Ground Fault (GFCI) plugs

richyoungrichyoung Danville, CA
edited July 2003 in Hardware
Has anyone found a GFCI plug that will work with a PC? I have my pump and fans under the house so I wanted them on a ground fault circuit. This works fine. Only problem is when I add the PC to the circuit the GFCI trips on occasion. If I leave the PC off the GFCI circuit I run the risk of the pump shutting down with PC still running. Thanks, ...Rich

Comments

  • edited July 2003
    Ok, that can happen if the ground is not perfect or if a surge is passed back from a surge protector back into a GFCI protected circuit that is not bonded to an earthing rod. Ideally, you surge supporess beofre power gets to the GFCI outlet, which is not cheap (not hyper expensive, a spark gap surge protector will fix your GHFCI choputs if that is the only cause as big surges will neve get to your computer's surge protector this way).

    So, you have a cooling system that is GFCI'd, but the GFCI should not be your safety-- a temperature triggered shutdown device is what you need, with software that will shut down the O\S also.

    John Danielson.
  • OldDogOldDog Whittier,Ca.
    edited July 2003
    You could try using an inexpensive flow switch on your incoming water line to shutdown your computer. Then you can take your computer off the GFCI with the same result if the pump fails.
  • richyoungrichyoung Danville, CA
    edited July 2003
    Originally posted by Ageek
    Ok, that can happen if the ground is not perfect or if a surge is passed back from a surge protector back into a GFCI protected circuit that is not bonded to an earthing rod. Ideally, you surge supporess beofre power gets to the GFCI outlet, which is not cheap (not hyper expensive, a spark gap surge protector will fix your GHFCI choputs if that is the only cause as big surges will neve get to your computer's surge protector this way).

    So, you have a cooling system that is GFCI'd, but the GFCI should not be your safety-- a temperature triggered shutdown device is what you need, with software that will shut down the O\S also.

    John Danielson.
    The ground test out. Not sure I fully understand the surge comments

    Do you know where you can buy a temp trigger? Thanks, ...Rich
  • richyoungrichyoung Danville, CA
    edited July 2003
    Originally posted by OldDog
    You could try using an inexpensive flow switch on your incoming water line to shutdown your computer. Then you can take your computer off the GFCI with the same result if the pump fails.
    Do you know where "an inexpensive flow switch " can be purchased? I didn't see any online except for high pressure devices. Thanks, ...Rich
  • edited July 2003
    Um, hmmm....

    Basicly, if you have all the computer gear using one cord into GFCI and the pump using another cord into GFCI, you can get a grounding potential problem if the grounds are not perfect and beyond capacity needed. Plugging a device that is grounded itself and grounded with GFCI can cause an earthing or grounding potential problem.

    I will give you an illustration:

    We had a GFCI circuit in the house,and someone stuck an outdoor light on that circuit-- but two bathroom circuits and a computer\fax\answering machine in a microoffice were on the circuit.

    When a fax came in while dad was shaving, the GFCI outlets all blew. When the outside light was on and I used a hair dryer, the GFCI outlet in my bathroom AND the GFCI breaker blew. We now have 4 GFCI circuits. Now the one for the dock light outside only blows when someone leaves the flap on the outside outlet on the light post open and it rains.

    If you said the pump is on or underground, you could try what me electrical contractor grandfather did with the emergency sump pump that kept not pumping under the crawlspace. He put it on a rubber sheet and stuck that on a piece of big plywood and made sure nothing metal connected to it went to anything except the grounded outlet. And stuck it on its own circuit. I would make sure that the two things were ground isolated from each other.

    Different potentials can cause GFCIs to blow at apparently random times, whenever the differences in ground potential vary-- even from outlet to outlet in a circuit.

    If your pump is chassis grounded you have the potential for two ground routes whenever the ground is damp if it is on the ground-- wet pump, mateal pump touching earth itself, both will do this.
    And a GFCI outlet will protest that possibly also. If you want a safety chassis ground, make sure only the pump is on the GFCI. In your case, you have not said this happens with only pump on, so I think you are getting a potential-difference-induced flow across outlets(two in a duplex) that is triggering it at least in large part.

    Computer can be off the GFCI or on a separate one, or a breaker might be used instead of a duplex outlet-- unless you are using metal-fiber-reinforced hosing. The story behind that fact is not repeatable in detail, and involved someone powerwashing a house barefoot with an old rented electric power washer. Suffice to say the ending was a ground flow that was not supposed to happen and the GFCI never chopped. The power washer was grounded-- AND shorted, via the metal reinforcing in and fittings fastened onto both ends of the hose. Wrong hose-- air compressor line.

    Unless GFCIs are old and corroded, it has to be a grounding potential problem or a wiring problem with neutral and ground crossed somewhere in the circuit or the things hooked to it.

    John Danielson.
  • OldDogOldDog Whittier,Ca.
    edited July 2003
    There's no practical reason for your computer to be GFCI protected anyway. You might try industrial supply houses for a flow switch. Remember though that you want flow, not pressure. Most flow switches require very little pressure at all, just movement of liquid in the pipe or hose. There are a lot of variations on the theme, and many are made to run a pump when someone opens a valve. You might try someone who sells small pumps.
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