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Why LED Underground Light rated IP67 is still with water or moisture inside?
Latest company news about Why LED Underground Light rated IP67 is still with water or moisture inside?

Why the underground lamp with a rated IP67 waterproof level is still leaking?

Why LED Underground Light rated IP67 still with water or moisture inside?


Many of us may wonder that the rated IP67 outdoor underground lights are with water or moisture infiltrating into the internal of the lighting fixture, even though these IP67 LED in-ground luminaires are with IP test reports issued by the Third-party certification bodies which prove these luminaires are passed IP67 tested and IP67 waterproof level. And some of these lights are world well-known international brands which are still leaks or with moisture Attached to the inner of glass cover of underground lights.


Why the underground lights with a rated IP67 waterproof level is still infiltrated with water or vapor?


Before having the answer, it is better to understand and learn what IP67 meanings. IP67 means the ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion). For more information about ingress protection, please view this link>> What is IP code and IK Code?



The reasons for the water leakage or moisture problem of underground lights are main 4 aspects:

1. Unreasonable design

2. Defects in materials

3. Defects in workmanship

4. Improper installation and operation



1. Unreasonable Design

For example, some outdoor underground lamps are sealed with glue to prevent the water from seeping in. These lamps sealed with glue meet the waterproof IP grade indeed when they finished and tested in the factory, or even still working excellent in Third-party certification bodies or lab.


However, the glue will start to get age and turn yellow after about a period of time (around 6 months) of use in an outdoor harsh environment, and the vapor or water will infiltrate to the inner of lamp housing. Therefore, glue sealing waterproofing is unreliable or not enough, the structural waterproofing for outdoor lighting is the kingly way for underground lights, or it is better adopts both structural waterproofing and glue sealing waterproofing technology, especially for IP68 LED underwater lights.


The front cover of some underground lights ere not be pressed firmly or properply, and the manufacturer did not fix the front cover and housing firmly by enough screws. It should be known that LED buried lights are often in an environment immersed by water, and if the front cover is not fixed on lamp body tightly and properly, it is easy to lead to the water or vapor seep into the internal of the underground lighting fixtures via the gaps.

poor design and quality lighting fixtures.jpg


There are only 2 or 3 screws for the front cover for such a large size lamp, and the distance between the screws is far. Do you think it is pressed and fixed tightly?


If the cover of the lamp is not pressed and fixed firmly, there may be gaps, and it is hard to be waterproof even if it is filled and sealed with glue.


some LED inground lights.jpg



The lamp of an international brand in the picture below has no glue sealing inside. Let's check how many screws are used on it? 10 pcs screws.

international well-known brand LED linear inground light.jpg


Several of the lamps mentioned above are not easy to pass the IP67 test. And even if it passes the IP67 grade test, it does not mean there will be no risk of water leakage. Structural design defects in lamps can also lead to water leakage.


LED inground lamp


Some manufacturers perform a soak-in water test for their underground lamps under certain temperature conditions, BUT there is a risk of failure if the test time is too short (such as 5~6 hours) and considered their lamps passed the IP67 testing. But the fact is, the environment of outdoor lamps is complex in the actual working process than the simple testing.


When the fixture is turned on or working under the scorching sun, the inside temperature will increase as the operating time goes. Conversely when the lamp stops working or when it is raining or snow, the temperature will slowly drop. This phenomenon will cause “The Siphon effect”. Thermal expansion and contraction make the inside and outside air pressure differences. The vapor will infiltrate to the housing through the wire entry as soon as the internal air pressure is smaller than the external.


This is caused by the unreasonable structure design of the lamps or improper operation for the connection for the lamp, which leads to the substandard durability of the lamps.




2. Defects in materials


Defects in the material of the luminaire may cause the luminaire to leak.


This is related to the key waterproof materials of the lamps, such as, waterproof nuts, sealants, silicon rings, etc., which often perform well when they are first installed, but their durability is not enough after a long time. The Poor quality silicone rings will get age in two months. And the outdoor underground light is often exposed to the sun, the ring will crack and water will go into the internal of the housing via the gaps. And lead to premature failure for the outdoor underground light which is not reaching the designed life as expectation.


rubber ring, silicone ring cable gland


Even if the silicone ring is not aged, if the silicone strip is not selected properly, and if the selected silicone ring for underground lamp is not an inorganic material but an organic material, It may be acted and decomposed by mildew which the underground light is result in leaking water.


Therefore, the correct selection and high quality of materials is also very important for outdoor LED underground lights.



3. Defects in workmanship

For example, the front cover or the bottom cover or other cover for the underground light must be very dense and fixed firmly by screws when the lamp is assembled. Each screw has its fixed torque, if screws are driven too tight, the silicone ring will be crushed, if the screws are driven too loose, the silicone ring is not tight enough. That is to say there will be a fixed torque for the screws.

led inground lights BOM sheet

Companies with quality assurance have designed the torque for screws, which can be in place in a good position with just a hit of the electric drill. Other companies without design and conditions to design the torque, just screwed it casually during assembly, it’s hard to avoid water leakage issues.


Well, what if it is a well-known international brand, the lighting design is reasonable, and the materials are good quality, does the IP67 underground lamp will not with the leaking water issue?


The answer is NO!


If the in-ground lamp you use is from a famous supplier or qualified suppliers, but it still gets water leakage, the only possibility is improper installation methods.



4. Improper installation and operation

① Installation ground surface is uneven

The general possibility improper operation is that the surface of ground is not on the same level of the front cover of the underground light. The Install ground is uneven, and there are often pressures from pedestrians or cars. Therefore, the position of the pressed rubber ring will lose its elasticity due to excessive pressure-and then it will lead to the lamp leak water or vapor issue?


flat level mounting ground surface for LED underground lights.jpg


②"Short-term waterproof"

If the drainage is not handled properly, the underground will leak if they are immersed in water for a long time. The IP67 of the recessed underground light represents short-term waterproofing only. For long time waterproof requirements and submersed lamp into water for a long time, this kind of lamp should be IP68 underwater light required.


installation method for LED inground Lights by IP67 connectors and with gravel layer beneath of underground lights

▲ There must be a large layer of space under the lamp for filling with gravel, and there must be a drainage pipe at the bottom so that the water can be drained and avoid the underground lamps soaked in water for a long time.


the thickness of gravel must be more than 25cm



Install Condition and method for IP67 Underground Light

▲ Drain pipe.


If the recessed Underground lights are soaked in water for a long time, the environment of the underground light in this case is worse than in the environment in swimming pool. Because the ground is often cleaned with detergents such as oxalic acid, oxalic acid is corrosive, the underground light will be corroded or damaged by oxalic acid, so water or vapor will probably seep into the housing of the underground lights.


So if the installation ground is on flat level and there are drainage measures, will everything be fine and there will be no water leakage issue? Unfortunately, even if these operations are reaches this level and proper, it is still possible for LED underground lights to fail, or with water infiltrated.


③Power connection for LED underground


Another possible cause of water leakage is the power wiring.


Ordinary wiring with tape is actually not waterproof, because water vapor will enter the interior of the lamp along the gap of the tape wrapped around the wire, forming moisture or water mist inside the lamp.


So the reasonable way should be to use a IP68 connector or waterproof junction box. The junction box is filled with soft silicone glue; this way is helpful for preventing water vapor infiltrate to the housing through the wire entry.


sealing for IP68 connection box


There are also many LED in-ground lights delivered with IP67 waterproof male and female connector, most people take for granted it is waterproof for this kind of connectors, BUT In fact, it is not waterproof (after a long time)!



normal connector for

▲Normal Waterproof male and female plugs


In fact, due to man-made reasons such as the tolerance and poor quality of male and female sockets, water will leak from the gap.


Click here to know How to dispose the outdoor light connector correctly?





Overall, the water leakage problem of the buried LED lamp is either caused by the unqualified quality of the lamp itself, or it is caused by the improper operation on installation.


After find out the reason of underground lights leak problem, you are now able to know how to deal with and avoid the leakage problem of outdoor lighting fixture. COMI Lighting is a professional manufacturer and supplier on outdoor lighting, landscape lighting, and architectural lighting luminaires, such as underground lights, in-ground light, underwater lights, swimming pool lights, step lights, wall washer, landscape lights, garden lights, flood lights and etc. If you need a professional company to help you handle the lighting products, feel free to be invited to be one of our partners and contact us @ or call us 0086 755 2315 8250.

Pub Time : 2022-12-02 16:38:10 >> News list
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