GFCI adapter and safety ground adapter

Discussion in 'General Electronics Chat' started by paultwang, Apr 24, 2006.

  1. paultwang

    Thread Starter Well-Known Member

    Mar 8, 2006
    80
    0
    I have an electronic device whose chassis is not insulated and does not come with three prongs. I am looking for ways to make it safer by adding a GFCI and/or something that I can plug to mains ground and run a wire to a screw on the chassis. How to go about doing these?
     
  2. alva

    Member

    Dec 14, 2005
    12
    0
    I had the same dilemma, I use an electric lawnmower (120V 9amps) and it
    only had the two wires going into the mains. So after two years of using
    it , without the GFCI or even 3 prong, I got smart and converted it to
    battery power ( the motor is DC and the AC power was bridge rectified).

    I was going to figure out a way to use a GFCI adapter but figured it
    was safer to use batteries and use a fuse on the batteries, the mower runs
    better this way than it does with AC power and is much more mobile.

    I know this doesn't help you any but thought it was an interesting question and
    maybe someone else can respond.
     
  3. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
    24
    If it only has 2 prongs it is more than likely to be double instulated. You are quite safe using these devices because of the way they are designed. So long as you don't mow the lawn in the rain that is.

    I assume a GFCI is the same as an ELCB (Earth Leakage Circuit Breaker)
     
  4. Grant

    Member

    Mar 5, 2006
    17
    0
    Hi,
    You must have alerted yourself to grounding after giving advice in the forum on "what is ground?"!! May I ask what is your "electronic device"? Normally a double insulated piece of equipment with a two prong plug from a reputable manufacturer is designed to be safe if used according to how it was designed to be used. Equipment must pass the country's electrical safety requirements/codes-I know sometimes some articles slip through the net. The metal you refer to- is it actually a "chassis" meaning a frame that the electrical components are directly bolted to, or are you meaning an outer cover that is metal which may be well insulated from any live electrical parts? The reason I ask is because drilling holes in equipment and inserting screws can interfere with other parts and the overall design of the equipment- maybe even causing it to be less safe than it was originally, even though you I'm sure are capable, others may not be. Maybe you do have something that does need to be modified, there is such equipment out there.
    Cheers,
    Grant
     
  5. paultwang

    Thread Starter Well-Known Member

    Mar 8, 2006
    80
    0
    The device is not double insulated. The outer layer is painted metal frame, and I can see the electronics from the vent holes. So should "hot" touches the frame, there is no better ground fault than through the user.

    The device is an adjustable regulated DC power supply. The common port of the DC power supply is shorted to the frame. I don't fully trust the transformer coil to isolate mains AC.

    I have seen and am prepared to buy a commercial GFCI adapter. This should solve the first part of the problem. I am not sure if I want the whole power supply to be a giant EM sink yet.
     
  6. paultwang

    Thread Starter Well-Known Member

    Mar 8, 2006
    80
    0

    GFCI / RCCB works on detecting the current difference between hot and neutral. Ideally there should be no difference in mostly resistive loads.

    ELCB works on detecting presence of current in the earth connections. The problem is, what if there is no earth connection?


    so, no they are not the same.
     
  7. Erin G.

    Senior Member

    Mar 3, 2005
    167
    1
    "Double insulated" does not mean that there is no metal on the outside of the device. It merely means that no electrical / current carrying componants are in any way mounted to, or touch, any exposed metal parts that the user may also touch in the course of operating the appliance.

    You may use a GFCI as a ground. However, do not make the mistake of thinking that it provides you with GFCI protection. 2 prong devices supplied by GFCIs are considered grounded, but NOT GFCI protected.

    Check NEC 406.3(D)(3) for the specifics.
     
  8. jkilla99

    New Member

    Aug 8, 2006
    2
    0
    what are you so worried about; running over the wire with the lawn mower?
     
  9. jkilla99

    New Member

    Aug 8, 2006
    2
    0
    And there is an earth connection through the nuetral
     
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