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OT: Gas dryer tripping GFCI

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  • OT: Gas dryer tripping GFCI

    I have a GE propane gas dryer DSJR473GT3WW that I bought for less than $50 maybe 20 years ago, and it has been working well for all that time, on a "temporary" 20 pound gas bottle connection. I have the washer and the dryer plugged into a GFCI outlet. Last night, after washing some clothes, I put them in the dryer and turned the timer control to an appropriate setting. The GFCI immediately tripped. I tried several times, and then pulled the control panel to see what was wrong.

    This is the timer switch with two wires removed that kept the GFCI from tripping:



    Here is another view of the components and wiring:



    My multimeter showed intermittent high resistance (>100k) on some of the connections to ground. It seemed like there was a problem with the neutral where the power cord came in at the bottom back corner. There is a single wiring harness with maybe 10 wires but it seemed to require major disassembly of the machine for access.

    I decided to use my HiPot to check the insulation of the power wiring, but it was stored in a damp place and needed some cleaning.



    When I plugged it into the GFCI, it also tripped, so I figured there might be problems inside:



    It looked OK, although there was a lot of white powdery corrosion on the metal parts of a couple potentiometers. Then I tried plugging it into another GFCI and I was able to turn the test instrument on without tripping.

    So, it seems I have a too-sensitive GFCI. Perhaps I can test it to see what current level trips it.

    I wasn't able to find an exact schematic for the dryer, but here is the user manual:
    http://enginuitysystems.com/pix/hous...SR473GT3WW.pdf
    http://pauleschoen.com/pix/PM08_P76_P54.png

    Paul: www.peschoen.com
    P S Technology, Inc. www.pstech-inc.com
    and Muttley www.muttleydog.com

  • #2
    GFCIs do go bad. You seem to have one such. Replace it and move on, as long as the test button on the new one trips it.
    1601

    Keep eye on ball.
    Hashim Khan

    Comment


    • #3
      I've had several GFCIs go bad. One was outside and was not adequately sealed, so water got in. Another was inside, but in a damp area. This one is mounted on a rear wall below grade and also a damp location. I did buy one or two that are rated for damp locations. I think that's what I need to use.

      Now I have the dryer running on the GFCI for the stove. I'll deal with replacing the touchy GFCI later.

      Thanks.
      http://pauleschoen.com/pix/PM08_P76_P54.png

      Paul: www.peschoen.com
      P S Technology, Inc. www.pstech-inc.com
      and Muttley www.muttleydog.com

      Comment


      • #4
        you need a new GFCI and while your out, pick up some new test equipment. Is your VOM also analog (no pun intended)

        Comment


        • #5
          An older dryer is a perfect component to trip a GFI, does it run for a bit at first then trip?

          the combination of lint build up and high humidity can be enough of a connection to ground to trip one off,

          if it works at first and then trips or if your new one trips also then this is where you probably should focus your efforts next.

          Comment


          • #6
            Originally posted by 3 Phase Lightbulb View Post
            you need a new GFCI and while your out, pick up some new test equipment. Is your VOM also analog (no pun intended)
            That is probably a perfectly fine leakage tester. What do you think is wrong with it?
            1601

            Keep eye on ball.
            Hashim Khan

            Comment


            • #7
              yes, and don't trash analog VOM... Sometimes they are perfect for certain applications. I still have a couple among my array of digital gear.

              Comment


              • #8
                Originally posted by J Tiers View Post
                That is probably a perfectly fine leakage tester. What do you think is wrong with it?
                To name a small amount of issues... No vertical ranges, no min/max samples, no back-lit LCD/TFT digital display, no firmware upgrades available, no Network/USB/GPIB interfaces to automate control/measurements, no traceable NIST cal data.

                Comment


                • #9
                  Originally posted by 3 Phase Lightbulb View Post
                  To name a small amount of issues... No vertical ranges, no min/max samples, no back-lit LCD/TFT digital display, no firmware upgrades available, no Network/USB/GPIB interfaces to automate control/measurements, no traceable NIST cal data.
                  And you need all that to find out why one of your household appliances isn't working?

                  Comment


                  • #10
                    Originally posted by 3 Phase Lightbulb View Post
                    To name a small amount of issues... No vertical ranges, no min/max samples, no back-lit LCD/TFT digital display, no firmware upgrades available, no Network/USB/GPIB interfaces to automate control/measurements, no traceable NIST cal data.
                    I gotta agree with cameron unless you actually intended your post to be some amusing sarcasm. How did we ever get to where we have all these things without those things? Yep, we used regular analog tools to build the first digital tools.

                    Now I'm all in favor of the new world. I would never have paid the cost of a nice old CRT scope back in the day. And now I can buy a digital scope or a scope module that attaches to a PC or tablet for less than I pay for the wood to build a nice bench to put it onto. It's a wild and whacky world out there......

                    Comment


                    • #11
                      Originally posted by 3 Phase Lightbulb View Post
                      To name a small amount of issues... No vertical ranges, no min/max samples, no back-lit LCD/TFT digital display, no firmware upgrades available, no Network/USB/GPIB interfaces to automate control/measurements, no traceable NIST cal data.
                      So what?

                      NIST is relatively easy, if you have a recently calibrated meter and probe. I usually keep at least one in-date calibrated meter around. The rest of it is pretty much "fluff" as far as actual standards are concerned. Similar, but a bit newer, testers from Rod-L and others, are used in production testing in factories, and are deemed suitable.

                      Of course they produce current testers that provide some of the things you asked for. But the device Paul shows, if working, is entirely sufficient to check for faults.
                      1601

                      Keep eye on ball.
                      Hashim Khan

                      Comment


                      • #12
                        As I said, there is nothing wrong with the dryer, OR my leakage tester. It is definitely the GFCI, and at least it failed "safe", rather than being insensitive and allowing too much leakage current to flow. I am just curious about the calibration of the GFCI, which can be easily determined by putting a suitable decade box or rheostat from line to GND. I think the usual trip point is about 5-10 mA, which would be about 25k to 10k.

                        A hipot tester like mine goes for about $60 used:
                        http://www.ebay.com/itm/SLAUGHTER-Se...-/332390241354



                        But that one is AC and mine is DC. There are pros and cons for each.

                        Maybe I should get one like this for $3800? Yeah, right. If mine goes bad I know I'll be able to fix it. If this one goes bad, I'd probably have to send it to the manufacturer or an authorized repair center for a couple hundred bucks, and if it's too old, I'd be SOL:
                        http://www.ebay.com/itm/Quadtech-Gua...-/172903893279



                        Actually, among my design projects are a high voltage insulation tester, a DLRO (Digital Low Resistance Ohmmeter), and a TTR (Transformer Turns Ratio) tester.
                        http://pauleschoen.com/pix/PM08_P76_P54.png

                        Paul: www.peschoen.com
                        P S Technology, Inc. www.pstech-inc.com
                        and Muttley www.muttleydog.com

                        Comment


                        • #13
                          Most dielectric testers will not work on a GFCI because of how they operate, most will not work without a working bond either.
                          A GFCI is not required for a washer or dryer though so why not just toss it and install a standard receptacle?
                          If your interested to check for leakage I would recommend a megger rather then the dielectric tester as it is less likely to let out the magic smoke in older appliances and equipment that has been around awhile, a highpot is a destructive test after all.
                          Good luck!
                          Jon

                          Comment


                          • #14
                            Hipot is NOT a destructive test at all.

                            That presumes you are testing to a standard, which means you turn up to the voltage, leave for the dwell time, and turn down. The unit passes, or it does not pass. If it passes, there is no problem. If it does NOT pass, then you have lost nothing, since it was defective to begin with.

                            If you simply turn up until it fails, well, that is a different issue, and that could presumably be destructive. As can many other tests, if you have no clue what you are doing.

                            Both line and neutral, or all lines for US 240V, or any 3 phase, should have full insulation from earthed parts, suitable for the standard established "Hipot" tests. There should be no parts between those two which the standard tests can damage, since there should be no break down.

                            The one "kicker" in the deal is MOVs or other similar protectors. Those will generally break down before the specified limits (well over mains voltage), and some tests should be made only with such parts disconnected.

                            The difference between AC and DC testers is that in case of EMI filters in the unit, the high voltages would pass unusual currents if tested with AC. That can easily show a "fail" which does not actually exist. Testing such units with DC is done to avoid those issues.

                            If you look at the standards, the test duration and voltage is often different if testing with DC instead of AC. But either is usually acceptable.

                            For testing GFCI units, the 115V units are provided with a "test" button, which does use a resistor to ground. If the test button trips the GFCI, you are entitled to consider it is working. That does NOT guarantee that it is not OVER-sensitive, but it assures that the unit will function, and that it is at least up TO the required sensitivity (it could be MORE, but not LESS sensitive).

                            With a 240V unit for dryers, etc, there may still be a "test" button, in which case nothing further should be needed. If not, assume a 5 mA limit and use that. Class-A GFCIs are 5 mA, suitable for protection of people. There are ones for equipment protection with higher limits of 10, 30, 100 or 300 mA, IIRC. Those are totally unsuitable for protection of people (even the 5 mA is by no means "safe" for everyone in every situation, but it is a good average).
                            1601

                            Keep eye on ball.
                            Hashim Khan

                            Comment


                            • #15
                              For hipot testing of transformers, motors, and other inductive loads, it is usually recommended to connect a shorting jumper across the power terminals. Then you can safely test from each coil to ground, and from coil to coil. A fault will often prove to be something like a strand of wire, swarf, carbon powder, or damp ionic contaminants such as salt. Such breakdowns sometimes clear the fault, or locate it by visible arcing, and is usually non-destructive. Hipots are generally current limited to a couple hundred mA or less, and will trip an overcurrent device and sound a buzzer when breakdown occurs.

                              Without shorting the inductive components, the application and removal of voltage can cause inductive transients much higher than the hipot voltage, and can cause damage.

                              I am pretty sure I need a GFCI for this application. The washing machine is next to a utility sink, and the dryer is next to the washer. Then there is the refrigerator and the electric hot water heater in the corner. The GFCI feeds both the washer and dryer, but has never before been a problem. It is an older GFCI without an indicator lamp. The dryer works perfectly well on the newer GFCI that supplies the propane gas stove. It is adjacent to the cabinet with the kitchen sink.

                              https://diy.stackexchange.com/questi...-a-new-circuit

                              http://advanceelectricaltraining.com...ci-protection/

                              http://homeguides.sfgate.com/type-ci...yer-91181.html

                              http://www.ecmweb.com/code-basics/ne...errupters-gfci

                              https://www.thespruce.com/nec-regula...-gfcis-1152273
                              http://pauleschoen.com/pix/PM08_P76_P54.png

                              Paul: www.peschoen.com
                              P S Technology, Inc. www.pstech-inc.com
                              and Muttley www.muttleydog.com

                              Comment

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