Well, if the circuit that maloff28 ran the smoker from is NOT on a GFCI, then we still have not determined whether or not the smoker has a fault.
It is possible (likely?) that the smoker is showing some leakage current from hot to ground, and that trips a GFCI. But he can bypass the GFCI receptacle by running a long cord to
an outlet that is not protected by a GFCI, and everything runs fine. The problem would then be that there's still a fault which the GFCI was protecting him against, but which the non-GFCI outlets are not protecting him from.
I'd still make the ohm-meter tests described by KeithD above. But you can have a leakage path that requires higher voltage to break it down, too, and that wouldn't show up with an ohm-meter's low testing voltage. You'd need a "megger" to ring that out.
So I'd do the test of the GFCI with a hair dryer and if it works fine with other things plugged in, (and we know it tests as being wired correctly with the test plug thing), then I'd be suspicious that there is a fault in the smoker.
It would be so easy for some moisture to get where it shouldn't be, and maybe some smoke residue, and create a relatively high-resistance leakage path inside one of these smokers that it would surprise me if quite a few of them didn't/haven't ended up with leakage faults. As was pointed out, GFCIs can be very sensitive. That's a good thing in many ways. But the amount of leakage required to trip the GFCI can easily be so low that it won't keep the appliance from appearing to operate perfectly. If the leakage path "burns" over time, it could get worse and worse and eventually cause a fire in the smoker or create a hazard. The frames/cases of the smokers are grounded. So ideally, there would still be no shock hazard because the leakage is going to ground via the grounding conductor. But you really don't want to allow that kind of thing to just go on and on.
You could get a new GFCI protected outlet strip or power cord and plug that into the same outlet (requiring the extension cord(s) you've been using "successfully") with the smoker and see if THAT GFCI trips. If it doesn't, then you may have a "too sensitive" GFCI and just need to replace it. But if that new GFCI cord trips, then it seems pretty likely that the smoker does have a leakage fault. At that point, you'd want to have it serviced by a competent repair person to have the leakage path found and corrected IMO.
The GFCI is on the outlet not the breaker. I will have to pick up one or both of those gadgets to check things out further. I was able to run the smoker all day on an outlet on another circuit, but, I had to string two extension cords together to get to that other outlet and I know that is a no-no.
All the points above are well taken. I Need more information on where the problem is.
The main no-no here is not that you've used the extra extension cords (although that's not good), but more that you've bypassed the GFCI, which is (presumably) there to protect outdoor outlets where shocks are more likely to be an issue due to people standing in water, on bare ground, etc. I'm assuming that the outlet you plugged the extension cords into is NOT protected by a GFCI. If it is, forget everything I've been saying!
I bought the circuit checker and believe it or not the outlet tested fine. I did not buy the volt meter as I was not sure what kind to buy, plus I was not sure I wanted to make that investment, not knowing how expensive it would be.
I also bought a 12 gauge extension cord. I have not tried to heat the unit with the new extension cord yet.
If anyone has a recommendation for a volt meter that won't break the bank, I am open to that too. I will try this week heat the unit with the new cord and see what happens.
Even if the GFCI was bad, the circuit wiring may well pass the tests that the test plug provides.
I really like the Fluke digital volt meters. They're a bit more than many of the inexpensive ones, but you will probably never need to buy another one in your life. I've got one I purchased in about 1978. It's still vastly superior to just about any other meter I happen to pick up to use. I often end up setting the cheapie meter down and trekking back to my office or wherever I left my tools so that I can use "my" meter because I trust it and am more comfortable with it and confident of the readings I get.
And on that subject: I've forgotten, and had it set to ohms many many times and stuck the prongs into an outlet or connected it inside something to test for 120VAC, and it's never protested in the slightest. That's one difference between a higher quality meter and a cheapie. With some meters, that would have been the end of the meter and potentially dangerous, to boot. But with the old Fluke, it just gives me a strange reading on the meter and then I smack my forehead and am once again grateful that it can stand up to my stupidity. I've even seen them plugged into 120 when set up for reading current. That just blows an internal fuse.
With a cheaper meter, that often results in a pretty spectacular display of pyrotechnics.
The other thing that annoys me pretty much every time I try a different meter is the speed of getting a reading. That seems like a trivial thing, but when you do a lot of this work, it's really aggravating how slow some of the meters out there are. It's just a lot of little ergonomic things that add up. I'm sure people are passionate about other tools we use, and have favorites and subtle reasons why others just don't feel right to us. That's the way it is with these meters. The Flukes, even my old 1978 model, just work better, faster, safer, and just "handle" better.
Looking on
Amazon, for prime-eligible Fluke meters, they've got this one:
There's also this one with a temperature function:
Not cheap, but if you're in the mood for a tool that will probably last a lifetime...