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Discussion in 'Do It Yourself (DIY)' started by Young Frankenstein, May 12, 2012.

  1. Ebone

    Ebone Well-Known Member

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    question? Do I need a gfci outlet, or can I install a gfci breaker and be covered just as well? Is there a downside?
     

  2. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    You would be just fine with a GFCI breaker. Some people prefer them because they are considered less likely to fail.
     
  3. Ebone

    Ebone Well-Known Member

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    good to know was curious why everyone talks about changing the oulet, when can do the breaker and be done easy everywhere
     
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  4. Ramasule

    Ramasule Well-Known Member

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    Outlet is cheaper.
    Outlet is lower risk of shock. Working off of single de-energized cct vs working in panel.
    Outlet can protect all additional outlets downstream from it, if you need it too.

    There really is no reason to use a breaker.
     
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  5. Joey waid

    Joey waid Well-Known Member

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    If it was me, I would change the breaker.....
     
  6. Ebone

    Ebone Well-Known Member

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    cheaper and aquarium always seems to lead to failure haha
     
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  7. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    One very good reason I have seen is when people cannot access a receptacle behind the tank. It is easier to change the breaker to GFCI than to find an upstream receptacle and change it out.
     
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  8. Ebone

    Ebone Well-Known Member

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    that is my situation, i have an gfci outlet thingy but would rather have the breaker
     
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  9. Ramasule

    Ramasule Well-Known Member

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    To each their own.
     
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  10. LParker480

    LParker480 Well-Known Member

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    Outlet is better for isolating and if tripped, upstream outlets would remain on. Depending on whats connected where, that could be pretty vital.
     
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  11. Floyd R Turbo

    Floyd R Turbo Super Duper Member R2R Supporter Gold Sponsor Toys For Kids 2016 Article Contributor Partner Member 2018

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    Alright here is a good question....

    Some people subscribe to the thought process that their return pump(s) should not be on a GFCI, the logic being that even if there was a ground fault in the system, it's better for the fish to have a circulating water supply. But, we also want to have awareness to the aquarist about this situation occurring.

    So what about this: add a GFCI to the system, somewhere "downstream" of the outlet that feeds the pumps. Perhaps, just for use on a single small device, like another small pump for a reactor or skimmer or something. Plug one device into the GFCI and the ground probe into it as well.

    Now, what happens when there is a ground fault on another device in the system? The way I see it, this would not trip the GFCI because the fault needs to happen on what is connected to the device itself. So in essence, placing a ground probe on a GFCI that is at the tail end of the circuit run can actually act like the scenario where you have a ground probe and no GFCI, which can lead to this:

    or this
    or this
    or this
    So basically, is there any "safe" in-between scenario?
     
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  12. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    I really want to take more time to dig into this and address what you have written, including the older post you have referenced. Unfortunately, I don't have time to get into that right now. The one thing I do want to quickly say is that where the ground probe plugs into the system has no impact on any fault conditions. All of the house grounds, including properly designed power strips that are plugged in, should always be connected and are not disconnected by a GFCI opening. A GFCI also does not care where the ground current flows since it doesn't measure ground current. If the faulted device is inside the zone covered by the GFCI it will trip even if the ground probe is plugged into a separate circuit on the house. If the faulted device is on an outlet before the GFCI, no GFCI trip will occur even if the ground probe is plugged into a GFCI protected outlet.
     
  13. Floyd R Turbo

    Floyd R Turbo Super Duper Member R2R Supporter Gold Sponsor Toys For Kids 2016 Article Contributor Partner Member 2018

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    Right...that was my point, I guess.

    Obviously, if the faulty device trips the GFCI, it will no longer have power, thus no current (from that device's fault) would go through the ground probe.

    This basically raises the issue of GFCI & ground probe when all devices are not on the GFCI. This is a situation where one could think they are protected, when in fact they are not, and in a way that specifically could start a fire under certain circumstances.

    Kinda leads you to the "all or nothing" type of philosophy. Either you have everything on GFCI and then have a ground probe, or you only have certain devices on GFCI and no ground probe. But you can't have it both ways.

    Seems like the missing element here is a current sensor on the ground...something that wouldn't shut everything off, but would sound an alarm to let the aquarist know that something is not right = don't reach into the tank!
     
  14. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    Personally, I feel that the fear of high current from using a ground probe without a GFCI is overblown. If you have a heater or motor casing crack, the water will short between the the hot to the neutral. In this case, the neutral is the exact same thing as a ground probe.
    It's issues like this that make me want to really dig into this.
     
  15. Ramasule

    Ramasule Well-Known Member

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    Safe go between:
    Use an external return pump not on a GFCI.
    If you are so concerned about a faulty pump on a gfci tripping then get an external pump.

    Windings in a motor block are still going to be laminated. So you have to have, failure of motor block, failure of windings (Although easily corroded by salt water).

    If I absolutely could not put in a GFCI but decided to add a ground probe I would not connect it (ground it), instead I would use it as a fault indicator and connect one end of the ground to a light bulb or led and the other to ground. My selected voltage would probably be 48v to signal fault situation.

    The reason we see power bar and outlets destroyed (Fire) is because the fault is not staying on the typical conductive parts of the power system. The fault is establishing across plastics which in turn heat up, break down, oxidize?(Turn to carbon) and further conduct.


    Scenario 1: Probably going to be very low current. Would not use this scenario, would use ground as indicator.
    Scenario 2: I'm going to assume H-N short in same device. Current should be high enough to trip breaker unless you are talking about a turn-turn fault in a motorblock, or something like that.
    Scenario 3: Against code to have a non grounded metal body, non scenario.
    Scenario 5: Should not do anything unless house is wired incorrectly (Switched neutrals on lights) and another cct raises neutral potential.
     
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  16. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    These are both fantastic suggestions!
     
  17. Floyd R Turbo

    Floyd R Turbo Super Duper Member R2R Supporter Gold Sponsor Toys For Kids 2016 Article Contributor Partner Member 2018

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    Curious: why does this make a difference? Can't an external pump have a situation that would trip a GFCI?
     
  18. Brew12

    Brew12 Electrical Gru R2R Supporter R2R Excellence Award Reef Squad Build Thread Contributor Article Contributor Partner Member 2018

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    It can, but since the pump isn't in the tank it will not leak voltage/current into the tank.

    This is the same basis as for why I use MP40's in my DT. The motors aren't in the tank and I consider them more important to my tanks short term health than my return pump. So my return pump is GFCI protected but my MP40's are not.
     
  19. JBradford

    JBradford Well-Known Member

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    Electrical question and it has nothing to do with a tank. I have a 220v line (3 pin) running to my kitchen for an electric range, however, I have a gas range that does not use the 220v plug. I also don't foresee me going to an all electric range.....ever.

    I want a 220v outlet in my garage for a compressor (4 pin).

    I have everything to run this 4 pin outlet. I do not have an extra spot in my panel for a breaker to run a dedicated line to my compressor.

    Can I safely 'tap' into the 220v line in the attic and run it over to my garage? If so, do I need to change my compressor over to a 3 pin plug to make this an easier/safer installation?
     
  20. Ramasule

    Ramasule Well-Known Member

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    An external pump will not be subjected to constant contact with salt water and will more than likely never fail. (The motor windings that is, not the bearings, pump seal, etc.)
    Furthermore if it does fail (windings) it will be a winding/winding short and will cause an increase in motor temperature which (Should) trip the internal motor overloads, or further cause an upstream breaker to trip.
    If you wanted to GFCI your external motor you would be looking for a condition where there is a winding to case fault. This would have to be in the near the bottom of the winding to not cause the overloads to trip and would probably place your motor case at such a low voltage you would not notice if you touched it anyways.


    I for one would follow somthing close to @Brew12 design if you are concerned about loosing water circulation on a gfci trip, where in your return pump and wave makers are on separate gfci ccts or separated somehow. It will not be the return pump stopping that kills the inhabitants, it will be the lack of surface exchange.
    Furthermore for the ultra paranoid you could hook a 120VAC relay up to the same power as your return pump. Then take the NC connection of said relay to power up a 12/24 pump or fan connected to a battery bank. Should the power shut off to said relay the contacts will close powering up your fan or pump that will agitate the surface of the water.
    Or buy 2 pumps.
    Or train a fish to swing valves in case of a pump failure.
     
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