Pottery Kilns tripping breakers
- Thread starter mark the sparky
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brian john
Senior Member
- Location
- Leesburg, VA
Re: Pottery Kilns tripping breakers
First I’d do a FOP across the CB at full load, do a comparison with the other kiln CB’s to get a relative acceptable Millivolt reading.
Second in lieu of the above an IR scan or in this case a non-contact temp. sensor is all that is required.
Second I’d question the circuit breaker, Put the CB on a high current test set and test it. Or swap CB’s with a CB from another kiln.
Third I would question as Bennie did the location to the Panel is the conductor heating or is the ambient around the panel increasing when this kiln is on line.
Fourth what is the full load current when the kiln is on line and how long is the unit on line before the CB trips?
Fifth what is the voltage at the terminal of the unit when running at full load?
Sixth is this CB located above the other kiln CB’s and is their heating affecting the long time trip of this CB or is this CB located between other high load CB, could be a 20 amp CB with 16 amps of load. Or possible the feeder connector termination heating.
It is either the load, defective CB or temperature related; from what you said I assume this to be a longtime issue with a thermal magnetic CB?
First I’d do a FOP across the CB at full load, do a comparison with the other kiln CB’s to get a relative acceptable Millivolt reading.
Second in lieu of the above an IR scan or in this case a non-contact temp. sensor is all that is required.
Second I’d question the circuit breaker, Put the CB on a high current test set and test it. Or swap CB’s with a CB from another kiln.
Third I would question as Bennie did the location to the Panel is the conductor heating or is the ambient around the panel increasing when this kiln is on line.
Fourth what is the full load current when the kiln is on line and how long is the unit on line before the CB trips?
Fifth what is the voltage at the terminal of the unit when running at full load?
Sixth is this CB located above the other kiln CB’s and is their heating affecting the long time trip of this CB or is this CB located between other high load CB, could be a 20 amp CB with 16 amps of load. Or possible the feeder connector termination heating.
It is either the load, defective CB or temperature related; from what you said I assume this to be a longtime issue with a thermal magnetic CB?
mark the sparky
Member
Re: Pottery Kilns tripping breakers
Charlie B...about those two nukes....missed me...and my neighbor is ticked...now we know who to bill!
2nd...you sound like a real estate broker...location, location, location...it's all about location with you guys (kidding) Actually that's not it either...tried changing positions for phasing and heating purposes..no change...plus it was athe Problem child in the old panel too.
3rd (to your forth)the kiln is fine for the first 8 hours of the cycle...then it hits "high" to fire the pottery with "all hell" and it cuts out sometime in the night...nobody knows when. We just find the tripped breaker in the AM and the pots are not fired completely...and then "all hell" does break out for me!!!
4th...not too sure about voltage at high cycle...not there at 12 AM to measure it when it kicks in. But I did bring up the point too the the area (it's a comercial location) may in fact experience a voltage drop on the grid...if other plants in the area are on a Startup mode or shift change.
5th...don't know...will probably test out the system wiht a recorder and see what takes place when the "cat's away".
Guys...the input is valuable...keep it coming. Thanks, and Charlie, my neighbor whats your address!
Charlie B...about those two nukes....missed me...and my neighbor is ticked...now we know who to bill!
1st (to your second) Not the breaker...have switched them a number of times.
2nd...you sound like a real estate broker...location, location, location...it's all about location with you guys (kidding) Actually that's not it either...tried changing positions for phasing and heating purposes..no change...plus it was athe Problem child in the old panel too.
3rd (to your forth)the kiln is fine for the first 8 hours of the cycle...then it hits "high" to fire the pottery with "all hell" and it cuts out sometime in the night...nobody knows when. We just find the tripped breaker in the AM and the pots are not fired completely...and then "all hell" does break out for me!!!
4th...not too sure about voltage at high cycle...not there at 12 AM to measure it when it kicks in. But I did bring up the point too the the area (it's a comercial location) may in fact experience a voltage drop on the grid...if other plants in the area are on a Startup mode or shift change.
5th...don't know...will probably test out the system wiht a recorder and see what takes place when the "cat's away".
Guys...the input is valuable...keep it coming. Thanks, and Charlie, my neighbor whats your address!
Re: Pottery Kilns tripping breakers
I installed a new Siemans 200 amp panel on my home. The main breaker or breakers are 4, 100 amp single pole breakers. 2 each are in parallel.
I asked the Siemans rep "why parallel 2, 100 amp breakers"? His answer is; (the problem being encountered with the kilns), "heat".
A 200 amp load across one pole, will create a lot more concentrated heat than 100 amps across 2 poles.
I installed a new Siemans 200 amp panel on my home. The main breaker or breakers are 4, 100 amp single pole breakers. 2 each are in parallel.
I asked the Siemans rep "why parallel 2, 100 amp breakers"? His answer is; (the problem being encountered with the kilns), "heat".
A 200 amp load across one pole, will create a lot more concentrated heat than 100 amps across 2 poles.
Re: Pottery Kilns tripping breakers
On the original post, it was noted that ( item 3 ) the kiln just had new heating elements.
Is the elements the correct ones for the voltage being used?
Have only worked on 1? 230 volt kilns, usually the the range of the name plate is. 230V, 45A, 10350W.
If these kilns are actually on 3?, are they wired, say, as 2 elements on A-B, 2 elements on B-C and 2 elements on C-A, or are the elements Line to neutral connected ?
I really suspect that the problem is the element is the wrong size or they are wired wrong .
Are these kilns elements automatic controled, ie. turning on by electronic or timers, or are the elements switched on manually in succession ?
Is it possible that toward the end on the heating cycle, that say, 3 elements are switched on C-A while the other phases just have two elements for loads ?
On the original post, it was noted that ( item 3 ) the kiln just had new heating elements.
Is the elements the correct ones for the voltage being used?
Have only worked on 1? 230 volt kilns, usually the the range of the name plate is. 230V, 45A, 10350W.
If these kilns are actually on 3?, are they wired, say, as 2 elements on A-B, 2 elements on B-C and 2 elements on C-A, or are the elements Line to neutral connected ?
I really suspect that the problem is the element is the wrong size or they are wired wrong .
Are these kilns elements automatic controled, ie. turning on by electronic or timers, or are the elements switched on manually in succession ?
Is it possible that toward the end on the heating cycle, that say, 3 elements are switched on C-A while the other phases just have two elements for loads ?
mark the sparky
Member
Re: Pottery Kilns tripping breakers
GWZ2...that is exactly what we have...single phase 230 volt kilns on 3 phase 208. But again, why are the other kilns not tripping the breaker?
These kilns are controlled by timers...and thermostats...I guess a low start cycle...medium mid cycle and a high end cycle.
They originally had a buck boost on it and took it off (I know...we went backwards) but again, the other kilns don't have buck boosts either.
GWZ2...that is exactly what we have...single phase 230 volt kilns on 3 phase 208. But again, why are the other kilns not tripping the breaker?
These kilns are controlled by timers...and thermostats...I guess a low start cycle...medium mid cycle and a high end cycle.
They originally had a buck boost on it and took it off (I know...we went backwards) but again, the other kilns don't have buck boosts either.
Re: Pottery Kilns tripping breakers
The installing is apparently using 1? 208 volts for each kiln.
Using the DC ohms law let's get some "Ball Park" values.
E * I = W
E / I + R (ohms)
E / R = I
These are actual values label on a 1? kiln.
Not all kilns will have the same values.
E * I = W
230V, 45A, 10350W
E / I = R
230V / 45A = 5.111111 ohms
for kiln on 230V
Now, same kiln on 208V,
E / R = I
208V / 5.1111111R = 40.695652 Amps
for kiln on 208V.
*********
Just what Amperage do each of the kilns draw ?
What is the actual voltage at each kiln ?
Still, apprears that one, or even all, of the kilns have had the elememts re-placed at some time, but were the proper element used for the voltage applied ?
Bennie had a good thought on the positon of the CB being heated by the other CB,s in the panelboard, but you said you changed locations of the loads.
Did you pull the Whole DP CB and re-locate the loads on the bus ? Thus still using the same DP CB for that kiln ?
The installing is apparently using 1? 208 volts for each kiln.
Using the DC ohms law let's get some "Ball Park" values.
E * I = W
E / I + R (ohms)
E / R = I
These are actual values label on a 1? kiln.
Not all kilns will have the same values.
E * I = W
230V, 45A, 10350W
E / I = R
230V / 45A = 5.111111 ohms
for kiln on 230V
Now, same kiln on 208V,
E / R = I
208V / 5.1111111R = 40.695652 Amps
for kiln on 208V.
*********
Just what Amperage do each of the kilns draw ?
What is the actual voltage at each kiln ?
Still, apprears that one, or even all, of the kilns have had the elememts re-placed at some time, but were the proper element used for the voltage applied ?
Bennie had a good thought on the positon of the CB being heated by the other CB,s in the panelboard, but you said you changed locations of the loads.
Did you pull the Whole DP CB and re-locate the loads on the bus ? Thus still using the same DP CB for that kiln ?
brian john
Senior Member
- Location
- Leesburg, VA
Re: Pottery Kilns tripping breakers
Ih this case were talking pure resistance, and all other factors have been checked, ambient is ok, CB is OK, FOP is acceptable, then it's gotta be AMPS..................
Ih this case were talking pure resistance, and all other factors have been checked, ambient is ok, CB is OK, FOP is acceptable, then it's gotta be AMPS..................
Re: Pottery Kilns tripping breakers
After reading the voltage 208 instead of 240, I know what is wrong. 208 volts suck.
This kiln six feet from the panel, operating with 208 volts will be on for a longer time, than it would on 240 volts.
This extended time creates heat with no time to cool off, like it would on 240 volts.
After reading the voltage 208 instead of 240, I know what is wrong. 208 volts suck.
This kiln six feet from the panel, operating with 208 volts will be on for a longer time, than it would on 240 volts.
This extended time creates heat with no time to cool off, like it would on 240 volts.
Re: Pottery Kilns tripping breakers
Time of the heating cycle for the 208 could easily have bearing as per Bennie.
With the proper heating element(s) installed, the 208V supply should be OK.
For the Kiln size 24" round by 36" depth which has 5 heating elements, that I know of, the 5.111111 ohm would be divided by the 5 elements would make the resistance of each element 1.022222 ohms for the 230V system.
For the 208 volt system, I would think the kiln, that I am using as an example, with 10350W @ 230V should also be 10350W for the 208V.
Let ^ = "Squared" for the following formula.
E^ / W = R
208V * 208V / 10350W = R
43264 / 10350 = 4.1800966 ohms
4.1800966 / 5 elements = 0.8360193 ohms for each element.
For the 208V system, now the Amperage would be
E / R = I
208 / 4.1800966 = 49.759615 Amps
Almost 5 Amps more than the same "Wattage" rated kiln using 230V.
I' still of the impression the kilns have had the elements change with the incorrect sized elements.
Time of the heating cycle for the 208 could easily have bearing as per Bennie.
With the proper heating element(s) installed, the 208V supply should be OK.
For the Kiln size 24" round by 36" depth which has 5 heating elements, that I know of, the 5.111111 ohm would be divided by the 5 elements would make the resistance of each element 1.022222 ohms for the 230V system.
For the 208 volt system, I would think the kiln, that I am using as an example, with 10350W @ 230V should also be 10350W for the 208V.
Let ^ = "Squared" for the following formula.
E^ / W = R
208V * 208V / 10350W = R
43264 / 10350 = 4.1800966 ohms
4.1800966 / 5 elements = 0.8360193 ohms for each element.
For the 208V system, now the Amperage would be
E / R = I
208 / 4.1800966 = 49.759615 Amps
Almost 5 Amps more than the same "Wattage" rated kiln using 230V.
I' still of the impression the kilns have had the elements change with the incorrect sized elements.
brian john
Senior Member
- Location
- Leesburg, VA
Re: Pottery Kilns tripping breakers
Bennie: Your mixing apples and oranges, kilns heat, vacuums suck, my vacuum pump works on 208 and 240 with little noticeable difference. But than can a vacuum pump?
Bennie: Your mixing apples and oranges, kilns heat, vacuums suck, my vacuum pump works on 208 and 240 with little noticeable difference. But than can a vacuum pump?
jtb
Senior Member
- Location
- Pennsylvania
Re: Pottery Kilns tripping breakers
"Can a vacuum pump?"
Hmmmm....I seen a horsefly....
"Can a vacuum pump?"
Hmmmm....I seen a horsefly....
Re: Pottery Kilns tripping breakers
A resistance load is affected by a voltage change much more than an inductive load.
A heating element will remain on for a longer duration on 208 volts than on 240 volts to maintain the same temperature.
The breaker will cool down when the unit cycles on 240 volts. It will cook in its own ambient temperature when continously running on 208 volts.
A resistance load is affected by a voltage change much more than an inductive load.
A heating element will remain on for a longer duration on 208 volts than on 240 volts to maintain the same temperature.
The breaker will cool down when the unit cycles on 240 volts. It will cook in its own ambient temperature when continously running on 208 volts.
- Location
- Illinois
- Occupation
- retired electrician
Re: Pottery Kilns tripping breakers
Bennie,
Wouldn't the amount of heat produced at the breaker be 25% less with the 208 volt system than with the 240 volt system? Yes, it may be on longer, but unless there is some type of problem in the panel the breaker should not ever trip with a load of 80% or less than the breaker rating.
Don
Bennie,
Wouldn't the amount of heat produced at the breaker be 25% less with the 208 volt system than with the 240 volt system? Yes, it may be on longer, but unless there is some type of problem in the panel the breaker should not ever trip with a load of 80% or less than the breaker rating.
Don
Re: Pottery Kilns tripping breakers
The ability to dissipate heat is the major concern.
Heat is energy, it will continue to increase without a medium for dissipating.
A panel in a location where there is is no air flow, or in a high ambient temperature, will depart from expected performance.
The ability to dissipate heat is the major concern.
Heat is energy, it will continue to increase without a medium for dissipating.
A panel in a location where there is is no air flow, or in a high ambient temperature, will depart from expected performance.
Re: Pottery Kilns tripping breakers
An added thought...The law of thermodynamic equilibrium states that the temperature of the breaker will eventually reach the same temperature of the kiln, depending on amount and rate of heat dissipation.
This is the principal of operation of a motor overload thermal element and switch. When the bi-metal element reaches the maximum rated temperature of the motor, it will shut down.
[ July 04, 2003, 02:14 PM: Message edited by: bennie ]
An added thought...The law of thermodynamic equilibrium states that the temperature of the breaker will eventually reach the same temperature of the kiln, depending on amount and rate of heat dissipation.
This is the principal of operation of a motor overload thermal element and switch. When the bi-metal element reaches the maximum rated temperature of the motor, it will shut down.
[ July 04, 2003, 02:14 PM: Message edited by: bennie ]
Re: Pottery Kilns tripping breakers
Some of the " cones " that I am aware of for the Kiln-Sitter to disconnect the line voltage power to the kiln is a Square Bar ( approximately 1/8" square and 1" long ) that is placed between the Kiln-sitter triggering supports which extend from the mechanical contactor on the outside of the kiln to approximately 1-1/2" inside the kiln and the cone is set on these two supports with a trigger finger resting on top of the cone.
When the temperature with-in the kiln reaches the temperature of the cone rating, the cone sags and allows the trigger finger to lower about 1/8" thus tripping the mechanical contactor and shutting "off" the power to the kiln.
These cones come in numbered ratings with "022" being designed to sag at 1165?F, on up to cone "01" which sags at 2152F?. Number "1" sags at 2154F? on up to cone number "12" which sags at 2471?F.
I just can not believe that the CB supplying these "cones" would ever match those temperatures.
Usually the kilns using the "022" thru the "05" size cones are "on" for less than 3 hours to reach the temperature of the cone rating.
We have used many size "8" cones ( 2372?F ) which usually takes about 7 to 8 hours of firing for the inside of the kiln reach that temperature and for the "cone" to sag and trip the Kiln-sitter "off" when firing Porcelain Dolls. The larger amount of product in the kiln requires longer firing times.
I consider that temperature as " HOT ".
You don't want to touch the ouside of the kiln until it cools down which is about 4 more hours just to touch.
Some of the " cones " that I am aware of for the Kiln-Sitter to disconnect the line voltage power to the kiln is a Square Bar ( approximately 1/8" square and 1" long ) that is placed between the Kiln-sitter triggering supports which extend from the mechanical contactor on the outside of the kiln to approximately 1-1/2" inside the kiln and the cone is set on these two supports with a trigger finger resting on top of the cone.
When the temperature with-in the kiln reaches the temperature of the cone rating, the cone sags and allows the trigger finger to lower about 1/8" thus tripping the mechanical contactor and shutting "off" the power to the kiln.
These cones come in numbered ratings with "022" being designed to sag at 1165?F, on up to cone "01" which sags at 2152F?. Number "1" sags at 2154F? on up to cone number "12" which sags at 2471?F.
I just can not believe that the CB supplying these "cones" would ever match those temperatures.
Usually the kilns using the "022" thru the "05" size cones are "on" for less than 3 hours to reach the temperature of the cone rating.
We have used many size "8" cones ( 2372?F ) which usually takes about 7 to 8 hours of firing for the inside of the kiln reach that temperature and for the "cone" to sag and trip the Kiln-sitter "off" when firing Porcelain Dolls. The larger amount of product in the kiln requires longer firing times.
I consider that temperature as " HOT ".
You don't want to touch the ouside of the kiln until it cools down which is about 4 more hours just to touch.
Re: Pottery Kilns tripping breakers
The bi-metal strip only has to reach 280?F to deflect enough to initiate a trip.
The wiring for the kiln, 6 feet away, could easily heat the breaker that much, through conduction.
I'll bet if the circuit length is doubled, the breaker will hold.
The bi-metal strip only has to reach 280?F to deflect enough to initiate a trip.
The wiring for the kiln, 6 feet away, could easily heat the breaker that much, through conduction.
I'll bet if the circuit length is doubled, the breaker will hold.
Re: Pottery Kilns tripping breakers
The kilns that I have looked at come with an 8' Cord and Plug. The cord has " 2 - 6 / 1 - 8 / SRDT " printed on it.
I do not know what SRDT means, just guessing the S is Silicone and the R is Rubber. Have made many-many cone 8 firings over the past 30 years and have not had a problem with the supply feeder, the receptacle or the factory cord and plug.
Have changed many-many elements and factory installed "on - off" switches which are for each set of elements.
I am talking of "HOBBY" class kilns.
Depending on the kiln size, they usually range from one element to six elements in the kiln.
Thus, it is very easy to get elements which are not designed for "THAT" kiln.
If you know the voltage used, the number of elements and the total wattage (which is on the Name Plate ), the kiln manufacturer will tell you what elements to use.
The element comes a specific length with the terminal ends folded back to make( I suspect ) more contact surface at the termination point.
Again, without knowing the actual installation details, the ambient temperature could be a problem on any long term firings.
Knowing the following for EACH kiln would help in making a judgement:
Name Plate Data; Volts, Amperage, Wattage.
Actual voltage reading(s) of the supply, both at the OCPD and at the Kiln terminals. (or at least at the receptacle).
Acutal Amperage reading(s).
Acutal 'field installed' wiring sizes.
If using a Kiln-Sitter, the typical "cone" being used when the trouble appears.
Did not mention before, but the earlier method was to set three cones on a stand in front of a "port hole" to observe the cones occasionally.
One cone was of a less heat rating and one cone the desired heat rating and a third cone above the desired heat rating.
When observing the sagging of the "less" heat rating, you knew to check very often to see when the desired heat rating cone strated to sag and then "turn OFF the kiln". The third, higher rated cone was to check if an "Over Firing" occurred.
The kilns that I have looked at come with an 8' Cord and Plug. The cord has " 2 - 6 / 1 - 8 / SRDT " printed on it.
I do not know what SRDT means, just guessing the S is Silicone and the R is Rubber. Have made many-many cone 8 firings over the past 30 years and have not had a problem with the supply feeder, the receptacle or the factory cord and plug.
Have changed many-many elements and factory installed "on - off" switches which are for each set of elements.
I am talking of "HOBBY" class kilns.
Depending on the kiln size, they usually range from one element to six elements in the kiln.
Thus, it is very easy to get elements which are not designed for "THAT" kiln.
If you know the voltage used, the number of elements and the total wattage (which is on the Name Plate ), the kiln manufacturer will tell you what elements to use.
The element comes a specific length with the terminal ends folded back to make( I suspect ) more contact surface at the termination point.
Again, without knowing the actual installation details, the ambient temperature could be a problem on any long term firings.
Knowing the following for EACH kiln would help in making a judgement:
Name Plate Data; Volts, Amperage, Wattage.
Actual voltage reading(s) of the supply, both at the OCPD and at the Kiln terminals. (or at least at the receptacle).
Acutal Amperage reading(s).
Acutal 'field installed' wiring sizes.
If using a Kiln-Sitter, the typical "cone" being used when the trouble appears.
Did not mention before, but the earlier method was to set three cones on a stand in front of a "port hole" to observe the cones occasionally.
One cone was of a less heat rating and one cone the desired heat rating and a third cone above the desired heat rating.
When observing the sagging of the "less" heat rating, you knew to check very often to see when the desired heat rating cone strated to sag and then "turn OFF the kiln". The third, higher rated cone was to check if an "Over Firing" occurred.
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