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#1
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Floating neutral or wiring problem?
Last night several of the lights and outlets went dark in the house. Then
it mysteriously came back by itself for a few hours, and now these circuits went out again. All fuses tested ok (unless there is a failed circuit breaker somewhere). One of the dead circuits is an outlet that is right below the main panel (so it's not a fuse or breaker in a remote subpanel). Looking into this further, I tested the voltages going into a subpanel that is right next to the main panel. The difference between the two hot phases going into this subpanel show 110v. Between one of the hot phases and neutral it is 120v. Between the other hot phase and neutral it is only 12v! Last year the electric company came out to fix a broken neutral wire on the telephone pole, and this reminds me of the floating neutral problem I had back then, causing mysterious problems with some of the circuits. Because there is a major difference between the different phases and the neutral, I wonder if I should call out the electric company again, maybe their original repair failed? Or could this be due to a wiring problem inside the house that I should check first? Or perhaps a failed circuit breaker in this subpanel? |
#2
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Floating neutral or wiring problem?
On Mar 11, 7:06*pm, "scorpster" wrote:
Last night several of the lights and outlets went dark in the house. *Then it mysteriously came back by itself for a few hours, and now these circuits went out again. *All fuses tested ok (unless there is a failed circuit breaker somewhere). *One of the dead circuits is an outlet that is right below the main panel (so it's not a fuse or breaker in a remote subpanel).. Looking into this further, I tested the voltages going into a subpanel that is right next to the main panel. The difference between the two hot phases going into this subpanel show 110v. *Between one of the hot phases and neutral it is 120v. *Between the other hot phase and neutral it is only 12v! Last year the electric company came out to fix a broken neutral wire on the telephone pole, and this reminds me of the floating neutral problem I had back then, causing mysterious problems with some of the circuits. *Because there is a major difference between the different phases and the neutral, I wonder if I should call out the electric company again, maybe their original repair failed? Or could this be due to a wiring problem inside the house that I should check first? *Or perhaps a failed circuit breaker in this subpanel? Call the Electrc Co now , I would caution against using anything unless a V meter has pointed to show its ok, I had bad repairs on the electric co |
#3
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Floating neutral or wiring problem?
"scorpster" wrote in message ... Last night several of the lights and outlets went dark in the house. Then it mysteriously came back by itself for a few hours, and now these circuits went out again. All fuses tested ok (unless there is a failed circuit breaker somewhere). One of the dead circuits is an outlet that is right below the main panel (so it's not a fuse or breaker in a remote subpanel). Looking into this further, I tested the voltages going into a subpanel that is right next to the main panel. The difference between the two hot phases going into this subpanel show 110v. Between one of the hot phases and neutral it is 120v. Between the other hot phase and neutral it is only 12v! Last year the electric company came out to fix a broken neutral wire on the telephone pole, and this reminds me of the floating neutral problem I had back then, causing mysterious problems with some of the circuits. Because there is a major difference between the different phases and the neutral, I wonder if I should call out the electric company again, maybe their original repair failed? Or could this be due to a wiring problem inside the house that I should check first? Or perhaps a failed circuit breaker in this subpanel? If you test between the two hot legs, you should get 240 volts. If you test from each hot leg to neutral, you should get 120 volts. If you got 120 volts between the two hot legs, you have a dead leg. You need the check the breaker or fuses feeding that sub panel |
#4
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Floating neutral or wiring problem?
"RBM" wrote in message
... If you test between the two hot legs, you should get 240 volts. If you test from each hot leg to neutral, you should get 120 volts. If you got 120 volts between the two hot legs, you have a dead leg. You need the check the breaker or fuses feeding that sub panel All the 15A circuit fuses in the main panel check out ok when I test-replace them with a new fuse. I get 0.2 Ohms on the large 100A, and 40A fuses so they're fine too. So now I'm thinking maybe it's not a floating neutral, but rather it could be a dead leg on the phone pole? Maybe one of the hot legs could have broken on the phone pole from the swaying tree branches just like the neutral line connector broke last year.. would that be consistent with these symptoms? |
#5
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Floating neutral or wiring problem?
Just now I tested 8v at a 220v receptacle for the dryer.
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#6
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Floating neutral or wiring problem?
"scorpster" wrote in message ... "RBM" wrote in message ... If you test between the two hot legs, you should get 240 volts. If you test from each hot leg to neutral, you should get 120 volts. If you got 120 volts between the two hot legs, you have a dead leg. You need the check the breaker or fuses feeding that sub panel All the 15A circuit fuses in the main panel check out ok when I test-replace them with a new fuse. I get 0.2 Ohms on the large 100A, and 40A fuses so they're fine too. So now I'm thinking maybe it's not a floating neutral, but rather it could be a dead leg on the phone pole? Maybe one of the hot legs could have broken on the phone pole from the swaying tree branches just like the neutral line connector broke last year.. would that be consistent with these symptoms? You want to test at the main breaker, preferably with the main turned off. You have three legs coming in, 2 hot, 1 neutral. With the main breaker in the off position you should get 240 volts across the 2 hot legs, and 120 volts from each hot leg to neutral. If you don't get 240 across the 2 hot legs, one of them is dead |
#7
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Floating neutral or wiring problem?
Now after this next test I'm really puzzled. I checked the voltage at the
terminals where a door opens the circuit by pulling out the blades on two 100A fuses. This is the door that turns off power completely to the entire house. Between the top blade and ground it is 123V, and between the bottom blade and ground also 123V. When testing between both blade receptacles I would expect to see 240V, but instead it shows 0.2v, as if they're both in the same phase. |
#8
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Floating neutral or wiring problem?
On Mar 12, 1:47*am, "scorpster" wrote:
"Tony Hwang" wrote in message ... Hmmm, Your mistake was using that Fluke with too an input impedance. One reason I still often use Simpson 260. Some times El Cheapo analog meter is better in such as our case. Which readings would have most likely been different if I had used a better measuring device? *I thought the Fluke multi-meters were pretty good but it sounds like high voltage electrical is more tender. Even cheap (non-Fluke) volt meters are sensitive enough to pick up stray voltages, if you connect one side to ground and then touch your fingers to the input or + lead one will often pick up enough random electromagnetic radio and other electrical 'noise' to get small reading. And connect it to even dead wiring such a meter will often pick voltage from other working wiring running next to it within walls etc. Posters here have reported 'stray/random' but meaningless voltages up to 43 or more volts. A good choice for testing such a situation is a plain bulb. Or a pocket neon lamp/tester (Maybe that's what's called a wiggie?). A 230 bulb is best but a low wattage 115 volt can be used if just touched on wires for a moment. BTW I have a 230 volt low wattage bulb permanently mounted in my workshop which monitors the 230 volts; if one side were to go open the 115 volts from the oher ;side' would come through whatever 230 volt appliance happened to be on and that bulb would light more dimly than at 230 volts dimly. The single bulb is a better way to monitor the 230 volts than two bulbs one from each 'side or leg' to neutral. If one needed to test best way is to turn off main breaker and see what voltage is on the incoming wires ............. OR: Turn off all the individual circuit house breakers (every single one of them) and see what voltage there is on the output of the main breaker by testing the buss bars or inputs to the individual breakers. |
#9
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Floating neutral or wiring problem?
stan wrote:
On Mar 12, 12:53 am, "scorpster" wrote: Mystery solved! Southern CA Edison sent over a repair expert tonight within a couple hours. Turns out that one of the hot legs was broken at the telephone pole. The neighbor's tree branches are completely tangled around the wires, putting tension on the wires and causing the entire pole to tilt at an angle. This unraveled one of the hot wires. He repaired the connection, and he's sending a crew out within a week to trim the neighbor's trees, and then replace all the wires between the two poles, for a permanent fix. The best diagnostic clue that I found before he arrived was to measure between the two 100A fuses at the main panel, where this showed 0v instead of 240v. The reason I still got 123v from between each phase and ground, he explained, was because of back-feeding from the house circuits. Tip: keep your trees trimmed near the phone poles, and keep an eye on your neighbors trees! Exactly. One of the legs (sometimes but incorrectly called 'phases') was open. The two legs, with 230 volts between them are actually the two ends of a single 230 volt transformer winding; on the pole or underground etc. The middle or centre point of that winding is the zero or neutral point. A neighbour had the identical problem with the 230/115 volt service to his garage. Broken connection at the pole transformer. He couldn't figure why his 115 volt lights worked but nothing 230 volt would work! In non North American jurisdictions several actual 'phases' are sometimes brought into domestic/residences etc. In the Middle East my son had 230 volt 3 phase main circuit breaker panel in his 'villa'. In Malta the three phases and neutral (4 wires) went along the street on wall brackets and a different phase (and the neutral) were tapped into each house! And over in, for example, the UK everything is 230 volt; no 115 volt (except in certain special and unusual cases). Here, in Canada three wires come into house one being the neutral. The other two being the 230/115 volt legs as described by the OP. Hmmm, Pole? I don't see any pole in my neighborhood. Power, phone, cable, all are under ground. Nothing overhead. 4 wires, one is ground. |
#10
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Floating neutral or wiring problem?
scorpster wrote:
"The Daring Dufas" wrote in message ... Everyone should have a Wiggy. It needs no batteries and it's hard to break. http://tinyurl.com/clx8nz I might buy one from Amazon. So will this Wiggy really read the voltage differently than my Fluke? Under what conditions would Wiggy report a different voltage than a digital multimeter? This comes as quite a surprise to me that the trusty Fluke would be misleading under certain conditions. http://www.amazon.com/Klein-69115-So...8?ie=UTF8&s=hi The Wiggy is a low impedance device that actually puts a bit of a load on the circuit being tested. It's like a calibrated electromagnet. The higher the voltage, the harder the solenoid pulls against the spring and the farther the indicator moves. The Fluke meter will measure induced voltages on wiring that has very tiny current levels. The Wiggy won't react at all unless it's the type with an indicator light. You could hook some test leads to an electric hair clipper and get the same reaction. TDD |
#12
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Floating neutral or wiring problem?
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#13
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Floating neutral or wiring problem?
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#14
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Floating neutral or wiring problem?
Tony Hwang wrote:
The Daring Dufas wrote: wrote: On Wed, 11 Mar 2009 21:47:37 -0700, "scorpster" wrote: "Tony Hwang" wrote in message ... Hmmm, Your mistake was using that Fluke with too an input impedance. One reason I still often use Simpson 260. Some times El Cheapo anlog meter is better in such as our case. Which readings would have most likely been different if I had used a better measuring device? I thought the Fluke multimeters were pretty good but it sounds like high voltage electrical is more tender. Digital meters pick up capacitance, which is an induced low voltage across wires close to each other. They're made for working on electronics more than AC supply voltages. They're too sensitive to these oddball voltages like the 8 volts you saw at the dryer recp. If you get used to them, you ignore those small voltages. I much prefer a Wiggy as well as the cheap analog meters you can buy at places like Walmart for under $10. My digital meter is used for electronics only. However, you solved the problem, so be proud of your efforts. (Of course we all helped !!!! ). I'm glad we could help !!!! I also like to use my homemade testers. One is 2 lightbulbs wired in series (must be same wattage). They get dim on 110, bright on 220. I put aligator clips so I can hang them from wires and watch what they do as I work downstream. The other is a doorbell and transformer on a block of wood with a plug as well as aligator clips. With that I can make it buzz in a distant room and go to the breaker box and flip breakers and know which breaker controls that outlet or wires. A cheal plug in radio works too, but they dont always stay on the station and require antenna adjustments. I like the doorbell better. (for 110 ONLY). I often use the Jesus method for finding circuit breakers. I use a plug with a pair of #10 wires about a foot long with an inch of insulation stripped off. I plug it in and bring the bare ends of the wire together while turning my head to avoid looking at the bright flash and exclaim JESUS! after the mini explosion. It also tests the circuit breaker while making everyone around be very careful how they approach me because they now think I'm completely nuts. TDD Hmmm, When I was young I used to use my own two fingers, LOL! If you walked around giggling and twitching every time you used your fingers as a Bio-Wiggy, I suppose everyone would think you were completely bonkers too. TDD |
#15
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Floating neutral or wiring problem?
On Mar 12, 12:02*am, "scorpster" wrote:
"RBM" wrote in message ... I'll say it again. You need to check voltage across the main wires coming in. You want to test the wires before the fuses, not after the fuses, not at any outlet or dryer or range or anything else. If you don't have 240 volts across the two hot legs at the point that they come in, it's not an internal problem Indeed that was the best diagnostic clue, to measure the voltage at the hot legs before the fuses. *I bet that most people don't think to check that because it is not so common to have broken connections at the phone pole, and a lot more common to have blown fuses. I think you'd lose that bet. Given the symptoms you reported, it was very straightforward to work back to the incoming power line. *In this case turned out to be the neighbor's trees pulling on the phone pole wires, see my post below.... |
#16
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Floating neutral or wiring problem?
On Mar 12, 1:14*am, wrote:
On Wed, 11 Mar 2009 21:47:37 -0700, "scorpster" wrote: "Tony Hwang" wrote in message ... Hmmm, Your mistake was using that Fluke with too an input impedance. One reason I still often use Simpson 260. Some times El Cheapo anlog meter is better in such as our case. Which readings would have most likely been different if I had used a better measuring device? *I thought the Fluke multimeters were pretty good but it sounds like high voltage electrical is more tender. Digital meters pick up capacitance, which is an induced low voltage across wires close to each other. * They're made for working on electronics more than AC supply voltages. Capacitance is not an induced voltage. And there's no reason you can't use a digital VOM on AC. That's what I always use. *They're too sensitive to these oddball voltages like the 8 volts you saw at the dryer recp. *If you get used to them, you ignore those small voltages. Rather than ignore them, what you should have is an understanding of basic electricity so that you can correctly interpret what you are reading. As others have said, you can get a voltage reading with a digital unit because it has a high input impedance compared to a typical analog unit. Which means that it disturbs whatever it's measuring a lot less. The analog VOM actually loads down the line it's measuring enough that the 8 volts becomes .8, or whatever. You can turn the digital VOM into a less precise instrument if you want to by putting about a 1K resistor across it's terminals, effectively lowering it's input impedance. *I much prefer a Wiggy as well as the cheap analog meters you can buy at places like Walmart for under $10. *My digital meter is used for electronics only. However, you solved the problem, so be proud of your efforts. *(Of course we all helped !!!! ). *I'm glad we could help !!!! I also like to use my homemade testers. *One is 2 lightbulbs wired in series (must be same wattage). *They get dim on 110, bright on 220. *I put aligator clips so I can hang them from wires and watch what they do as I work downstream. *The other is a doorbell and transformer on a block of wood with a plug as well as aligator clips. *With that I can make it buzz in a distant room and go to the breaker box and flip breakers and know which breaker controls that outlet or wires. *A cheal plug in radio works too, but they dont always stay on the station and require antenna adjustments. *I like the doorbell better. (for 110 ONLY). |
#17
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Floating neutral or wiring problem?
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#18
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Floating neutral or wiring problem?
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#19
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Floating neutral or wiring problem?
HeyBub wrote:
.... who built up his tolerance to electricity. Over several months, starting with tiny batteries, he was able to withstand the maximum voltage to which he had access (440v I think). ... That's an utter fabrication if intended for other than the punch line. It ain't voltage that kills, it's current (roughly 15mA is sufficient through heart). Voltage is the driver behind current so it has an effect in making the likelihood of the current higher, but simply static voltage isn't a problem--think of the bird sitting on the HV transmission line. -- |
#20
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Floating neutral or wiring problem?
In article , wrote:
On Thu, 12 Mar 2009 05:43:18 -0700 (PDT), wrote: can turn the digital VOM into a less precise instrument if you want to by putting about a 1K resistor across it's terminals, effectively lowering it's input impedance. Wouldn't that resistor get hot pretty fast when across 110v or 220v? 1000-ohm resistor at 110 volts passes 110/1000 = 0.11 amps 0.11 amps at 110 volts = 12.1 watts Seems to me it would have to be a pretty large wattage resistor, not just a quarter or half watt one. And even a heavy duty 50W resistor would probably get hot enough to burn your skin really fast. Not if it's only dissipating 12 watts. |
#21
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Floating neutral or wiring problem?
On Mar 12, 1:35*pm, "HeyBub" wrote:
wrote: Wouldn't that resistor get hot pretty fast when across 110v or 220v? Seems to me it would have to be a pretty large wattage resistor, not just a quarter or half watt one. *And even a heavy duty 50W resistor would probably get hot enough to burn your skin really fast. Not if the resistance was quite high. If I = E/R where E=220 and R=(more zeros than the stimulus) the resulting I (current) is teeny. If R = (say) 220K, you get I = 220 / 220,000 = *1 ma. Power, then, is EI = 220 x .001 = .220 watts or 1/4 watt. Yes, you got me on that one guys. I didn't have my brain fully engaged. I was thinking more along the lines of the principle, which is you can turn a high impedance digital meter into a lower one by using a resistor in parallel. Something along the lines of 100K would work, which would give you 1/2 watt at 220V. I think I'd rather get a $10 cheap meter. *Besides that, a costly Fluke digital meter is too costly to use on a construction job where it will likely get dropped or worse. *I'd rather leave it on the bench, and use a cheap meter that wont make you cry if you drop it- Hide quoted text - - Show quoted text - |
#22
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Floating neutral or wiring problem?
dpb wrote:
HeyBub wrote: ... who built up his tolerance to electricity. Over several months, starting with tiny batteries, he was able to withstand the maximum voltage to which he had access (440v I think). ... That's an utter fabrication if intended for other than the punch line. It ain't voltage that kills, it's current (roughly 15mA is sufficient through heart). Voltage is the driver behind current so it has an effect in making the likelihood of the current higher, but simply static voltage isn't a problem--think of the bird sitting on the HV transmission line. -- Perhaps I can find a heart surgeon who will install a surge arrestor on my heart. TDD |
#23
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Floating neutral or wiring problem?
metspitzer wrote:
On Thu, 12 Mar 2009 12:29:38 -0500, "HeyBub" wrote: wrote: I knew a professional electrician who always used his fingers to test live wires. He had the best equipment, but yet he always did the finger mrthod. I never understood that, when a $3 neon tester can be clipped on your shirt pocket and always be handy. Later in life he developed heart problems, and after several open heart surgeries, it killed him. I always wonder if all those shocks were the reason? In a way. All those shocks over the years built up his resistance to electricity such that the defibrillators in the hospital had no effect. cite? Your body does not build up a resistance to electricity. Your hands can be dry and more fibrous which gives them more resistance, but this has nothing to do with "immunity" to electricity. You're probably right. There are people who have been exposed to lightning strikes which must be thousands of amps and dozens of kilovolts, while others have died handling batteries that go in watches. I suspect it's more of a genetic immunity than it is an acquired tolerance, possibly an evolutionary adaptation by carpet dwellers. Someone should look into this. |
#24
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Floating neutral or wiring problem?
On Thu, 12 Mar 2009 12:29:38 -0500, "HeyBub"
wrote: wrote: I knew a professional electrician who always used his fingers to test live wires. He had the best equipment, but yet he always did the finger mrthod. I never understood that, when a $3 neon tester can be clipped on your shirt pocket and always be handy. Later in life he developed heart problems, and after several open heart surgeries, it killed him. I always wonder if all those shocks were the reason? In a way. All those shocks over the years built up his resistance to electricity such that the defibrillators in the hospital had no effect. cite? Your body does not build up a resistance to electricity. Your hands can be dry and more fibrous which gives them more resistance, but this has nothing to do with "immunity" to electricity. |
#25
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Floating neutral or wiring problem?
On Mar 12, 12:02*am, "scorpster" wrote:
"RBM" wrote in message ... I'll say it again. You need to check voltage across the main wires coming in. You want to test the wires before the fuses, not after the fuses, not at any outlet or dryer or range or anything else. If you don't have 240 volts across the two hot legs at the point that they come in, it's not an internal problem Indeed that was the best diagnostic clue, to measure the voltage at the hot legs before the fuses. *I bet that most people don't think to check that because it is not so common to have broken connections at the phone pole, and a lot more common to have blown fuses. *In this case turned out to be the neighbor's trees pulling on the phone pole wires, see my post below.... Looking outside at the light pole my have been a good clue too. Jimmie |
#26
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Floating neutral or wiring problem?
"scorpster" wrote in message ... "Tony Hwang" wrote in message ... Hmmm, Your mistake was using that Fluke with too an input impedance. One reason I still often use Simpson 260. Some times El Cheapo anlog meter is better in such as our case. Which readings would have most likely been different if I had used a better measuring device? I thought the Fluke multimeters were pretty good but it sounds like high voltage electrical is more tender. Fluke makes excellent meters and test instruments. I have a couple at home and 3 differant types of testers at work. One is a very good modle 87 , one a simple digital volt and ohm meter with an amp probe, and one I like the best is really simple. It has several leds on it and tells if you have AC, Dc nad a very rough indication of the voltage,or low resistance in the circuit. I also use some of their high end (over $ 4000) calibration instruments. I deal with almost all kinds of industrial electricity. Everything from low voltage 4 to 20 miliamp signals to 480 volt 3 phase circuits at 500 amps or so. Also some 4160 volt circuits and while I have not done anything with it, we do have some 13,200 volt main feeders to deal with. YOu just have to know how and when to use the meters. For most simple AC problems I use the old Simpson 260. If I suspect a false reading due to induced voltage I change the scale and if the meter stays in about the same place , it is induced voltage. |
#27
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Floating neutral or wiring problem?
[snip]
I guess that's a way to kill 2 birds with one stone. Do your electrical work and pray at the same time. If by chance you get electrocuted, you'll go straight to heaven !!!! To get that to work, you need to learn to pray at precisely 77.7Hz (although some say 66.6Hz works just as well). [snip] |
#28
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Floating neutral or wiring problem?
Or could this be due to a wiring problem inside the house that I should check first? Or perhaps a failed circuit breaker in this subpanel? My neighbor had that problem in his 20 YO house.. One or more neutrals in his Service box were loose. He "lost" half of the appliances in his home: stove fridge and micro got "cooked". The "fix" was to tighten all the neutrals with a screwdriver |
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