Waterproof End Cap for Tubes

This waterproof end cap for LED tubes, manufactured by professional manufacturer and OEM supplier JE, is made of polycarbonate and comes with a waterproof nut. It is assembled using a glue-applied method, which enables the entire tube to achieve an IP65 protection rating. It is suitable for modern LED plant lighting and other applications requiring waterproof tubes.

Product Features

End Cap Sizes by Tube Type

This is where people get confused. "T8" doesn't tell you the end cap size. You need to match the tube diameter and the pin configuration.

For T8 waterproof end caps, the effective length is usually around 12mm. T12 end caps run a bit longer, sometimes 13.5mm or even 20mm total length depending on the design.

One thing that trips people up: T8 and T5 end caps are not interchangeable. The tube diameter and socket size are completely different. You can't just force a T8 cap onto a T5 tube. There are adapter caps that let you run a T5 tube in a T8 socket, but that's a different product.

Waterproof Nut Sizes: The Part Everyone Forgets

The end cap is only half the waterproofing story. The nut is the other half. And here's the thing—the nut size depends entirely on your cable diameter, not your tube size.

JE's standard waterproof nut sizes are:

● M12 × 1.5 — Fits cable diameter 3–6mm

● M16 × 1.5 (regular) — Fits cable diameter 4–8mm

● M16 × 1.5 (big head) — Fits cable diameter 5–10mm

That's the basic range. Some suppliers also offer PG7 and PG9 variants, which are essentially the same thread sizes but use the PG (Panzergewinde) standard. PG7 corresponds roughly to M12, and PG9 to M16.

The material matters too. Most plastic waterproof nuts are made from PA (nylon) or PP (polypropylene). PA is the better choice—it's tougher, harder, and lasts longer. PP is cheaper but more brittle over time.

If you're not sure which size to pick, measure your cable's outer diameter with calipers. Add a millimeter or two for the seal compression, and pick the nut size that covers that range. Getting the nut too big means the seal won't compress properly. Too small and you can't fit the cable through.

Applications

The obvious answer is "outdoors." But that's not the whole picture.

Plant factories and grow rooms. This is probably the fastest-growing application right now. LED grow lights run 12–18 hours a day in environments with 60–80% relative humidity. Standard G13 end caps will corrode and short out within months. Waterproof T8 end caps with IP65 protection are the standard solution.

Parking garages and underground spaces. These areas are damp, poorly ventilated, and often have water dripping from the ceiling. IP65 or IP67 end caps keep the tubes running without constant maintenance.

Commercial kitchens and food processing. Steam, grease, and daily washdowns. IP65 is the minimum here. Some facilities spec IP69K for high-pressure cleaning.

Agricultural buildings. Poultry houses, dairy barns, and greenhouses all have ammonia and moisture in the air. Ammonia is particularly nasty—it attacks standard plastics and metal contacts. PC end caps with sealed gaskets hold up much better.

Cold storage and freezer rooms. Temperature swings cause condensation. When you open a freezer door, warm humid air rushes in and condenses on every surface, including the inside of your light fixtures. Waterproof end caps with proper seals prevent that moisture from reaching the driver and LEDs.

Outdoor signage and light boxes. If you've ever seen a light box with water stains inside the diffuser, you know what happens when the end cap fails.

A Quick Note on Installation

The end cap itself doesn't do much if you don't install it correctly. Two things matter:

Adhesive. Most waterproof end caps for tubes are designed to be glued onto the tube, not just pushed on. Apply a bead of silicone or the manufacturer's recommended adhesive around the inner rim, press the cap on, and hold it for about 30 seconds. Let it cure for 30 minutes before handling.

Nut torque. Don't overtighten the waterproof nut. The seal needs to compress, not get crushed. Hand-tight plus a quarter turn is usually enough. Overtightening can crack the plastic threads, especially on cheaper nuts.

Product Details

Types of Waterproof End Caps for Tubes:

Not all waterproof end caps are created equal. Here's the breakdown:

Standard sealed end cap (no hole). This one has no opening for wire. It goes on the dead end of the tube where no cable exits. If your tube is single-ended powered, this is what you put on the other side.

Waterproof end cap with nut port. This is the one people usually mean when they say "waterproof end cap." It has a threaded opening where you screw in a waterproof nut. The nut compresses a rubber seal around the cable, creating an IP65 or higher seal.

Integrated end cap with built-in driver space. Some waterproof T8 end caps have room inside for a built-in driver. This eliminates the need for an external driver, which is a huge deal for plant lighting setups where you're trying to keep everything compact.

Locking screw end caps and step end caps. These are more about mechanical retention than waterproofing, but some versions can be paired with sealing gaskets for IP65 protection.

Product Qualification

As a LED Aluminum Profile and LED plastic profile professional manufacturer, here are our main machines:

1. 20 plastic extrusion machines

2. 5 aluminum extrusion machines,

3. A professional integrating sphere to test whether the lamps made by our lamp kit can meet the various indicators required by customers,

4. A professional standard light source testing equipment for testing the light transmittance and other properties of plastic lampshades. 

JE always focus on product qualification from aluminum and plastic raw material to extrusion production line, from samples quality control to mass production control, from strong perfect package to whole-heart service.

Deliver,Shipping And Serving

FAQ

Q1. Can Your products be installed under the cold weather?

Re: Yes, Weather resistance of PC is -40 degree to 120 degree.

Q2. What kinds of LED lighting can use your profiles?

Re: LED cabinet lighting, LED strip lights, T5/T6/T8/T10/T12 tubes, tri-proof tubes and special-shape tubes, etc.

Q3.How many staffs in your factory? Re: 50-80 staffs in production line. 8 staffs in sales team, 10 staffs in R&D.

Q4. How long is your lead time?

Re: For our regular items the lead time is about 3-5 days. For customized items, the lead time is about 25-35 days including tools making time.

Q5. What is your normal processes for regular order?

Re: We are very suggest customer give the forecast for the next three month. This are our normal processes for regular order:

Receiving PO--Sales confirm PI with customer--Receiving 30% payment in advance--Sales assistant proceed production and confirm the exact LT--QC confirm the goods are ready for shipping--Receiving the balance payment--Arranging shipment--after sales service.