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Thread: Metal-Case LED Light Safety

  1. #1
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    Metal-Case LED Light Safety



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    Metal-Case LED Light Safety

    With the increased usage of natural algal filtration, comes the increased usage of illumination to make the photosynthetic filtering process occur. However a certain type of metal-case light has come onto the market, and this light needs to be addressed because it is potentially unsafe when used on ATS algae turf scrubbers. We do not use these lights, but unfortunately other people do. If you do not have these lights, then you can decide whether to get them or not. If you already have them, then you can learn how to protect yourself, or to change the lights entirely.

    Over time, the problem of the metal case gets worse, not better. At some point most of the metal cases will reach a critical point due to the corrosive operating environment of sump-mounted waterfall algae scrubbers. Whether this is 6 months or 6 years depends on the light, the scrubber housing, the sump environment, and the usage. The simple solution is to just not use metal-case 240/120 volt lights.

    Even if you have 1, 2 or 6 of these lights, and they've had no problems for 6 months, or a year, or three years, that does not mean that other people should not be informed. Imagine if your car had a defect that only showed up for 1 in 100 people, and you were the one that got injured. Would you want the car company saying "There is no defect. We have a customer that has two of these cars and he's had them for three years; if there were a defect he'd know about it." Of course not. You would want the pertinent information. And as a maker of LED lights, and being an Electrical Engineer, I feel I am qualified to provide this information.

    Several scrubber builders were asked to provide input/articles to be included here; nothing was received. Also I offered to provide free electrical design advice to improve the safety of their scrubbers; all declined.

    The following is one person's professional opinion on the safety of metal case, high voltage, algae scrubber lights. You should consult your own professional advice and opinion from an independent electrical engineer, electronics engineer, electrician, or safety technician before using these lights. Again, we refuse to use them.

    To subscribe to the updates of this safety information, click here (must be logged in), and select "Notification Type" to be "Instant Notification By Email"...

    Last edited by SantaMonica; 2 Weeks Ago at 04:24 AM.

  2. #2
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    The lights are typically used when people build or buy the waterfall scrubber design we invented in the year 2008:

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    The light is a metal-case LED lighting fixture that is bolted on, and is typically made in China and sold online, but it could be made anywhere. It is designed for gardens and patios, with some rain, or for indoor growing areas that get no rain at all:

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  3. #3
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    We at Santa Monica Filtration were the first to test and use these types lights on waterfall scrubbers in the year 2010, as a way of getting away from fluorescent bulbs. Here is a side-by-side test of LED vs CFL in 2011:


    The LED lights at first were expensive and cost $150 for one set shipped from China. But the “plant grow” color worked well, and the heat was less. The lifespan was also longer, and it was not fragile to ship to customers. So we started using them on our first waterfall ATS algae scrubbers, which we invented in the year 2008; here is the acrylic box with a bottom shelf for the lights to set on, and a top shelf above the lights for protection:

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    Currently, all waterfall scrubbers for sale by others use this same open source free-to-copy waterfall scrubber design because it kind of works, and because the design was given away for free by us. It has problems, but again, it’s free to copy. And almost all pre-made scrubber builders also now use those metal-case LED bolt-on lights, mainly because they now cost only $5 including shipping from China. This makes the cost of those pre-made scrubbers artificially low, because they don’t have to make the lights safe (or even test the lights for safety), and this transfers the electrical risk to you, the customer. This typical Ebay listing of 20 lights for $99 even says "U.S. stock" to make it less apparent that they are from China:

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    Last edited by SantaMonica; 1 Week Ago at 11:07 AM.

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    Having invented the waterfall scrubber design in 2008 (water flowing down a screen), we are fairly familiar with how the scrubber works. And how the lights work too. Many people DIY their own scrubbers, and for these people the metal-case LED lights are fine to use as long as safety is observed. This is because DIY people tend to have experience with electricity, water, etc, and they are trusting their own skills to make things safe for themselves. If something goes wrong, only they get hurt. But commercial makers of scrubbers are expected to provide a safe product, because it will be purchased by consumers who are not expected to have experience in electricity. We don’t use that waterfall design anymore, even though we invented it. Nor those lights. Here’s why, with a focus on safety:

    The biggest problem with those lights is the fact that a line voltage of 240/120 volts comes directly into the metal-case light which is a non hermetically sealed compartment; and the light is placed within inches of splashing saltwater and salt-creep that comes out from the top of the scrubber. The scrubber is then placed on top of an open saltwater sump, where there is more splashing and more salt creep. The sump is almost always under a tank, with a simple front cabinet door that lets light out; larger tanks with sumps like these are usually located in a common area of a house such as a living room. Where children play. And it’s commonly known, and almost predictable, that the floor area in front of the sump gets wet, even when the cabinet door stays closed. It does not take much to imagine one’s child opening the cabinet door to see the “pretty pink” light, and then trying to touch it, while standing on a wet floor at the exact moment that that salt creep has shorted the internal 240/120 volts of the light to its metal case. So, the idea of writing this information is to prevent this from happening.
    Last edited by SantaMonica; 1 Week Ago at 11:08 AM.

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    As an electrical engineer (BSEE), people like me are sometimes asked to be expert witnesses in court cases about electrical safety liability. In the USA, electrical safety is tested, and accepted most readily in industry, by Underwriter’s Laboratory (UL). Unfortunately this testing is expensive, and if a Chinese LED light maker pays for the UL certification, the cost of their lights will be much higher (and the certified product will have a “eXXXXXX” number on it). But UL certification shows that a third party has inspected the power supply to be safe, instead of just the maker of the product saying it’s safe. Also unfortunately, none of the Chinese LED lights described above are UL certified, as far as I know. This problem becomes bigger because the metal case of the light (metal is needed to remove heat) is what “protects” the wires and electronics inside. However this metal case in not hermetically sealed (not truly “waterproof”), and indeed because of the $5 cost it is often rushed through assembly where even the rubber seals are incorrectly inserted, or forgotten altogether. Here is an example "waterproof" light from ebay, fresh out of the box; you can see the "waterproof" seal on the 240/120 volt wire is completely not sealed:

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    There have been cases on aquarium forums, and on youtube, where the metal compartment screws have not been tight, or were missing. Ground wires were loose, or just cut off. Internal drivers loose and rattling around. Heat sink compound too thin or missing, causing overheating and melting of wire insulation, and even causing steam from water that was splashed on it. Because of this, it’s my personal opinion that using these metal bolt-on LED lights is potentially unsafe in the saltwater environment of scrubbers which are setting on sumps. Googling “chinese led light danger” finds too many results to read, but here are typical ones:


  6. #6
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    For people not familiar with salt creep (maybe you only have freshwater), it gets into everything. Any crack, surface, or other area inside a sump will eventually get at least a light coating of salt creep, even if the direction of the surface goes upwards. Areas closer to the sump top will get a coating that you can wipe with your fingers, just like dirt on the ground. Areas on the top rim of the sump where scrubbers are placed will get coatings thick enough to require scraping tools. And salt creep is always wet, so yes, it’s very conductive of electricity. It’s the single biggest cause of shorted-out power sockets in sump areas. Any 240/120 volt electrical device in a sump area needs to be hermetically sealed, or else it will eventually get salt creep into it. It might take months, or years, but it will happen. Here are examples:


    And here is a more thorough description of residue build-up, which is similar to salt creep but occurs in freshwater too:



    What does hermetically sealed mean? It means it's air-tight. And if it's air-tight, it's waterproof. It would be difficult to make the metal-case lights air-tight, because you would have to basically weld the case together. The most common way of making electronics air-tight and waterproof is make them a solid component, like we did with our GEM lights. No air space inside at all:


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    All other aquarium sump equipment has the 240/120 volt area hermetically sealed: power heads, heaters, etc. The metal-case LED lights that are being used for algae scrubbers by some people seem to be the only equipment not sealed properly.

  7. #7
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    Related to salt creep, is corrosion creep. Because the metal case of the bolt-on lights is aluminum, it can corrode slowly (even in freshwater) where the seal is located, especially at the top of the light where water splashes onto it. So even a seal that is designed and assembled correctly can be pushed sideways by corrosion creep, and eventually the seal will not be sealed anymore. And if it’s on the top of the light, water can now drain directly down onto the 240/120 volt electronics inside, and you won’t see it because the corrosion is on the inside of the seal area. A stainless steel case would prevent this, but low cost metal-case lights are never stainless. Stainless enclosures are used in underwater 240/120 volt pool lighting, but those lights start at $100 each. Here is a pool accent light with a single 3 watt LED inside, and it is $40; note how much stainless steel is needed to protect it:

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    The best way to slow down corrosion is during disassembly inspection: coat both sides of the metal case (where they touch together) with grease or petroleum jelly, and re-insert the seal, and re-assemble. Ongoing disassembly and inspection every 6 months is advisable. Unfortunately, each month that goes by will allow more salt and corrosion creep to occur, and the seal will only get worse, not better. And, just like the Chinese do, you might actually mess up a seal during re-assembly, which was fine before you took it apart. So be careful.

    Interestingly, most commercial scrubber builders use absolutely no metal in their main boxes which hold the algae growth, because of course the metal would corrode. There are many low cost metal boxes that could be used, which would not crack during shipping like acrylic/perspex does, but builders instead take the time to hand-construct boxes out of acrylic/perspex so that corrosion will not be an issue. So why then do they allow metal on the lights (the most important area for safety) if they know it will corrode?

    The reason again is simple: Cost. Just $5 to $8 each, including shipping from China. But the Chinese know that if someone is injured because of these lights, nobody will be going to China to sue them. So the Chinese have absolutely no need to make things safer. It’s up to the DIY person to check each light (by taking it apart), and it’s up to each commercial scrubber maker to request UL certification, non-metal construction, low voltage operation, and hermetically sealed enclosures. Like we did with our GEM lights.

    It's my opinion that all of the low cost metal-case lights are made in China, even if they have been relabeled to look otherwise. I've spent hundreds of hours trying to find lights (and other parts) in the USA, only to be directed to China every time. The cost of the metal castings for the case alone would be $10 or $20 each, if made in the USA. And the labor to assemble the electronic and other parts would be another $30 at least. So manufacturing in the USA is not an option for these types of lights, and if they say “Made In USA” you should assume this is not true. This was yet another reason for us to abandon these metal lights (and their internal electronics design) and go with our non-metal cast molded low voltage design instead, which we make right here on our desks in Santa Monica, California, USA. But even if the bolt-on metal Chinese lights were made in the USA, and even if they were UL certified, you still have the problem of the electronics enclosure not being hermetically sealed. So if water, or steam, or salt creep gets inside, and you touch the metal case, it’s not going to matter who made it, or who certified it, or what the warranty is. This was the final reason for us separating the power supply away from the light, so that the 240/120 volts would be 2 meters away from the splashing and salt creep:

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