# Power in house going off/on without tripping circuit breakers **URL:** \ **Category:** Factual Questions\ **Created:** [July 14, 2019, 10:27pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087 "2019-07-14T22:27:14Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Shawn1767](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)\ **Post date:** [July 14, 2019, 10:27pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/1 "2019-07-14T22:27:14Z")
A little background, then maybe someone can tell me what might be happening and potential courses of action. Barry (Hurricane) passed over within the last 48 hours. Friday night, our power flickered considerably before going out altogether around 3:30 am for an hour. Power to this neighborhood has been on fairly steadily since. However, last night, power went out to part of the house (Kitchen and upstairs bathroom maintained power). I checked the circuit breakers, none were tripped. Power came on to house before I got inside. Stayed on for an hour. Power went out again to sections of the house. Been going off and on like this all day now. Only kitchen and upstairs bathroom are unaffected. I’ve noticed that when the AC unit kicks on, the power returns and when it kicks off, the power goes out a few seconds later. I’m thinking the phenomenon is connected to the AC unit somehow. But why, when the ac unit comes on does power return? And when it goes off, the power goes off? ---
**Author:** ![Thin\_Ice](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@Thin\_Ice](https://boards.straightdope.com/u/Thin_Ice)\ **Post date:** [July 14, 2019, 11:16pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/2 "2019-07-14T23:16:15Z")
I’d say the wind from Barry has loosened one of the hot wires coming to your house. Call the power company and tell them one or more of your service wires may be loose. ---
**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:** [July 14, 2019, 11:24pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/3 "2019-07-14T23:24:04Z")
> [@Thin\_Ice](#): > > I’d say the wind from Barry has loosened one of the hot wires coming to your house. Or possibly the neutral. This is very dangerous. Get it fixed ASAP. This is the sort of problem that can easily burn your house down. ---
**Author:** ![Thin\_Ice](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@Thin\_Ice](https://boards.straightdope.com/u/Thin_Ice)\ **Post date:** [July 14, 2019, 11:30pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/4 "2019-07-14T23:30:13Z")
If it was the neutral then all the power would go out. ---
**Author:** ![Shawn1767](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)\ **Post date:** [July 14, 2019, 11:44pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/5 "2019-07-14T23:44:19Z")
I called the power company. They’re sending someone over. It’s just really weird to me that the AC is basically controlling when the power is off or on. And that it corresponds to it being on/on or off/off. ---
**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:** [July 15, 2019, 12:01am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/6 "2019-07-15T00:01:38Z")
> [@Thin\_Ice](#): > > If it was the neutral then all the power would go out. Not necessarily. Google “floating neutral”. My thought is either a floating neutral that is being balanced out by the AC kicking on, or there is a loose connection in one of the hots that the electricity is managing to punch through the bad spot when there is a high enough current flowing. Either situation is bad and either one can result in a nasty fire. ---
**Author:** ![Shawn1767](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)\ **Post date:** [July 15, 2019, 1:25am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/7 "2019-07-15T01:25:52Z")
Power people came out. Said voltage to the house was good. Said to call electrician in the morning. ---
**Author:** ![HeiLo](https://avatars.discourse-cdn.com/v4/letter/h/c77e96/32.png) [@HeiLo](https://boards.straightdope.com/u/HeiLo)\ **Post date:** [July 15, 2019, 6:22am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/8 "2019-07-15T06:22:51Z")
> [@Shawn1767](#): > > It’s just really weird to me that the AC is basically controlling when the power is off or on. And that it corresponds to it being on/on or off/off. Are you sure that to have got the causation the right way around? Couldn’t it be that the A/C turns on when the power comes back, and turns off when the voltage drops/power goes out? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [July 15, 2019, 8:55pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/9 "2019-07-15T20:55:26Z")
Next time it goes out, check the breaker box and note which circuitds are out & which still working. If the working ones are all on one side of the power (all even-numbered or odd-numbered breakers) then it’s probably dead hot, like Yhin Ice said. Normally this happens outside, in the power company wires that are exposed to the weather, but it could happen in your inside wiring. Give your notes on which breakers work/don’t work to the electrician when he arrives. Which should be soon! ---
**Author:** ![Shawn1767](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)\ **Post date:** [July 16, 2019, 4:13am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/10 "2019-07-16T04:13:46Z")
I know I have the causation right because I can control the power by controlling the AC. If I want the power on, I turn on the AC and, voila, the power immediately comes on. If I turn off the AC, the power stays on for about 5 minutes, then goes out. I’ve repeated this method several times now. Btw, none of the breakers are ever tripped. Anyway, the electrician said it might’ve been a bad breaker. So he replaced the main breaker. The power still freaks out when the AC kicks off or on, but it hasn’t gone out all the way again yet. ---
**Author:** ![Shawn1767](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Shawn1767](https://boards.straightdope.com/u/Shawn1767)\ **Post date:** [July 16, 2019, 4:22am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/11 "2019-07-16T04:22:55Z")
And I just jinxed myself because it just happened again. AC cut off, followed by the power going out. Electrician said it might be something on the power company ‘s end. Regardless, it’s annoying. Because both the electrician and the power company came out today and said everything was ok. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [July 16, 2019, 4:31am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/12 "2019-07-16T04:31:14Z")
Do any other 240V appliances (electric stove or dryer) act like the AC in making the electricity work? That’s a strong indication of a ‘floating neutral’ problem. ---
**Author:** ![anomalous1](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@anomalous1](https://boards.straightdope.com/u/anomalous1)\ **Post date:** [July 16, 2019, 7:43am UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/13 "2019-07-16T07:43:44Z")
Check the conduit outside and the line and breaker feeding the AC unit for damage or the actual AC unit itself. Had a similar situation with an AC unit failing at a previous residence, it was damaged internally as well as being wired incorrectly (some d-bag had it buried in MC cable and it had a mysterious shared neutral at the panel to boot!). When it would go out, it would cut power to a bunch of different rooms, but no breaker would trip. Maybe there is just enough resistance or load that it hit that really scary and special sweet spot where the breaker doesn’t trip when it’s supposed to. It also led to the discovery of a whole host of bad wiring practices elsewhere in the house. Got it all fixed in one go, so I can’t definitively say the same is happening, just very familiar so I thought I’d share my anecdote. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 16, 2019, 3:02pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/14 "2019-07-16T15:02:00Z")
> [@engineer\_comp\_geek](#): > > … there is a loose connection in one of the hots that the electricity is managing to punch through the bad spot when there is a high enough current flowing. Yea, I’ve seen this happen before. There’s a “bad connection” on one of the hot legs, where “bad connection” is defined as “too much contact resistance.” When there is a light load, the contact resistance is high, resulting in a load voltage that’s low. Things won’t power up. But when the load is heavy, e.g. the air conditioning is on or the range is on, the contact resistance of the “bad connection” can actually decrease and things will operate normally. Why would this happen? Because under a heavy load, the temperature of the “bad connection” will get so high that the metals in the connection (copper and/or aluminum) will soften, resulting in larger A-spots and thus _less_ contact resistance. When the heavy load is turned off, the bad connection cools off, the area of the A-spots decreases, and the contact resistance of the bad connection is high again. I’m not saying this is what’s going on. Just a possibility. ---
**Author:** ![Thin\_Ice](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@Thin\_Ice](https://boards.straightdope.com/u/Thin_Ice)\ **Post date:** [July 22, 2019, 12:51pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/15 "2019-07-22T12:51:36Z")
So Shawn1767, did you ever find out what the problem was with your power? ---
**Author:** ![ishamael69](https://avatars.discourse-cdn.com/v4/letter/i/b9e5f3/32.png) [@ishamael69](https://boards.straightdope.com/u/ishamael69)\ **Post date:** [July 23, 2019, 2:41pm UTC](https://boards.straightdope.com/t/power-in-house-going-off-on-without-tripping-circuit-breakers/837087/16 "2019-07-23T14:41:46Z")
I’m curious too. I actually searched out this thread to see if there was an update.