# Power Outage Question **URL:** \ **Category:** Factual Questions\ **Created:** [February 2, 2011, 6:57pm UTC](https://boards.straightdope.com/t/power-outage-question/569924 "2011-02-02T18:57:53Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [December 10, 2011, 5:47pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/21 "2011-12-10T17:47:01Z")
> [@Waffle\_Decider](#): > > Something similar is happening to me right now. I’m getting normal power on one circuit, but only about 60 - 70 V on the other circuit. I can mostly get by ok with the good circuit, but apparently this is not good enough for the water heater of my condo building. ☹ Still, I think I’m fortunate that I still have partial power. > > This seems to be a fairly common failure mode in my area. This has happened a few times before, both at home and at my former workplace. the 60 to 70vac reading is probably a feedback voltage from the 240 vac equipment like an electric water heater. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [December 10, 2011, 6:11pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/22 "2011-12-10T18:11:25Z")
> [@pbeardtn](#): > > I have another question for you - > > Anyway, ever since then our home had a flicker that is noticeable most of the time, but particularly in the winter - it drives me CRAZY! > > I have had several visits from the utility service and they say it is not their problem. They have checked the neutral bus, cleaned the connectors, put a machine called “the Beast” on the line, hook a monitoring computer to the house for 24 hours, and still nothing. Every lineman and supervisor has seen the flicker, but they declare my feed is uniform and constant. > > I have a friend who is an electrician and he has tested every circuit, outlet, switch, etc in the house. > > My other idea is that when I lost the neutral to my house it fried my breaker box, or at least a portion of it. They say it isn’t their problem. > > What do you think is going on? if the utility inspected and maintained there equipment and then monitored the power and they find the power within specifications then the problem is likely not theirs. how did the electrician test your house? put a voltage monitor long term at different locations in your house system, place different loads on it from various locations. correlate loads, voltage drops/loss and their locations in the system. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 10, 2011, 6:33pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/23 "2011-12-10T18:33:22Z")
> [@pbeardtn](#): > > FYI the fire marshal never changed his ruling. There’s not enough information there to draw any definite conclusions. A broken neutral will cause the neutral to float, so you’ll have 240 volts between the two hot lines, but the neutral will be anywhere in between, and will vary depending on the loads connected to the circuits. The line voltages relative to neutral could be split 60/180 or 100/140 or pretty much anyway that adds up to 240. Electronic devices and equipment on the line that drops will usually just stop working, though undervoltages can cause damage. Equipment on the line that rises though can very easily be damaged and cause a fire. That said, it’s not clear which is the cause and which is the effect. If the neutral broke first, it could have cause the HVAC to burn out. However, it’s also possible that the HVAC failed, and excessive current from it cause the neutral to break. Without more information, the fire marshall is probably going to stick by the original ruling. > [@pbeardtn](#): > > Anyway, ever since then our home had a flicker that is noticeable most of the time, but particularly in the winter - it drives me CRAZY! A certain amount of flickering is perfectly normal. The power company constantly monitors the lines and switches things on and off of it as needed. They may boost the voltage a bit if the loads on it cause it to drop. They will add and remove capacitors as necessary to correct what is known as the “power factor” (I can explain that more if you are curious, but it has to do with making the entire system more efficient). Also, since wires aren’t superconductors, any load on the line will tend to drag its voltage down a bit. The more loads on the line and the longer the line the more noticeable this will be. If your neighbor’s fridge kicks on, for example, you may see a bit of a flicker in your lights. Loads switched onto your local transformer (which probably feeds your house and maybe a couple of your neighbors) will make a more noticeable flicker, though loads anywhere on the power distribution network do have some effect. The real question is do you have a normal amount of flicker or is it really excessive, which I can’t answer from an SDMB post. Excessive flicker could be a sign of a bad connection somewhere. It sounds from your post like the power company has checked its side of things pretty thoroughly. You’d have to pay an electrician on your own nickel to check the wiring on your side of things. I doubt you have a bad transformer. Did the power company check your power at the breaker box? If so you can probably eliminate the underground line as well. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [December 12, 2011, 2:43pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/24 "2011-12-12T14:43:33Z")
> [@engineer\_comp\_geek](#): > > There’s not enough information there to draw any definite conclusions. A broken neutral will cause the neutral to float, so you’ll have 240 volts between the two hot lines, but the neutral will be anywhere in between, and will vary depending on the loads connected to the circuits. The line voltages relative to neutral could be split 60/180 or 100/140 or pretty much anyway that adds up to 240. Electronic devices and equipment on the line that drops will usually just stop working, though undervoltages can cause damage. Equipment on the line that rises though can very easily be damaged and cause a fire. > > That said, it’s not clear which is the cause and which is the effect. If the neutral broke first, it could have cause the HVAC to burn out. However, it’s also possible that the HVAC failed, and excessive current from it cause the neutral to break. > > Without more information, the fire marshall is probably going to stick by the original ruling. > > A certain amount of flickering is perfectly normal. The power company constantly monitors the lines and switches things on and off of it as needed. They may boost the voltage a bit if the loads on it cause it to drop. They will add and remove capacitors as necessary to correct what is known as the “power factor” (I can explain that more if you are curious, but it has to do with making the entire system more efficient). Also, since wires aren’t superconductors, any load on the line will tend to drag its voltage down a bit. The more loads on the line and the longer the line the more noticeable this will be. If your neighbor’s fridge kicks on, for example, you may see a bit of a flicker in your lights. Loads switched onto your local transformer (which probably feeds your house and maybe a couple of your neighbors) will make a more noticeable flicker, though loads anywhere on the power distribution network do have some effect. > > The real question is do you have a normal amount of flicker or is it really excessive, which I can’t answer from an SDMB post. Excessive flicker could be a sign of a bad connection somewhere. It sounds from your post like the power company has checked its side of things pretty thoroughly. You’d have to pay an electrician on your own nickel to check the wiring on your side of things. > > I doubt you have a bad transformer. Did the power company check your power at the breaker box? If so you can probably eliminate the underground line as well. True dat! Being an electrician myself, it’s often very hard to diagnose a “flicker”. Could be an anomalous surge on the line from the power company or your neighbor could have an enormous welder in his garage that he uses from time to time (being that you share the same transformer). Often it’s an overlooked corroded connection point or loose neutral somewhere in the system. ---
**Author:** ![JohnErin](https://avatars.discourse-cdn.com/v4/letter/j/90db22/32.png) [@JohnErin](https://boards.straightdope.com/u/JohnErin)\ **Post date:** [May 16, 2016, 6:13pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/25 "2016-05-16T18:13:32Z")
I have discovered that when one side of the house goes out, if I turn on any 240V appliance it triggers the outage to come back on. Thoughts?? ---
**Author:** ![Count\_Blucher](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@Count\_Blucher](https://boards.straightdope.com/u/Count_Blucher)\ **Post date:** [May 16, 2016, 6:21pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/26 "2016-05-16T18:21:36Z")
> [@JohnErin](#): > > I have discovered that when one side of the house goes out, if I turn on any 240V appliance it triggers the outage to come back on. Thoughts?? Do you mean it triggers the power to come back on or that it triggers all of the power to go off? Either way, from the pole to the house is your utility’s responsibility & you can call them 24-7 about that at no cost to you. Anything from that point to the breaker box (and beyond) is a job for an electrician, which a homeowner must pay for. Most people call the utility first to make sure it isn’t a job for an electrician. The Tech that comes on site will tell you which problem it is. ---
**Author:** ![JohnErin](https://avatars.discourse-cdn.com/v4/letter/j/90db22/32.png) [@JohnErin](https://boards.straightdope.com/u/JohnErin)\ **Post date:** [May 16, 2016, 6:38pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/27 "2016-05-16T18:38:06Z")
It turns the power back on. Utility have been to the house. Unfortunately, the power is on and fine when they are there. Thanks. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [May 16, 2016, 7:31pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/28 "2016-05-16T19:31:56Z")
> [@JohnErin](#): > > I have discovered that when one side of the house goes out, if I turn on any 240V appliance it triggers the outage to come back on. Thoughts?? My first thought is YOU ARE GOING TO BURN YOUR HOUSE DOWN. Seriously. Get this fixed ASAP!!! You’ve got a bad connection somewhere in one phase. Since it affects the entire phase, it’s either at the pole, in the meter, in the cutoff switch (if you have one) or in the breaker box itself. Or it could be a bad wire anywhere along that path. Since it is an intermittent connection, that connection is likely getting hot, even when it is “working”. GET IT FIXED NOW!!! As in pick up the phone and call an electrician as soon as you read this. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [May 17, 2016, 3:22am UTC](https://boards.straightdope.com/t/power-outage-question/569924/29 "2016-05-17T03:22:32Z")
John Erin is finding that his 240 volt appliance still operates when the mains supply is down a phase… This is to be expected where the 120 volt part of the 240 volt appliance is getting power … He should not operate 240 volt devices, and rush to turn them off, when there is a problem with one phase of the supply to his house. The use of transformers, for only a few residences, makes these sorts of issues far more common, because its easier for someone’s usage , eg perhaps turning on a large electric motor, can cause an issue with overload or something. That is because one users start up surge is easily up at the circuit breaker trip … Where as if the transformer supplied 100 residences, the turn on surge current from a few users is still not enough to trip the distribution systems breakers. I understand the use of the small transformers is to allow easy replacement of them to provide customised power … this place wants 240 volts, this place wants three phase… High power here, cheap wiring there … etc ---
**Author:** ![Count\_Blucher](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@Count\_Blucher](https://boards.straightdope.com/u/Count_Blucher)\ **Post date:** [May 17, 2016, 1:18pm UTC](https://boards.straightdope.com/t/power-outage-question/569924/30 "2016-05-17T13:18:35Z")
> [@engineer\_comp\_geek](#): > > GET IT FIXED NOW!!! As in pick up the phone and call an electrician as soon as you read this. Seconded. Cost of electrician vs cost of a house fire? Your home, and everything inside it, isn’t something you should gamble with. PS- The meter is the D-Mark. My answer was incomplete and **engineer\_comp\_geek**'s answer was better. Sometimes when a Tech goes out and sees a truly dangerous situation, they’ll turn off the meter and tag it with violations for the licensed electrician that the homeowner needs to hire to address. Once all the listed violations are fixed, the Utility will send someone out to inspect the repairs. The Tech will open the meter, turn it back on, and seal it with a normal operation tag. They do this for safety, not to punish you, because they don’t want your house to burn down either. [Previous page](https://boards.straightdope.com/t/power-outage-question/569924.md?page=1)