grumpykidstudio Posted December 21, 2020 Report Share Posted December 21, 2020 Hey guys! I have been using my 28 amp kiln on a 30 amp breaker, but i had to replace control board recently, and the technician said I will trip my breaker if I keep running on a 30 amp breaker.... I have no option but to keep using this breaker, do you think it's safe? If no, do you have any reccomendation for small volt kiln that can run on a 30 amp breaker? Link to comment Share on other sites More sharing options...
neilestrick Posted December 21, 2020 Report Share Posted December 21, 2020 Not good. National electric code says that kilns must be on a circuit that is 25% greater than the draw of the kiln. So 28 amps goes to 35, and then you just go up to the closest actual breaker size, which would be a 40. At some point there's a good chance that you'll trip the 30 amp breaker, especially if you get new elements. You'll also be putting a lot of strain on the outlet, wires, and breaker since they're running continuously at close to their max allowable amperage. And if there's ever a fire due to the kiln, having it not wired up to code could be an issue with your insurance company. Why can't you change out the breaker? Many 18x18 interior kilns pull 24 amps, which requires a 30 amp breaker. Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 21, 2020 Author Report Share Posted December 21, 2020 17 minutes ago, neilestrick said: Not good. National electric code says that kilns must be on a circuit that is 25% greater than the draw of the kiln. So 28 amps goes to 35, and then you just go up to the closest actual breaker size, which would be a 40. At some point there's a good chance that you'll trip the 30 amp breaker, especially if you get new elements. You'll also be putting a lot of strain on the outlet, wires, and breaker since they're running continuously at close to their max allowable amperage. And if there's ever a fire due to the kiln, having it not wired up to code could be an issue with your insurance company. Why can't you change out the breaker? Many 18x18 interior kilns pull 24 amps, which requires a 30 amp breaker. I talked to my electrician about this and he seems relaxed about running the kiln on a 30 amp breaker, but i am not sure about it... He told me that there is no way to up the ampage of that since the location of the outlet and the central breaker box is too far that it will require major rennovation work.... I will take a look at 18x18 kiln then! thank u!! Link to comment Share on other sites More sharing options...
neilestrick Posted December 21, 2020 Report Share Posted December 21, 2020 Just now, grumpykidstudio said: I talked to my electrician about this and he seems relaxed about running the kiln on a 30 amp breaker, but i am not sure about it... If he knows that the 30 amp breaker is not up to code for that kiln and he's still okay with it, find another electrician. Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 21, 2020 Author Report Share Posted December 21, 2020 2 minutes ago, neilestrick said: If he knows that the 30 amp breaker is not up to code for that kiln and he's still okay with it, find another electrician. thank you for the advice!! I am looking into getting a 18x18 kiln now a holiday gift for myself! Link to comment Share on other sites More sharing options...
liambesaw Posted December 21, 2020 Report Share Posted December 21, 2020 From what I can tell, running close to capacity like that over time will wear out the breaker quickly. Not sure how dangerous it is, seems like it would perform it's major duty which is preventing overcurrent on the wires. The main danger would be if you went and flipped the breaker back on over and over. Right? The wire is still rated for 30 amps. Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 21, 2020 Author Report Share Posted December 21, 2020 2 minutes ago, liambesaw said: From what I can tell, running close to capacity like that over time will wear out the breaker quickly. Not sure how dangerous it is, seems like it would perform it's major duty which is preventing overcurrent on the wires. The main danger would be if you went and flipped the breaker back on over and over. Right? The wire is still rated for 30 amps. Hi Liam! Yah that is exactly what I am thinking rn... my option is either to spend a couple hundred bucks on fixing my current 28 amp kiln or spend some more on a smaller 24 amp kiln..... My current kiln is aboue 20-30 years old and I am not thinking to change the elements any time soon Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 22, 2020 Author Report Share Posted December 22, 2020 19 minutes ago, Rockhopper said: As Neil suggested - running just slightly below the rated capacity for an extended time can do more than cause the breaker to 'wear out quickly'. The witness cones in your kiln are melted by the combination of heat and time - the same can happen with your outlet, and the wires that run from the breaker to the outlet (as well as whatever materials that wire is running through/along inside the walls, between the breaker and the outlet). Will the breaker eventually trip ? Probably. Will it trip before any damage is done ? Maybe. Depends a little bit on how old everything is, what kind of breakers you have, and whether everything was installed properly to begin with. What about moving the kiln closer to the breaker box - or at-least to a location that would be more accessible to add a properly sized circuit ? Those are all amazing point! I am going to text my electrician to ask whether it is possible to upgrade the existing circuit to 35 amp! I cant really relocate my kiln cuz the garage is the only possible location for it the breaker is an extension from the outlet for the dryer, so hopefully the "upgrade" is possible! Link to comment Share on other sites More sharing options...
liambesaw Posted December 22, 2020 Report Share Posted December 22, 2020 19 minutes ago, Rockhopper said: As Neil suggested - running just slightly below the rated capacity for an extended time can do more than cause the breaker to 'wear out quickly'. So what can it do? Assuming the breaker is 30 amps, the kiln is 28, and the wiring is 10 gauge, which would be standard for 30 amps, what will the underrated breaker do other than wear out? I'm just curious, because the plug and wire catching fire would not be likely since the breaker is limiting to 30 amps. Link to comment Share on other sites More sharing options...
liambesaw Posted December 22, 2020 Report Share Posted December 22, 2020 2 minutes ago, grumpykidstudio said: Those are all amazing point! I am going to text my electrician to ask whether it is possible to upgrade the existing circuit to 35 amp! I cant really relocate my kiln cuz the garage is the only possible location for it the breaker is an extension from the outlet for the dryer, so hopefully the "upgrade" is possible! Oh yikes, definitely don't run a kiln on an extension cord. Link to comment Share on other sites More sharing options...
Mark C. Posted December 22, 2020 Report Share Posted December 22, 2020 Many electricans do not get the fact that kilns run at full amps for long periods 35 amps is not an option wire comes in #10 for 30 amps or #8 for 40 amps no number 35 amp wire size. You need a new wire run and breaker for this to be safe. Depending on the breaker is a bad idea. That is why the electrical code specifes the 25% rule. If you are spending the money just go to a #6 wire for the day you get a 60 amp kiln. The labor is the same and the wire is not that much more. Besides this all sounds right up there to keep you grumpy Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 22, 2020 Author Report Share Posted December 22, 2020 10 minutes ago, liambesaw said: Oh yikes, definitely don't run a kiln on an extension cord. Oh no it is not on an extension cord! but sharing the same outlet as the dryer is what i meant haha Link to comment Share on other sites More sharing options...
grumpykidstudio Posted December 22, 2020 Author Report Share Posted December 22, 2020 12 minutes ago, Mark C. said: Many electricans do not get the fact that kilns run at full amps for long periods 35 amps is not an option wire comes in #10 for 30 amps or #8 for 40 amps no number 35 amp wire size. You need a new wire run and breaker fir this to be safe. Depending on the breaker is a bad idea. That is why the electrical code specifes the 25% rule. If you are spending the money just go to a #6 wire for the day you get a 60 amp kiln. The labor is the same and the wire is not that much more. Besides this all sounds right up there to keep you grumpy that is a good point! I will try to keep my moods up once i sort this kiln situation out haha Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 22, 2020 Report Share Posted December 22, 2020 57 minutes ago, liambesaw said: So what can it do? Assuming the breaker is 30 amps, the kiln is 28, and the wiring is 10 gauge, which would be standard for 30 amps, what will the underrated breaker do other than wear out? I'm just curious, because the plug and wire catching fire would not be likely since the breaker is limiting to 30 amps. The 125% rule or 80% load rule is based on a continuous load that operates for three hours or more. Most automatic kilns never really do this but that said could so we treat them as such. This rule was put in place to protect the breaker itself from heating effect and then not tripping at the appropriate rating. So in the case of a breaker heated beyond a certain amount it might trip at a higher amperage than its rating. Most household breakers carry this 80% certification. Unfortunately 100% breakers start at 100 amps and to my knowledge are not made for smaller home loads yet. Link to comment Share on other sites More sharing options...
liambesaw Posted December 22, 2020 Report Share Posted December 22, 2020 Thank you @Bill Kielb, exactly what I wanted to know! And yeah it wouldn't be normal, unless your elements are shot and you're trying to get one last glaze firing.... Then they're continuous for like 6 hours haha Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 22, 2020 Report Share Posted December 22, 2020 6 minutes ago, liambesaw said: Then they're continuous for like 6 hours haha The interesting pointless point here is by the time the kiln gets to this point it consumes 10-15% less watts because of element wear and might comply. Go figure! Link to comment Share on other sites More sharing options...
Mark C. Posted December 24, 2020 Report Share Posted December 24, 2020 In regards to wire size you can run a larger wire then use the smaller beaker as that will protect the wire-so run the #6 and use a 40 amp breaker then someday you may get a 48amp kiln and you switch out the breaker to a 60 amp breaker. This is the best practice for wiring. Link to comment Share on other sites More sharing options...
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