Announcement

Collapse
No announcement yet.

Florescent light and GFCI likes to randomly trip

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Mr__Bill
    started a topic Florescent light and GFCI likes to randomly trip

    Florescent light and GFCI likes to randomly trip

    I have a number of florescent shop lights that are of the hang and plug in type. The old ones with the T12 tubes still work fine. The newer T12 and the newest T8 fixtures will randomly trip the GFCI breaker. I have swapped out the breaker and it still trips, When I plug them into a GFCI recepticle the same thing happens. It's random, sometimes several times in a day then not for weeks and not always the same light being turned on. I have some CFL that do the same thing.

    I have examined the fixtures for worn wires, and corroded contacts where the lamps plug in finding nothing that looks suspicious. They even pass the sniff test..The problem doesn't seem to follow the weather.

    Is there a fundamental disharmony between florescent and GFCI? Just a sign of old age? The GFCI breakers are about 16 years old.

    Bill
    on the left coast

  • Carlos
    commented on 's reply
    It is weather-rated, but I've also learned there's a "sunlight resistant" cord. And heat may be a factor, since the gazebo is metal and this is Arizona... So when I replace it I'm going to follow a path that is partly sun-shaded and cover the exposed parts with split loom. Also it's been five years so I guess replacing 30' of cord every five years isn't terrible.

  • Slik Geek
    commented on 's reply
    If the cord isn't marked with a "W" suffix, it likely isn't UV-resistant. SJOW, or SJOOW should be UV resistant. (Which means it will deteriorate slower than unprotected cable with UV exposure).

  • Carlos
    replied
    I've been having a problem with my patio and gazebo tripping the GFCI. Only when I'm using it. And only when I start using it. Hmm...what do I do every time? Aside from turning on the fan and lights, I spray the gazebo top, the wall, and the patio pavers with the hose to cool it down (I'm in Phoenix, AZ). But everything is protected from water. I started inspecting the SJ cord that feeds the gazebo fan and lighting...the outer jacket is cracked all over the place. This crap is supposed to be UV-protected. So while the internal insulation was fine, just having water contact against the inner conductors was enough to trip the GFCI.

    Leave a comment:


  • LCHIEN
    replied
    Originally posted by Mr__Bill View Post
    Thanks for all the good advice.
    I did some testing and found that the one fixture tripped the GFCI breaker about 4 out of 10 times I turned the light switch on. One old one new florescent fixtures on that switch. Same fixture plugged into a GFCI receptacle tripped it every time. Other florescent fixtures both old and new and it tripped the GFCI receptacle after about 15 minutes. So I swapped the tripy GFCI with another one and now only the one new florescent trips it. And that dang fixture is now used where a GFCI is not required. I'll be watching for a sale on the LED conversions to go on sale and not buy any more T8 tubes.

    Bill, sometimes in the dark
    on the left coast.
    Good troubleshooting. You had two, and intermittent at that, problems which always complicates TS. One worse than usual GFCI and one worse than usual fixture.
    Last edited by LCHIEN; 06-20-2018, 11:05 AM.

    Leave a comment:


  • woodturner
    replied
    Originally posted by Mr__Bill View Post
    I'll be watching for a sale on the LED conversions to go on sale and not buy any more T8 tubes.
    .
    I started out with the conversion kits, but when the full light kits dropped below the cost of the conversion kits, It was quicker and easier to just replace the fixtures. I have been paying less than $20 for the LED shop lights on Amazon and less than $6 for the single tube fixtures.

    Costco also has good pricing on their LED shop lights from time to time, and people seem to really like those.

    Leave a comment:


  • Mr__Bill
    replied
    Thanks for all the good advice.
    I did some testing and found that the one fixture tripped the GFCI breaker about 4 out of 10 times I turned the light switch on. One old one new florescent fixtures on that switch. Same fixture plugged into a GFCI receptacle tripped it every time. Other florescent fixtures both old and new and it tripped the GFCI receptacle after about 15 minutes. So I swapped the tripy GFCI with another one and now only the one new florescent trips it. And that dang fixture is now used where a GFCI is not required. I'll be watching for a sale on the LED conversions to go on sale and not buy any more T8 tubes.

    Bill, sometimes in the dark
    on the left coast.

    Leave a comment:


  • LCHIEN
    replied
    There are conversion kits to convert fluorescent fixtures into LEDs that will be cheaper than complete units.
    Usually the use the housing and tombstone tube connectors and power cord.
    THe kit will have LED elements that fit the tombstone connctors; you remove all the ballasts and wire the LED driver module between the tombstones and the AC input.
    HArd to screw up but there is a certain amount of cutting and splicing In the end you have the tombstone connecting wires and the AC input and that's all you need to connect to the module they give you.
    Should be a lot cheaper than replacing the entire fixture with LED.. If you must keep on GFCI but want to be rid of those pesky electronic ballasts.

    On the other hand, LEDs will have switch mode power supplies in them as well, maybe just moving the problem. But I don't know, somehow I think the LEDs will be quieter electrically speaking than fluoerecent ballasts, but I can't quite justify it.

    Another solution might be just putting some ferrite beads on the power lines of each lamp unit. It would smooth out the peaky nature of the Y-cap leakage current from RFI and possibly reduce it below the level of the GFCI trip point. If its just a random trip minutes apart then it may just be enough. Your next question would be where to get the ferrites...

    https://www.walmart.com/ip/Ferrite-C...&wl13=&veh=sem

    https://www.amazon.com/dp/B01JMTCC5U...a-502908792392

    I think by 1/2 they mean a 1/2" cord will fit in this clamshell thing. Usually you wrap it a loop.thru the clamshell then close it. Note Amazon costs more but its a two pack making it cheaper.
    Last edited by LCHIEN; 04-21-2018, 04:55 AM.

    Leave a comment:


  • Slik Geek
    replied
    The requirements for GFCI protection seems to get expanded every time the code is revised. I understand why the scope of GFCIs keeps getting expanded because they can be really effective for preventing shock hazards, but It's gotten to the point that on occasion they are required in some applications that you really don't want a GFCI to be required. Here's the relevant code snippet:

    NEC 2008: 210.8 All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specifiedů (see below) ...shall have ground-fault circuit-interrupter protection for personnel.
    (2) Garages
    (5) Unfinished basements (areas of the basement not intended as habitable rooms and limited to storage areas, work areas, and the like)

    If you look carefully at the code, you can see how you can get around the GFCI requirement: it only covers receptacles. If you make the lamp connections to power permanently wired, instead of plugged into an outlet, a GFCI isn't required. Pick up some strain-relief cord connectors (for example, SKU #115383 at the BORG are for 1/2 inch knockouts on outlet boxes and are suitable for 0.260" - 0.375" diameter cords, other diameter sizes are available), and permanently wire the lamps into the electrical boxes.

    Leave a comment:


  • Mr__Bill
    replied
    So much for easy fixes. Local code is 2008 NEC. GFIC's required on all 125V receptacles located in below grade locations, including sump pumps, I'm thinking of buying lots of candles.

    Bill

    Leave a comment:


  • Slik Geek
    replied
    I concur on LCHIEN's "Y" capacitor theory. The electronic ballasts require high-frequency switching power supplies, which generate radio frequency interference (RFI). As LCHIEN described, one of the ways that the ballast manufacturer deals with that electrical noise (and complies with the FCC limits on "unintended emissions"), that the designed includes "Y" capacitors between each side of the AC mains and earth ground. The resulting current to ground is called "leakage current". For safety reasons, this leakage current must be limited below a very low value. Otherwise, if the ground connection is opened, and a grounded person comes in contact with exposed metal that was supposed to be grounded, the person becomes to the conduction path to earth. If that leakage current through the person is high enough, the person receives an electrical shock.

    Note that each device, in this case, each ballast, must comply with the leakage current limit individually. Now imagine some quantity of ballasts connected on the same circuit. Each of them contributes to some value below the allowable leakage current, but the combined value creates enough of an imbalance in the mains supply that the GFCI is near its tripping point. The leakage current varies somewhat, so occasionally the GFCI trips, but not all the time.

    That's my theory, based upon experience designing switching power supplies, complying with EMI limits, and meeting UL safety standards.

    The solution, as others have suggested, is to get at least some quantity of those lamps, or better, all of them, off the GFCI-protected circuit.


    Leave a comment:


  • Mr__Bill
    replied
    Way to go, I thought the ballast might be the problem but never thought of RF much less that the drain to ground would trip the GFCI. It makes perfect sense.

    Way back when we had the place rewired the electrician insisted that because the basement was partially occupied by the garage all 120V receptacles except the garage door opener, washer and sump pump had to be protected with GFCI receptacles or breakers. The house being a duplex with half being rented and the ceiling at 7' may have factored in there too. That's why they are all on GFCIs, I think I'll just swap out the breakers and resist plugging any tools into those ceiling receptacles. Having originally wired with separate circuits for lighting and wall receptacles this will be easy to do. I have already replaced the CFL's on the stairs with LED bulbs.
    In the beginning with tungsten light bulbs and old florescent fixtures there was not a problem. Jump ahead 10 years and we are moving back in after leaving Oregon, and I purchases the cheapest florescent lights from Lowe's to light up the garage and basement to use as a shop, really should have gotten LED shop lights but at the time they were twice the price.

    With the extra GFCI breakers I can add some circuits to the garage so the table saw and shop vac can be used at the same time.

    Thanks

    Bill on the left coast

    Leave a comment:


  • Jim Frye
    replied
    I agree that it is likely the ballasts that are the root of the problem. I have a couple of questions. 1. Why are the lights on a GFI protected circuit? Is this code in your area? In my area, the lights do not need to be GFI protected. Can you put the lights on a non-GFI circuit? My shop circuitry has a separate circuit for lighting (17 LED lamps and 4 75 watt indoor incandescent floods) and a separate GFI circuit for tool power.

    Leave a comment:


  • LCHIEN
    replied
    What you have is a case of electronic ballasts tripping gfci circuits,

    You can google https://www.google.com/search?q=elec...hrome&ie=UTF-8
    and you will see that there's a lot of smoke here... many other people have the probelm.
    THe cause is not so easily pinpointed. I myself (an electrical engineer) presuppose that there is a lot of RFI generated by the electronic ballasts that is not present with magnetic ballasts. Often they decouple this with what are called "Y" caps - capacitors bypassign the RFI to ground. In the case of a GFCI, such current to ground can be considered ground imbalance current and if the GFCI is sensitive (and they are by nature) may be the source of the trip.
    I am not really sure and there seems to be no concensus on all the articles and forum posts you get by googling it. The one that makes sense to me to try would be some ferrite cores applied to the power cords that will potentially dampen the peaks of the RFI currents. But no guarantee,

    One thing to consider is replacing all the newer fixtures with 4 ft. LED ligthing. Probably not what you wanted to hear. It's come way down in price, but yeah you have otherwise perfectly good fluorescent fixtures and bulbs, I hear ya.
    Another possible solution is to add a circuit with no GFCI just for lighting - probably a good idea because if you pop a breaker with a big spinning power tool and the lights go out - that's a real bummer with the tool still spinning down!
    I have my lighting on an original circuit and added four 20A breakers for tools, compressor and DC so they could all run. I put GFCI's on the first outlet of each new circuit, so my 6 fluorescent/LED fixtures are not on a GFCI..

    Good luck to you.
    Last edited by LCHIEN; 04-18-2018, 04:01 AM.

    Leave a comment:


  • Black walnut
    replied
    That does sound strange. Sorry no help.

    Leave a comment:

Working...
X