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MES tripping GFCI

Discussion in 'Electric Smokers' started by buckman52, Sep 22, 2010.

  1. buckman52

    buckman52 Newbie

    I am taking the advice of Bearcarver and starting a new thread with my problem.  I am reposting my 2 postings here so hopefully someone out there can help me out.

    POST #1
    This is my first effort at amy posting anywgere so please bear with me.   I have a MES 40" that I have had for about 18 months that has stopped working.  However I do not seem to be having the same wiring problem that has been described and resolved so wonderfully here.   My MES powers up fine and the electronic control works.  I can program in the target temp and the time just fine but as soon as it tries to turn on the heating element it trips the GFCI.  I have tried a different outlet and that one triped also.   I have removed the back and I cannot see any problems with any of the wiring,   Any suggestions????

    POST #2
    Unfortunately there is no access panel so I drilled out the umpteen hundred rivits.  There is no visible evidence of any wiring problem.  None of the wires are scorched or turning brown.  All the connections are tight and clean.  Wiring does not seem to be the problem which leads me to think that it is an electronic problem.  I am fairly good at fixing electrical wiring problems but I am at a complete loss when it comes to "electronics".  There is a "box" mounted in the bottom panel that I looked in and there is no indication of a problem there.  I contacted MES and since it is a discontinumed model all they could do is offer me a discount on their new model.  I'ld love the new one but there is still too much life in this one if I can bring it back from the dead to be shelling out that kind of money yet.  Anybody know anything about the controler box in the bottom?

    Thanks for any ideas.
  2. mossymo

    mossymo Master of the Pit OTBS Member SMF Premier Member


    Try plugging it in and using it on a normal (non-GFCI) outlet. The sump pump in our basement will not operate on a GFCI outlet, it trips it every time; so we keep the sump pump plugged in to a normal outlet.


    After 5 years my 30" MES all of sudden started powering itself down within seconds of it trying to power up the burner. I removed the back panel and all the wiring appeared fine, Then I opened up the box that house the 2 polarity connections and the ground connection, these appeared relatively clean but I disconnected each of them anyways and the ground connection had quite a bit of creosote build up which I cleaned up. Reconnected everything and powered it up and it was working normal again. After that I put the back panel back on and so far it has been working fine.

    If you have the same issue as I had with problem #2, it may explain problem #1 with your GFCI..... to test plug your MES into a normal outlet too see if the burner powers the MES down.
  3. dale5351

    dale5351 Smoking Fanatic

    It may not be possible for him to reach a non GFI circuit without a long extension cord -- which is not recommended.  My MES is on my deck and the plugs out there are GFI.   Next is my kitchen and all of the circuits there are GFI (which is appartently now code -- although it did not used to be).   I'd need a 50 foot cord to reach a circuit that is not GFI.

    Your suggestion about cleaning the contacts sounds worth a try.
  4. mossymo

    mossymo Master of the Pit OTBS Member SMF Premier Member


    Even if it were to be plugged in to a normal outlet in a dining room, living room, ect. without an extension cord too test the MES to see if the the burner turning on, powers the unit off. This is just to test, I was not suggesting buckman52 smoke two 6 pound butts in his living room. [​IMG]
  5. what else do you have plugged into the circuit that it is on?  circuit could be overloaded....try powering it up on a completely different circuit, i.e. one that works when the breaker for the gfi in in off position, and see what happens.
  6. dale5351

    dale5351 Smoking Fanatic


    Perhaps he has a non-GFI circuit in his garage?

    The visualization of smoking in the living room appeared to me after I wrote that -- but I didn't get back to edit before you posted it.

    I've been through a house fire (30 years ago) and can remember the difficulty of getting that smoke smell out of the house. 
  7. dick foster

    dick foster Smoking Fanatic

    If you are absolutly certian that the GFCI outlet is OK, the outlets do go bad, I would probably start with a good ohm meter to find what part of the circuit is leaking current to ground. Or try isolating parts of the circuit starting with the heaters until you find the part of the circut that is tripping the GFCI. Basicly GFCI circuits do two things they look for as much current coming back to the return or white wire as left the hot or black wire and they look for current on the saftey ground or geen wire. If they don't see as much current on the white wire or return of if they seen any on the saftey ground or the green wire they will trip. Like someone else mentioned if you have cresosote build up or moisture or something shorting current to the chassis, then that could be your problem. Then too it could be a component that went bad. First of all, find the part of the circuit that contains the problem by isolation then fix or replace what's wrong.   
    Last edited: Sep 22, 2010
  8. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    OMG the things my wife would say when she saw the smoker in the living room. LOL

    I am no electrician so take this for what its worth.

    The last several work trucks I have been given to drive at work have had block heaters. All of these trucks have had block heaters and all would trip a GFI. Dont know why but they do. The truck I drive now must have an actual problem since if my feet are wet and I touch the metal while its plugged in, it will knock ya for a loop.

    I have heard tho, that there is alot of GFI troubles with heating elements. I wish I had a solid answer for ya.
  9. buckman52

    buckman52 Newbie

    Thanks for all the help.  I did (as suggested) plug it into another non gfci protected outlet and it did not trip the circuit.  However after 20 minutes it had not generated any heat either.  I'll try to play with it later and see if I can find a bad connection.  I wouldn't have any idea how to use an ohm meter.
  10. sounds like you have a short in your smoker somewhere....if it works on a normal outlet but doesnt heat up and throws the gfi outlet, you problem is at the smoker.
  11. dick foster

    dick foster Smoking Fanatic

    Then find someone who does and let them mess with it. If you're not comfortalbe with mechanics you should not take your car engine apart either. The same thing applies here. However the little bit of electrical here is a lot less complex than taking a car engine apart and putting it back together.  
  12. deltadude

    deltadude Master of the Pit OTBS Member

    It sounds like the relay is bad.  You said the controller looked like it was working, except when it tried to switch on the element.  The controller is on the low voltage side of a relay, and the relay has a coil in it that when the controller triggers for heat current is sent to the relay and the coil engages the high voltage side and allows 120v to flow through to the heat elements.

    Below is a rough schematic provided by   sparksnsaaben in this thread

    As you can see there are only 4 items on the high voltage side of the circuit,  transformer which provides low voltage, the element, thermal cut off which is just a switch, and the relay.  Again since the low voltage controller appears to work, thus the transformer appears good, that leaves the element which might have a piece of the connector touching the metal case and thus a short when controller triggers the element.  Next the thermal cut off, really not likely, you can pull off the leads and connect them directly to see if this is the problem.  Last is the relay.

    Check that element closely where it goes through the case.


    Hope this helps,,   good luck...
  13. buckman52

    buckman52 Newbie

    Thanks for the schematic.  At least now I have some idea of what is going on.
  14. thundernoggin

    thundernoggin Newbie

    Could be a bad element.  We see this exact problem in spa heater elements all the time.
  15. dick foster

    dick foster Smoking Fanatic

    It shouldn't be causing the GFCI problem but for the no heat problem those thermal cutout switches are well known hi failure items.

    The ohm meter should indicate a short circuti across it if it's good. If it reads open, or high resistance, it's bad.

    The GFCI problem is probably going to be some sort of contamination leaking current to ground or a bad heating element that has perhaps burned open then the heating wire shorted to chassis ground.
  16. dorel

    dorel Newbie

    I have a similar situation, my electrical heating element works if its disconnected from its place inside the smoker, but when its inside installed normal trips the GFI.

  17. old sarge

    old sarge Master of the Pit OTBS Member ★ Lifetime Premier ★

    Plug an plain old iron or electric skillet into the outlet you use and crank up the heat.  If the GFCI trips, check its wiring and replace the outlet. If not, then your smoker is the problem.  From a pure safety aspect, I would spend the money and get a new smoker. Money can be replaced with another week of work. Electrocution is sort of permanent. 
  18. daveomak

    daveomak Epic Pitmaster OTBS Member SMF Premier Member

    Bypass the electrical circuitry in the smoker and wire in a dimmer switch.... You will have to use an external therm to monitor the temps... I have a dimmer on mine and the temp control is far superior.... I can regulate the heat output.... like a gas burner regulation... OR, wire in a PID ..... OR wire in a temp controller to the element....

    Find one that fits your needs and budget....

  19. leefra

    leefra Newbie

    I agree with thunder. It sounds to me you have a bad heating element. It is either shorted internally or leaking internally to the outside casing wich is grounded. GFI are not made to trip on overload, only on leakage to ground.
    Try this.
    Disconnect the one wire feeding the element (should be black or colored, as opposed to white) and see what happens. It it functions normally ( with no heat of course), it's likely to be the element is shorted and should be replaced...
    This is from a retired electrical contractor.
    ABC....always be careful😉
    Last edited: Dec 1, 2014
  20. The reason is, the ceramic potting inside the heating element is porous and moisture gets in and causes a small amount of current to leak to ground through its high resistance and trips the GFI.  Try this, with the power removed, BE SURE all electric power has been removed, remove the back panel for access to the back of the heating element.  When you can see the heating element, be sure the outside of it is not touching any of the metal on the smoker, if it is you may need to remove the heating element and with a drill make the hole larger so the heating element can not touch the metal of the smoker, just a thought, something to try

    The GFI measures the difference in the current on the black ( hot ) going to the heating element and the white wire ( return )  back from the heating element.  If the difference is 180 MA ( I think) or more it trips the GFI.  The GFI is not made to trip from load, only from leaking current.  have the same problem in my sisters new kitchen, every outlet is GFI, nothing works, the toaster trips it, the coffee pot trips it, the refrigerator trips it, the crock pot trips it, the electric pressure cooker trips it, the electric roaster trips it/  The only things that work are the mixer and the microwave oven because they do not have heating elements in them. 

    Ohms law says resistance is E (volts ) over I  ( amps)  we know the  smoker is 120 volts and the label says it is rated at 15 amps so 120 over 15 is 8 ohms.  Ohms law also says that watts is E (volts) times I (amps) so 120 times 15 is 1,800 watts, the smoker is 1,800 watts of heat at 8 ohms, if the resistance has gone up to 10 ohms, the current is now  120 over 10 = 12 you are down 3 amps and the heat is now 120 times 12 = 1,440 watts you have lost 360 watts of heat...in just 2 ohms !

    best 73's  DE  WAØAUU for 60 years !