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Post by the light works on Apr 18, 2024 4:28:19 GMT
My parents are having trouble with their stove. The voltage at the breaker is about 248V. Right where it should be. At the outlet, one leg is 128V, the other 40V, and the combined voltage is about 75V. So I replace the outlet. When I install it, voltage is 248V. Again, correct. However, when I plug the stove in, the stove won't work and the voltage is back to 75V when I check it. Am I missing something? clarify for me, please: is the voltage out of balance only while the stove is plugged in, or did you plug it in, try to get it to work, and then unplug it to test voltage? my next round of testing, would be to check voltage at the breaker with the stove plugged in and turned on. frequently a partial voltage drop like that is a sign of a corroded connection, and dropping under load and recovering without a load would confirm there is a point of high resistance in the weak leg. the challenge is in narrowing down where to look, hence checking voltage at the breaker while under load. if the breaker voltage is good while the stove receptacle voltage is bad, then you know it is in the wiring. otherwise, if the voltage is down at the breaker, you can continue upstream to the cables coming into the main lugs at the main panel - if the voltage is bad, there, it's time to call the power company. they have to pull the meter and load test at the meter. this will determine whether it is their problem or your problem. of course, a their problem result is the best case. if it's the wire to the stove, the next question would be if the kitchen has ever been remodeled. if so, there may be a junction box somewhere, and that would be the next likely culprit for a high resistance connection. otherwise, you may be needing to start looking for a damaged cable. |
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Post by the light works on Apr 18, 2024 4:31:06 GMT
My parents are having trouble with their stove. The voltage at the breaker is about 248V. Right where it should be. At the outlet, one leg is 128V, the other 40V, and the combined voltage is about 75V. So I replace the outlet. When I install it, voltage is 248V. Again, correct. However, when I plug the stove in, the stove won't work and the voltage is back to 75V when I check it. Am I missing something? There's a high resistance connection somewhere. Since you replaced the outet, we can rule that out. I doubt that there are any splices in the line that runs from the outlet to the breaker box so that only leaves the connections to the breaker or the breaker itself. Make sure the screws that hold down the wires on the breaker are tight and then, with the stove connected, check the voltage on each output lug of the breaker. If the voltage is low at that point, the breaker is the problem. If you remove the breaker to replace it, check the connections where the breaker latches on to the buss bars in the breaker box. Check for signs of corrosion or overheating. If the buss bars are corroded, you will need to clean that up before installing a new breaker. The buss bars have voltage on them so be sure to turn off the main breaker before touching either buss bar. if the bus bar is corroded, the only time I try to clean it up is if there is no extra space I can move the breaker to. trying to dress corroded busbars is a temporary fix at best. |
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Post by wvengineer on Apr 18, 2024 13:49:01 GMT
clarify for me, please: is the voltage out of balance only while the stove is plugged in, or did you plug it in, try to get it to work, and then unplug it to test voltage? my next round of testing, would be to check voltage at the breaker with the stove plugged in and turned on. frequently a partial voltage drop like that is a sign of a corroded connection, and dropping under load and recovering without a load would confirm there is a point of high resistance in the weak leg. the challenge is in narrowing down where to look, hence checking voltage at the breaker while under load. if the breaker voltage is good while the stove receptacle voltage is bad, then you know it is in the wiring. otherwise, if the voltage is down at the breaker, you can continue upstream to the cables coming into the main lugs at the main panel - if the voltage is bad, there, it's time to call the power company. they have to pull the meter and load test at the meter. this will determine whether it is their problem or your problem. of course, a their problem result is the best case. if it's the wire to the stove, the next question would be if the kitchen has ever been remodeled. if so, there may be a junction box somewhere, and that would be the next likely culprit for a high resistance connection. otherwise, you may be needing to start looking for a damaged cable. When I first replaced the outlet and turned on the breaker, I read ~240VAC red-black on the outlet with nothing plugged in. I plugged the stove in, it would not heat. The clock would start, but not the burners. When I unplug the stove, it then read 75VAC red-black. I would get this with and without the stove being plugged in. I would also get the same voltage reading at the terminals on the stove. I put this outlet in ~17 years ago. I believe it is a continuous run of wire to the breaker. I reliably get 240VAC on the terminals of the breaker, regardless if the stove is plugged in or not. |
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Post by ironhold on Apr 18, 2024 15:00:30 GMT
This might be a long shot, but check the stove itself to see if there's an issue with that.
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Post by the light works on Apr 18, 2024 15:17:49 GMT
clarify for me, please: is the voltage out of balance only while the stove is plugged in, or did you plug it in, try to get it to work, and then unplug it to test voltage? my next round of testing, would be to check voltage at the breaker with the stove plugged in and turned on. frequently a partial voltage drop like that is a sign of a corroded connection, and dropping under load and recovering without a load would confirm there is a point of high resistance in the weak leg. the challenge is in narrowing down where to look, hence checking voltage at the breaker while under load. if the breaker voltage is good while the stove receptacle voltage is bad, then you know it is in the wiring. otherwise, if the voltage is down at the breaker, you can continue upstream to the cables coming into the main lugs at the main panel - if the voltage is bad, there, it's time to call the power company. they have to pull the meter and load test at the meter. this will determine whether it is their problem or your problem. of course, a their problem result is the best case. if it's the wire to the stove, the next question would be if the kitchen has ever been remodeled. if so, there may be a junction box somewhere, and that would be the next likely culprit for a high resistance connection. otherwise, you may be needing to start looking for a damaged cable. When I first replaced the outlet and turned on the breaker, I read ~240VAC red-black on the outlet with nothing plugged in. I plugged the stove in, it would not heat. The clock would start, but not the burners. When I unplug the stove, it then read 75VAC red-black. I would get this with and without the stove being plugged in. I would also get the same voltage reading at the terminals on the stove. I put this outlet in ~17 years ago. I believe it is a continuous run of wire to the breaker. I reliably get 240VAC on the terminals of the breaker, regardless if the stove is plugged in or not. next step would be to check voltage on the actual wire in the breaker terminal, and the actual wire in the terminals of the receptacle. the receptacle connection should be good, since it is new, but it does eliminate the possibility of a bad connection. the same with the breaker terminals, you would think they would be good, but once in a while there is something wrong, and in fact, it may be that it was not tightened properly, worked loose, or developed a scale of corrosion that is blocking current flow. if it is aluminum wire, that makes the corrosion question more likely. my big concern right now, is that there is a connection or damaged wire that is in the process of burning out. and the wiggling involved with changing the outlet brought it back into contact, but as soon as load was placed on it, it burned further. once you eliminate the connections, my next step would be to pull out by cable length tester and measure from the bad leg to neutral from both ends. it's a capacitance meter, and would probably not give me a precise length to the fault, but it would at least give me a rough guess at where between the stove and the panel, to look for the fault. I.E. if it reads 20 feet from one side and 80 feet from the other, you can start looking 20% of the distance from the bad end. otherwise, visual inspection of everything you have access to. the redeeming thing about cable burnouts is they are usually visible, if they are someplace you can get eyes to them. |
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Post by GTCGreg on Apr 18, 2024 17:05:27 GMT
When I first replaced the outlet and turned on the breaker, I read ~240VAC red-black on the outlet with nothing plugged in. I plugged the stove in, it would not heat. The clock would start, but not the burners. When I unplug the stove, it then read 75VAC red-black. I would get this with and without the stove being plugged in. I would also get the same voltage reading at the terminals on the stove. I put this outlet in ~17 years ago. I believe it is a continuous run of wire to the breaker. I reliably get 240VAC on the terminals of the breaker, regardless if the stove is plugged in or not. next step would be to check voltage on the actual wire in the breaker terminal, and the actual wire in the terminals of the receptacle. the receptacle connection should be good, since it is new, but it does eliminate the possibility of a bad connection. the same with the breaker terminals, you would think they would be good, but once in a while there is something wrong, and in fact, it may be that it was not tightened properly, worked loose, or developed a scale of corrosion that is blocking current flow. if it is aluminum wire, that makes the corrosion question more likely. my big concern right now, is that there is a connection or damaged wire that is in the process of burning out. and the wiggling involved with changing the outlet brought it back into contact, but as soon as load was placed on it, it burned further. once you eliminate the connections, my next step would be to pull out by cable length tester and measure from the bad leg to neutral from both ends. it's a capacitance meter, and would probably not give me a precise length to the fault, but it would at least give me a rough guess at where between the stove and the panel, to look for the fault. I.E. if it reads 20 feet from one side and 80 feet from the other, you can start looking 20% of the distance from the bad end. otherwise, visual inspection of everything you have access to. the redeeming thing about cable burnouts is they are usually visible, if they are someplace you can get eyes to them. Spot on troubleshooting. You could make a career out of this. |
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Post by wvengineer on Apr 18, 2024 22:51:29 GMT
next step would be to check voltage on the actual wire in the breaker terminal, and the actual wire in the terminals of the receptacle. the receptacle connection should be good, since it is new, but it does eliminate the possibility of a bad connection. the same with the breaker terminals, you would think they would be good, but once in a while there is something wrong, and in fact, it may be that it was not tightened properly, worked loose, or developed a scale of corrosion that is blocking current flow. if it is aluminum wire, that makes the corrosion question more likely. my big concern right now, is that there is a connection or damaged wire that is in the process of burning out. and the wiggling involved with changing the outlet brought it back into contact, but as soon as load was placed on it, it burned further. once you eliminate the connections, my next step would be to pull out by cable length tester and measure from the bad leg to neutral from both ends. it's a capacitance meter, and would probably not give me a precise length to the fault, but it would at least give me a rough guess at where between the stove and the panel, to look for the fault. I.E. if it reads 20 feet from one side and 80 feet from the other, you can start looking 20% of the distance from the bad end. otherwise, visual inspection of everything you have access to. the redeeming thing about cable burnouts is they are usually visible, if they are someplace you can get eyes to them. I believe it is 6 ga aluminum. |
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Post by the light works on Apr 18, 2024 23:10:01 GMT
next step would be to check voltage on the actual wire in the breaker terminal, and the actual wire in the terminals of the receptacle. the receptacle connection should be good, since it is new, but it does eliminate the possibility of a bad connection. the same with the breaker terminals, you would think they would be good, but once in a while there is something wrong, and in fact, it may be that it was not tightened properly, worked loose, or developed a scale of corrosion that is blocking current flow. if it is aluminum wire, that makes the corrosion question more likely. my big concern right now, is that there is a connection or damaged wire that is in the process of burning out. and the wiggling involved with changing the outlet brought it back into contact, but as soon as load was placed on it, it burned further. once you eliminate the connections, my next step would be to pull out by cable length tester and measure from the bad leg to neutral from both ends. it's a capacitance meter, and would probably not give me a precise length to the fault, but it would at least give me a rough guess at where between the stove and the panel, to look for the fault. I.E. if it reads 20 feet from one side and 80 feet from the other, you can start looking 20% of the distance from the bad end. otherwise, visual inspection of everything you have access to. the redeeming thing about cable burnouts is they are usually visible, if they are someplace you can get eyes to them. I believe it is 6 ga aluminum. that means any place it is connected it could have corroded enough to break the connection - so if you haven't already, put a screwdriver on the breaker terminals ans see if they will tighten further. |
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Post by GTCGreg on Apr 19, 2024 2:09:53 GMT
I believe it is 6 ga aluminum. I'm sure that's your problem. Turn the stove breaker off and remove the wires. Clean them up really good with some emery cloth or wire brush and apply some of this stuff and then connect the wires back up making sure the screws are really tight. That should solve your problem. |
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Post by the light works on Apr 19, 2024 4:33:07 GMT
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Post by wvengineer on Apr 19, 2024 12:29:14 GMT
Let me talk to my mom. It's a short run of wire from the breaker to the outlet. I am half tempted to take out the wire all together and replace it with some 8 awg copper. (It's a 40 amp breaker.) Maybe replace the breaker as well, if I can find the correct one.
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Post by the light works on Apr 19, 2024 13:59:35 GMT
Let me talk to my mom. It's a short run of wire from the breaker to the outlet. I am half tempted to take out the wire all together and replace it with some 8 awg copper. (It's a 40 amp breaker.) Maybe replace the breaker as well, if I can find the correct one. if you have access to route a new wire, a new 8-3 cable, 4 pin receptacle, if it isn't already, and 4 wire cord, would bring the whole thing into the 21st century, if it's an antique breaker, that might be more of a challenge. |
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