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Thread: More safety warnings needed

  1. #1

    Join Date
    Dec 2009
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    Union City, CA, USA
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    More safety warnings needed

    It looks like the trend is a lot more people trying to build ATS systems, which is great.
    Unfortunately, that means more chances of problems, and it also appears to be drawing more people that are less DIY-savvy.

    Basically, I see a lot of designs that seriously scare me. Like chance of death scary.
    I may not be an ATS expert, but I do have 25+ years experience as an electrical engineer. So this is not some alarmist rant.

    There are really 3 issues combining to make a scary situation:
    1) A lot of things can go wrong with a DIY design, such that you could get zapped.
    2) Since a lot of this is done as an experiment, cheap and quick is a very common approach, often equaling unsafe.
    3) Perception of 120V is you get a nasty shock. But add saltwater, and it gets a lot more serious.

    In fact, the recommendation of a "simple bucket ATS" itself might need some rethinking.
    That is the most potentially unsafe design of all.
    Sure, if done carefully and correctly, it could be fine. And yes, even if done wrong, it would take some bad luck to get fried.
    But take some cheap wall-mart lights on an extension cord, throw it together quick, wait a few months for
    some nice salt accumulation and corrosion, get careless when cleaning, and you have one less member on this site.

    I would respectfully ask SM/Worley to please think about putting some note on the dangers and safety prominently on the FAQ page.
    Preferably with its own topic, almost line 1. Yes, there is some good info there, but it is buried, and not well emphasized.
    BTW, with the sale of the SM100, you might want to be worried about personal liability as well.
    Another more controversial concept to reconsider is what types of designs to push for/against.

    ---

    What can go wrong?
    A) Everything will get wet.
    With an ATS, and all that water moving, expect very high humidity, even in an open box. Everything will get condensation.
    So when those lights click on, the bulbs, wires, reflectors, box, everything will probably be quite wet.
    B) Salt creep
    Even dry salt creep conducts. But combine that with condensation, and it means that not only is everything soaking wet,
    it is probably soaking wet with highly conductive salt water.
    C) Dangerous voltages and currents.
    Sure, 120V is dangerous. But some ballasts, especially instant-start types, seriously increase that, to several hundred volts.
    It gets worse: There are capacitors and chokes(inductors) in various ballast types.
    These can keep the power going when you get zapped. So don't expect that GFCI to help.
    D) Dangerous assumptions.
    I bet people think outdoor rated lights are safe. - WRONG.
    Outdoor lights are certainly far better. But most are not waterproof, only water resistant!
    And specifically, they are not airtight against humidity.
    E) Great chance of a current loop.
    So you pick up that nice salt-water wet pipe on your screen in one hand, which is a great ground.
    And you touch a light with your other hand where there is a bit of salt creep to a nice power source.
    You now have a very nice complete electrical circuit, with your torso (heart) in the middle.
    Dead meat, not just a little jolt.
    F) Maintenance and mistakes.
    Sure, you think you sealed that light with silicone. But that degrades, especially under high lighting. And it is easy to miss a small spot.
    Same with sealing your wiring connections.
    And even worse, you are trusting the bulb/ballast manufacturer. Made in china? Never any mistakes there.
    G) Lack of care in the design.
    Did you seal your lighting (bulb + ballast + socket) and ALL your wiring connections?
    Do you have a GFCI?
    Do you have a real earth ground line connected to lights, reflectors, and everything?
    Do you even know of all the places where it could fail? I don't.
    H) A GFCI may not help
    It likely will, and definitely should be included in ALL designs.
    And if it does trip, seriously spend some time figuring out why before turning it back on.
    But they work by detecting and imbalance in current between line and return (hot / neutral).
    So it detects and stops a short between line and earth-ground, not between line and neutral.
    Also, is it away from the humidity? Did you ever test it?


    Key safety checklist:
    1) Include and test GFCI.
    2) Use quality outdoor lights, preferably truly sealed.
    3) Use silicone to seal lights, wiring, everything.
    4) Always turn off lights when cleaning or even touching ATS.
    5) Make sure there is an earth ground on all metal components.
    6) Never have lighting inside an enclosed container with the running water
    7) Consider one of those titanium earth-ground aquarium probes.

    Hopefully others can contribute safety ideas as well.

  2. #2

    Join Date
    Apr 2009
    Location
    doncaster UK
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    Re: More safety warnings needed

    brilliant post and i could not agree more
    over here in the uk we have 240v now that will smart

  3. #3

    Join Date
    Jan 2010
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    USA
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    Re: More safety warnings needed

    I will 2nd that.

    Especially read some things about the GFCI. Its not a complete fail safe.

    Maybe you could weigh in Rygh? I am not an expert.

    I have read somewhere that not all GFCI are created equal.

    And the ones built for commercial purposes would be a much safer solution but should still not be the only fail safe.

    I think the reasoning is that the standards are higher and more defined i.e. you at least get something that doesn't just barely meets code.

    Hope this helps.

    I always thought a separate power strip would be good for heaters. (you could easily switch them off and on with a flick of a switch) Just don't forget.

  4. #4

    Join Date
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    Union City, CA, USA
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    Re: More safety warnings needed

    Yes, different GFCI modules are not all the same.
    There is of course basic quality. Generally relates to longevity and unfortunately, odds of actually working.
    There is the sensitivity. Basically, how much current mismatch before it trips.
    - Tricky. Too much, and it does not protect. Too little, and it false-trips.
    There is the waveform that causes a trip. Sine/pulse/etc. Largely irrelevant.
    There is the time delay before it trips. You want 0.

    Your basic good quality consumer GFCI is what you want. Decently sensitive etc.
    No need to get a fancy high end industrial one. But not a good idea to go super-cheap either.

    Oddly, many industrial ones could be WORSE, since they are often less sensitive on purpose, for less false trips.
    Especially true of computer rooms.
    So don't go out on ebay and buy the first one you see.

    ---
    The power strip switch is a good idea, especially if it controls the pump.
    In theory, you turn the pump off to clean, that turns the lights off as well.

    Maybe obvious to many, but want to mention : A surge protector is not the same thing as a GFCI at all.

  5. #5
    Super Moderator
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    Re: More safety warnings needed

    All good points. Will incorporate it into next faq. Safety was the reason that (1) I added the top shelf on the 100... to keep dripping water off of the lights when pulling out the screen (even though the lighting units are made for aquarium use), and (2) almost completely sealing up the light compartment on the 25... still, however, it will be recommended for the bulb connector to be sealed with silicone (requiring it to be cut out for replacement) if used in a sump area. If set on top of a tank, like most will be, the only air to get to the bulb will be the ambient air of the room, which will not have the salt/humidity.

  6. #6

    Join Date
    Dec 2009
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    Re: More safety warnings needed

    Yes, the SM100 seems very well designed from a safety standpoint.
    Lights are outside the main wet regions, it has a splash guard, and more.
    And in particular, it uses aquarium specific lights, where at least some thought has gone into water-safety issues.

    But since we are on that, two low priority, low risk safety "nitpicks".
    1) The pipe into the system is right next to the ends of the lights, and it is open there.
    Since that is weakly pressurized, you could get a bit of spray on the lights. But closing the end probably messes with your airflow from lights.
    2) You have a slot in the top splash plate for the light cords. Handy, but with the way surface tension works, water pooling on the top could
    easily end up going down that cord, through that slot, and onto probably the most dangerous part of the light.

    And I am obligated to mention that it would be safer with LEDs. :P ... Maybe someday.
    BTW: The highest safe DC voltage is considered around 60V, but telcos and others use 48. LED systems are very unlikely to top that.

  7. #7
    Super Moderator
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    Re: More safety warnings needed

    That's a good point... I'll start sealing up the cords.

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