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Metal-case LED scrubber light safety

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Metal-case LED scrubber light safety

Postby SantaMonica » Mon 10 Sep, 2018 7:31 am

With the increased usage of natural algal filtration such as algae scrubbers, comes the increased usage of illumination to make the photosynthetic filtering process occur. However a certain type of 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. 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.

The following posts are one person's professional opinion on the safety of these algae scrubber lights. You should consult your own professional advice and opinion from an independent electrical engineer, electronics engineer, electrician, or safety technician.
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Re: Metal-case LED scrubber light safety

Postby SantaMonica » Thu 13 Sep, 2018 8:00 am

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. See photos:

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Re: Metal-case LED scrubber light safety

Postby SantaMonica » Sun 16 Sep, 2018 4:40 pm

I was 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. There is a side-by-side test of LED vs CFL that I did in 2011 on youtube.

The LED lights at first were expensive and cost $150 for one set shipped from China. But the pink “plant grow” colors worked well, and the heat was less. The lifespan was also longer, and it was not fragile to ship to customers. So I started using them on the first waterfall ATS algae scrubbers, which I 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 me. 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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Re: Metal-case LED scrubber light safety

Postby SantaMonica » Mon 24 Sep, 2018 12:05 pm

Having invented the waterfall scrubber design in 2008 (water flowing down a screen), I'm 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. I don’t use that waterfall design anymore, even though I invented it. Nor those lights. Here’s why, with a focus on the 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.
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Re: Metal-case LED scrubber light safety

Postby SantaMonica » Mon 15 Oct, 2018 1:08 pm

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:

Image Image

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:

https://www.youtube.com/watch?v=vbt2ojkXPuo
https://www.youtube.com/watch?v=1Pubk8Ets2I
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