread | Catalogue Cable OD Range | Example Catalogue Code |
|---|---|---|
| M12 × 1.5 | 3–6.5 mm; 4–8 mm | HX-NP.M12 / HX-NP.M12-8 |
| M16 × 1.5 | 3–6 mm; 4–8 mm; 5–10 mm; 6–12 mm | HX-NP.M16 series |
| M20 × 1.5 | 5–10 mm; 6–12 mm; 10–14 mm; 12–16 mm | HX-NP.M20 series |
| M25 × 1.5 | 6–12 mm; 10–14 mm; 12–16 mm; 13–18 mm; 15–22 mm | HX-NP.M25 series |
| M32 × 1.5 | 13–18 mm; 14–20 mm; 15–22 mm; 18–25 mm | HX-NP.M32 series |
| M40 × 1.5 | 18–25 mm; 22–28 mm; 22–30 mm; 25–33 mm | HX-NP.M40 series |
| M50 × 1.5 | 30–35 mm; 32–38 mm; 37–44 mm | HX-NP.M50 series |
| M63 × 1.5 | 32–38 mm; 35–40 mm; 37–44 mm; 42–52 mm | HX-NP.M63 series |
How to Read the Table in a Real Selection
Take M20 as an example. The catalogue lists more than one M20 option: 5–10 mm, 6–12 mm, 10–14 mm, and 12–16 mm. The thread is the same M20 × 1.5, but the sealing insert changes with the cable diameter. A 9 mm cable can use the 5–10 mm or 6–12 mm option; the final decision should take the cable’s roundness, installation tolerance, and the exact product drawing into account. A 13 mm cable should not be forced into a 6–12 mm insert simply because the enclosure already has an M20 opening. It requires the M20 10–14 mm option, provided the thread and panel design are appropriate.
The same principle applies at larger sizes. For M25, Hongxiang lists ranges from 6–12 mm through 15–22 mm. For M40, listed options include 18–25 mm, 22–28 mm, 22–30 mm, and 25–33 mm. These options allow an OEM to match the sealing range to a cable family instead of treating each metric thread as a single fixed cable diameter.
Three Checks Before You Release a Purchase Order
Before finalizing your procurement, perform these three essential technical checks:
- Confirm the finished cable OD and compare it with the stated clamping range. Do not select only by the nominal cable designation.
- Confirm the enclosure thread and thread pitch. For the models listed here, the metric series uses the M thread shown in the table, such as M20 × 1.5 or M25 × 1.5.
- Confirm application requirements: sealing material, operating temperature, chemical exposure, panel thickness, locknut requirement, and any project-specific standard.
Frequently Asked Questions
The catalogue lists several possibilities depending on the required enclosure thread. In the standard M series, M20 × 1.5 is available with a 5–10 mm or 6–12 mm range, while M25 × 1.5 is available with 6–12 mm or 10–14 mm options. Select the final model according to the panel thread and the desired position of the cable within the range.
No. M20 identifies the thread size, not one universal cable range. The Hongxiang catalogue shows multiple M20 insert ranges, including 5–10 mm, 6–12 mm, 10–14 mm, and 12–16 mm.
The listed standard construction uses nickel-plated brass for the body, PA66 nylon for the claw, and EPDM or silicone rubber for the sealing components and O-ring. The catalogue lists IP68 at 10 bar and -40°C to 100°C working temperature, with short-term exposure to 120°C.
Conclusion
A metric cable gland is selected by matching the cable OD to a suitable sealing range and then verifying the enclosure thread. Hongxiang’s M-thread nickel-plated brass range covers small cables from 2–5 mm in selected M10 options through large M120 options up to 88–95 mm, with multiple insert ranges for many common threads. Use the table as a technical starting point, then verify the exact product code, drawing, and application conditions before ordering.
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