NPT Cable Glands — NPT Thread Cable Gland Manufacturer
NPT Cable Glands — Factory-Direct Supply, CE & RoHS Certified
If your electrical enclosure, junction box, or conduit system uses NPT (National Pipe Taper) threaded entries — the North American pipe thread standard — you need cable glands built specifically to that specification. Standard metric or PG cable glands will not fit, will not seal correctly, and will not maintain your IP rating.
At Difvan, we manufacture a complete range of NPT cable glands in brass, stainless steel, and nylon — covering thread sizes from 3/8″ NPT through 1-1/2″ NPT, with multiple cable entry ranges for each size. We supply directly from our factory in Yueqing, China, to distributors, electrical contractors, panel builders, and OEM clients across North America, the Middle East, and beyond.
Whether you need 500 pieces of 1/2″ NPT brass cable glands for a panel assembly project, or a full range of NPT type cable glands for ongoing distribution, we offer factory-direct pricing, CE and RoHS certification, and full documentation to support your procurement and compliance needs.
What Is NPT in a Cable Gland?
NPT stands for National Pipe Taper — an American standard thread form defined under ANSI/ASME B1.20.1. In a cable gland, the NPT thread is the external thread on the gland body that screws into the threaded knockout hole of an enclosure or conduit fitting.
What makes NPT threads distinct from metric (M-thread) or PG threads is their tapered profile. NPT threads are slightly wider at the base and narrower at the tip, which means as you tighten the gland into the enclosure, the threads compress together and form a mechanical seal. This taper-seal design is why NPT thread cable glands are widely used in American-specification industrial enclosures, where a thread-tight fit — often supplemented with PTFE tape or pipe sealant — is the standard installation method.
NPT thread sizes are expressed in inches (3/8″, 1/2″, 3/4″, 1″) and relate to the nominal pipe size — not the actual outer diameter of the thread. For example, a 1/2″ NPT cable gland has an actual thread outer diameter of approximately 21.3 mm, not 12.7 mm (half an inch). This is a common source of confusion for buyers new to NPT specifications.
The thread pitch for 1/2″ NPT is 14 threads per inch (TPI), often written as 1/2-14 NPT. For 3/4″ NPT it is 14 TPI, and for 1″ NPT it is 11.5 TPI. These specifications are fixed under the ANSI standard and do not vary between manufacturers.
Our NPT Cable Gland Range
We manufacture NPT cable glands across multiple material and configuration options to meet the requirements of different industries, environments, and project specifications.
Nickel-plated brass glands for general use, offering corrosion resistance and IP65 sealing. Commonly used in panels, enclosures, and machinery. Sizes from 3/8″ to 1-1/2″.
Designed for harsh environments like marine and chemical industries. SS-316 provides strong resistance to corrosion and chemicals. Same size range as brass.
NPT Cable Gland with Strain Relief
Features a clamping system for secure cable grip and sealing. Ideal for vibration or movement applications. Available in brass and SS-316.
Provides IP68 protection with dual sealing. Suitable for underground, wet, or high-moisture environments.
Lightweight, corrosion-proof option for non-metal applications. Made from PA66, available in 1/2″ and 3/4″.
NPT Cable Gland Size Chart
The following size chart shows our full NPT cable gland range with dimensional data for each thread size and cable range variant. Dimensions H (body height), G (thread length), L (total installed length), and spanner size are all in millimetres. This data is based on our standard production sizes — custom dimensions available on request for OEM orders.
Thread Size | Cable Range (mm) | H (mm) | G (mm) | L (mm) | Spanner Size (mm) | Material | IP Rating |
|---|---|---|---|---|---|---|---|
NPT 3/8″ | 4 – 8 | 26 | 15 | 19 | 17 | Brass / SS-316 | IP65 |
NPT 3/8″ | 2 – 6 | 26 | 15 | 19 | 17 | Brass / SS-316 | IP65 |
NPT 1/2″ | 6 – 12 | 30 | 13 | 24 | 21.2 | Brass / SS-316 | IP65 |
NPT 1/2″ | 5 – 9 | 30 | 13 | 24 | 21.2 | Brass / SS-316 | IP65 |
NPT 3/4″ | 13 – 18 | 37 | 15 | 33 | 26.2 | Brass / SS-316 | IP65 |
NPT 3/4″ | 9 – 16 | 37 | 15 | 33 | 26.2 | Brass / SS-316 | IP65 |
NPT 1″ | 18 – 25 | 40 | 16 | 41 | 33.3 | Brass / SS-316 | IP65 |
NPT 1″ | 13 – 20 | 40 | 16 | 41 | 33.3 | Brass / SS-316 | IP65 |
NPT 1-1/4″ | 18 – 25 | 40 | 18 | 46/42 | 42 | Brass / SS-316 | IP65 |
NPT 1-1/4″ | 13 – 20 | 40 | 18 | 46/42 | 42 | Brass / SS-316 | IP65 |
NPT 1-1/2″ | 22 – 32 | 48 | 15 | 52/53 | 48 | Brass / SS-316 | IP65 |
NPT 1-1/2″ | 20 – 26 | 48 | 15 | 52/53 | 48 | Brass / SS-316 | IP65 |
Note on L (total length): For NPT 1-1/4″ and 1-1/2″ sizes, two L values are given (e.g., 46/42 or 52/53) corresponding to the two cable range variants. Spanner size indicates the minimum jaw width required for installation. Always select the cable range variant closest to your actual cable outer diameter for optimum seal performance.
All sizes above are available in both brass and SS-316 stainless steel. Nylon NPT cable glands are available for 1/2″ and 3/4″ NPT sizes. If your cable diameter falls between two available ranges, always choose the variant with the smaller maximum rather than the larger minimum for a tighter, more reliable seal.
Material Options for NPT Cable Glands
Selecting the right material for your NPT cable gland is as important as selecting the correct thread size. The three materials we manufacture are suited to distinct environments and applications:
Material | Key Properties | Best For |
|---|---|---|
Brass (Nickel Plated) | Good corrosion resistance, high mechanical strength, cost-effective, RoHS compliant | Industrial panels, HVAC, machinery, control enclosures |
SS-316 Stainless | Excellent corrosion + chloride resistance, 2% Mo content, high-temperature rated | Marine, offshore, food processing, chemical plants, outdoor/coastal |
Nylon (PA66) | Lightweight, non-conductive, chemical resistant, no galvanic corrosion | Chemical environments, telecom, instrumentation, light-duty installations |
NPT vs Metric vs PG Thread Cable Glands — Full Comparison
One of the most common questions from buyers is: can I use an NPT cable gland instead of a metric one, or vice versa? The short answer is no — these thread types are not interchangeable. Here is a full comparison to help you specify correctly:
Feature | NPT Thread | Metric (M-Thread) | PG Thread |
|---|---|---|---|
Standard | ANSI/ASME B1.20.1 | ISO 68-1 / DIN 40430 | DIN 40430 / IEC 62444 |
Common Regions | USA, Canada, Mexico, Japan | Europe, Asia, Global | Europe, Global (older) |
Thread Form | Tapered (seals on thread) | Straight (seals on seal ring) | Straight (seals on seal ring) |
Sealing Method | Thread taper + sealant | Rubber seal + locknut | Rubber seal + locknut |
Size Notation | 3/8″, 1/2″, 3/4″, 1″ | M12, M16, M20, M25 | PG7, PG9, PG11, PG16 |
Typical Application | American-spec enclosures | European / Asian panels | Older European panels |
Interchangeable? | No — requires NPT enclosure | No — requires M-thread hole | No — requires PG hole |
Difvan Supply | Yes — full range | Yes — full range | Yes — full range |
Key takeaway: If your enclosure is American-made or follows ANSI standards, you need NPT cable glands. If it follows European or IEC standards, you need metric or PG cable glands. Always check your enclosure’s knockout thread specification before ordering. If you are unsure, contact us with the enclosure model and we can advise.
Applications — Where Are NPT Cable Glands Used?
NPT cable glands are the standard cable entry component wherever North American electrical codes and enclosure standards apply. Key applications include:
Industrial Control Panels and Electrical Enclosures
The most common application. Control panels, motor control centres (MCCs), junction boxes, and switchgear built to NEMA or UL standards use NPT threaded knockouts as standard. Our brass NPT cable glands are the direct-fit solution for these installations.
Oil, Gas, and Petrochemical
Refineries, offshore platforms, pipelines, and petrochemical processing facilities — particularly in North America and the Middle East — specify NPT thread throughout. Our SS-316 NPT cable glands are widely used in these hazardous and corrosive environments.
Marine and Offshore Installations
Many American-specification vessels and offshore structures use NPT threaded penetrations for cable management. Our SS-316 NPT cable glands with IP68 double compression sealing are suitable for continuous saltwater exposure and ATEX zone assessments.
Food and Beverage Processing
USDA and FDA-regulated food processing facilities in North America commonly specify NPT thread entries in stainless steel enclosures. Our SS-316 NPT cable glands with smooth, cleanable surfaces meet hygiene requirements for these environments.
Outdoor and Renewable Energy Infrastructure
Solar farms, wind turbine nacelles, and outdoor electrical enclosures in North America use NPT thread entries. Our IP65 brass and IP68 stainless NPT cable glands provide durable, weather-resistant cable management for years of outdoor service.
HVAC and Building Automation
Commercial building systems — HVAC controllers, BMS panels, fire alarm systems, and building automation enclosures — frequently use 1/2″ and 3/4″ NPT knockouts for wiring. Our standard brass NPT cable glands are a cost-effective fit for these applications.
NPT Cable Gland Installation Guide
Correct installation is essential to maintain the IP rating and mechanical performance of your NPT cable gland. Follow these steps for a reliable, code-compliant installation:
- Verify thread size — check your enclosure’s NPT knockout size (3/8″, 1/2″, 3/4″, 1″ etc.) before selecting your cable gland.
- Select correct cable range — measure your cable outer diameter and choose the NPT gland variant whose range includes your cable OD. For optimum seal, the cable OD should be in the middle third of the gland’s range.
- Disassemble the gland — unscrew the clamping nut from the gland body and slide both components and the rubber seal off the cable.
- Apply PTFE tape or pipe sealant — wrap 2–3 layers of PTFE tape clockwise around the NPT threads on the gland body, or apply pipe thread sealant compound. This is required because NPT threads seal on the taper — unlike metric glands which seal on a rubber gasket.
- Thread gland body into enclosure — insert the threaded body into the knockout and tighten by hand first, then use a spanner. Tighten to 2–3 turns past hand-tight — do not overtighten as this can crack brass glands or deform NPT threads.
- Feed cable — feed the cable through the gland body from inside the enclosure.
- Assemble and tighten — slide the seal and clamping nut over the cable. Tighten the clamping nut onto the gland body until the seal is visibly compressed around the cable jacket. Do not overtighten — the seal should grip firmly without distorting.
- Verify installation — check for uniform seal compression around the cable. For IP68 applications, a water ingress test per IEC 60529 is recommended before final sign-off.
Order NPT Cable Glands Direct from Our Factory
We are a manufacturer — not a trading company or intermediary. Difvan Electric Co., Ltd. has manufactured cable management components from our facility in Yueqing, Zhejiang, China since 1997. When you source NPT cable glands from Difvan, you are buying directly from the production source — which means factory pricing, full control over specification, and no supply chain surprises.
- Factory-direct pricing — no distributor markup, competitive landed cost for North American projects
- Full NPT size range in stock — 3/8″ to 1-1/2″ NPT, multiple cable ranges per size
- Both brass and SS-316 stainless steel available for all NPT sizes
- Custom configurations — thread length, cable entry, flange size, surface finish
- OEM and private label manufacturing available
- Bulk orders supported with dedicated project coordination
- CE, RoHS, IEC-certified supply with complete documentation packs
- Export experience: USA, Canada, Middle East, Europe, Australia, Southeast Asia and 50+ countries
- Samples available prior to bulk order commitment
We currently supply NPT cable glands to panel builders, electrical distributors, and EPC contractors across North America and the Middle East. If you are looking for a reliable, certified, cost-competitive source for NPT type cable glands — whether for a one-off project or ongoing distribution stock — we would like to hear from you.
Request a Quote — NPT Cable Glands
Tell us: NPT size, cable range, material (brass / SS-316 / nylon), quantity, and any certification requirements.
Frequently Asked Questions — NPT Cable Glands
Q1: What is NPT in a cable gland?
NPT stands for National Pipe Taper — an American standard thread form defined under ANSI/ASME B1.20.1. In cable glands, NPT refers to the thread type on the body of the gland that screws into the knockout or threaded entry hole of an electrical enclosure. Unlike metric or PG threads, NPT threads are tapered — meaning the thread diameter increases slightly along the length, creating a tight mechanical seal when fully tightened. NPT cable glands are the standard in North America and are also widely used in Japan and parts of Latin America.
Q2: What is the difference between NPT and metric cable glands?
Q3: What sizes of NPT cable glands do you manufacture?
We manufacture NPT cable glands from 3/8″ NPT through to 1-1/2″ NPT, covering cable diameters from 2 mm up to 32 mm. Each NPT thread size is available in two or more cable range variants to match different cable outer diameters. Please refer to the size chart on this page for full dimensions (H, G, L, and spanner size). Custom thread lengths and larger NPT sizes are available on request for OEM and bulk orders.
Q4: What materials are your NPT cable glands available in?
Q5: How do I install an NPT cable gland?
Q6: Are your NPT cable glands CE and RoHS certified?
Q7: Can I order NPT cable glands in bulk direct from your factory in China?
Yes — we are a direct manufacturer, not a trading company. Our factory is located in Yueqing, Zhejiang, China, and we supply NPT cable glands in bulk to distributors, EPC contractors, and OEM clients across North America, Europe, the Middle East, and beyond. We offer competitive factory pricing, flexible MOQ, custom configurations, and full documentation. Contact us with your NPT size, cable range, material, quantity, and any certification requirements.
Contact Difvan Directly
Response within 24 hours. Factory direct — no middlemen.
No.1 HongQi Road, Xinguang Industrial Zone,
Liushi, Yueqing, Wenzhou, Zhejiang, China 325603
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