Chris Campbell Posted June 8, 2014 Report Share Posted June 8, 2014 I have two Skutt 1227 kilns. They were professionally installed using the guidelines of the electrical requirements in the operating manual. They have 60 Amps breakers at the kiln where they can be shut off, and in the main panel in the house ( in image above the blue switches). The wire size is 6 and the run is about 30 feet long between kiln and main breaker. One kiln is drawing about 48 -50 and the other 50 - 51. It seems like we have done everything right, but the breaker in the house gets very hot. When we pulled it on Friday it was fried. We have also had issues with the breakers on the wall behind the kiln and have replaced those. So ... we are having the breakers in the house replaced but is there something else we should be checking?? I cannot believe the breakers should be getting that hot during firing especially since everything appears to be within specs. What are we missing?? Link to comment Share on other sites More sharing options...
Guest JBaymore Posted June 8, 2014 Report Share Posted June 8, 2014 It seems like we have done everything right, but the breaker in the house gets very hot. When we pulled it on Friday it was fried. We have also had issues with the breakers on the wall behind the kiln and have replaced those. What do you mean by "breakers in the house"? Are you talking about the main service breakers? Heat generation is the product of resistance to current flow. So something there is causing more resistance than should be there. It can be corrosion of connections (potentrially including the fixed type). It can be the wrong size supply wiring. (God forbid... it could be from aluminum wiring sometimes used in older places!!!) It can be wrong size breakers (internal current carrying capacity). Another potential factor can be that the heat being generated is "normal" (all circuits for evverything heat up a bit).... but that heat is being contained in an enclosure that was not designed for the capacity it is handling. And so it cannot dissapate the amount of heat energy being produced in a unit of time. If you are not only firing kilns (high continuious draw) but ALSO using other high capacity appliences that have breakers in the SAME box........ lots of heat being generated. The heat issue could also be environmental related. Installed in an area that is getting more heat energy from OTHER sources than the enclosure is designed for. Sun on exterior wall. Super insulation close up to the box. The box installed improperly. Hummmmmm............. box that is maximum 100 Amp..... with two 60 amp breakers? I'm not an electrician... but that seems weird. Even if the kilns are supposed to draw only 50 each. Aside from any "legality" question.... is that box OK for the heat generated by continuous use of 100 amps or maybe a TEENY bit more? I'd talk with your electrician about it. best, ....................john Link to comment Share on other sites More sharing options...
Mark C. Posted June 8, 2014 Report Share Posted June 8, 2014 I have a few questions I assume this has been set up like this for a long time and been fine?Years of firing? Your main service is a 200 amp yes?It looks like that. How often are you firing both at same time?Years of this? My 1227 is about 25 feet from main studio panel as your and has a sub panel as yours which its hard wired into. Over time my sub panel breaker cooked and almost caught fire I had to replace the panel and breakers -I posted that here two Januarys ago. By the way it was a Squre D like yours (I'm not a squre D fan now) Your main panel is not a square D those breakers are bryants or westinghouse Your sub panel is 100 amps max- see it says QO 100 amp max load center-so it's really overused when both kilns are on full.You are at maximum draw (actually a tad over 51+50=101) This may not be an issue unless you use these at the same time. This can be cured with a larger wire between sub and main panel The other thing is breakers over time as they are operating at max load will wear out The connections need to be super clean and some non oxidizer needs to be on the wire ends as well as torqued to specs (extrely tight) as any loosness will overheat them-one of these thigs is present I feel in your intallation and over time the breaker heats up. That load center will work fine as long as both kilns are not on full at same time if thats your main use then upsize that wire run one size. The breakers should not be heating up. Mark Link to comment Share on other sites More sharing options...
Chris Campbell Posted June 8, 2014 Author Report Share Posted June 8, 2014 >What do you mean by "breakers in the house"? Are you talking about the main service breakers? Yes, the main service breakers in the house and it is 200 Amps. The only breaker that gets hot is the kiln one and it gets so hot that it has also fried the one across the way from it. We have been opening the box to let circulating air in once we noticed the heat. >NEMA box that is maximum 100 Amp..... with two 60 amp breakers? Only one can be used at a time ... both kilns cannot be fired simultaneously. Link to comment Share on other sites More sharing options...
Guest JBaymore Posted June 8, 2014 Report Share Posted June 8, 2014 Mark (above) has you covered. best, ..................john Link to comment Share on other sites More sharing options...
Mark C. Posted June 8, 2014 Report Share Posted June 8, 2014 This is one of those issues that a few minutes of talking story equals tons of typing. I'll pm you my phone # I'm near the phone now and we can clear this up if you call me. Mark Link to comment Share on other sites More sharing options...
Wyndham Posted June 8, 2014 Report Share Posted June 8, 2014 I have had breakers go out.It seem that over time the current demand causes a heating issue. The heat seems to cause a loosening in the breaker contacts and more heat is generated and so on that over time the breaker can arc out before tripping the breaker. I maybe wrong but I think breakers are designed to trip on a power surge, not gradual deterioration. I have had this happen in an almost identical setup except it's in my studio(an old service station). I recently had a hot leg on the meter box out side that did the same thing. One person said it might be due to fluctuations in the power supplied by Duke energy, another said it's the kilns drawing power at high amps for extended periods of time that fatigue the contacts. My breakers get hot but not till they are about to go out. I replace them (60 amp) about every 5 years. Wyndham Link to comment Share on other sites More sharing options...
Mark C. Posted June 8, 2014 Report Share Posted June 8, 2014 (kilns drawing power at high amps for extended periods of time that fatigue the contacts.) This wears them out compared to your regualar 15 and 20 amps breakers) If you use your haevy amp stuff your breakers will also get used up over time. The breaker is made to trip before the wire catches fire from to much amp draw. Its a fire deal to protect the wires. Thats why under sizing breakers is fine (say a 40 amp breaker on a #6 wire ) but oversizing is not fine as the wire will fry and start a fire before breaker trips in say a #6 wire with a 80 amp breaker) Mark Link to comment Share on other sites More sharing options...
Chris Campbell Posted June 8, 2014 Author Report Share Posted June 8, 2014 Thanks Mark ... I had to go out and missed your message til now. The fatigue makes a great deal of sense especially since those breakers are close to twenty years old ... yikes. So hubs has gone out to buy new ones ... we will change them out and see if that solves the issue with the next firing. Another thought is that I always hold the kiln at high temp at the end of the firings and that must take its toll too. THANKS TO ALL WHO GAVE GOOD, SOLID INPUT. I will report back after the first firing ... sadly, probably not for months !!!! arggg ... this year is zooming by too quickly. Link to comment Share on other sites More sharing options...
Mark C. Posted June 8, 2014 Report Share Posted June 8, 2014 Chris You said (Only one can be used at a time ... both kilns cannot be fired simultaneously.) What keeps you from firing them both? does each kiln have a breaker at sub panel? also have your husband pick up some oxiguard to coat wires and really torque the screws when tightening Mark Link to comment Share on other sites More sharing options...
Guest JBaymore Posted June 8, 2014 Report Share Posted June 8, 2014 also have your husband pick up some oxiguard to coat wires and really torque the screws when tightening +1 Link to comment Share on other sites More sharing options...
Chris Campbell Posted June 8, 2014 Author Report Share Posted June 8, 2014 Thanks ... He already did the oxiguard and will tighten the crews as advised. Yes Mark, each kiln has it's own breaker at the box behind the kiln. I've never had the production schedule that needed both going at once. I've always had a couple days between. Link to comment Share on other sites More sharing options...
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