# Puzzling electrical problem (North American outlets and plugs) **URL:** \ **Category:** Factual Questions\ **Created:** [May 27, 2011, 5:40am UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404 "2011-05-27T05:40:00Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [May 27, 2011, 5:40am UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/1 "2011-05-27T05:40:00Z")
_Just in case you are concerned, we are not using the outlets with the problem now until a professional electrician comes to work on the room, but I wonder how this weird issue could take place._ In a room that was not used often at the workplace, the outlets (North American standard) in 3 of the walls are not working properly, or poorly. It was not a big problem as the room was not used with electrical equipment until recently. We tested the light in the switch of a power strip, it looked dim in the 3 bad outlets, so the outlets were not used as devices did not turn on or they didn’t burst. Now there is one wall where the outlet did work… actually, it looked like it worked, the power light in the power strip turns on brightly, computers plugged to it do work, new digital projectors work, monitors work. But if one connects a set of speakers, with or without the surge protector/power strip, to that “good” outlet, then the speakers are toasted. Same with some fans, and in an old fashion overhead projector, the bulbs burst as soon the power switch was turn on. One possible clue is that the old over head projector’s instructions reported that the outlet should be grounded, otherwise the bulbs would burst. This issue was not found by all at the same time, different employees and assistants found the problem intermittently and with the room not used often, it was not until recently that a connection to one likely reason (bad wiring) was made. Still, it doesn’t explain to us why equipment with ground wire like computers continued to work, but other items with ground wire (like the old fashion overhead projector) did fail. And why other devices with no ground wire also popped and smoldered. What could be the most likely electrical problem? Yeah, it could be bad wiring, but I have trouble imagining the logic or possible reasons why some equipment did work and others didn’t. ---
**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:** [May 27, 2011, 5:47am UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/2 "2011-05-27T05:47:02Z")
Weak or open neutral. With out voltage readings that is just a SWAG. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [May 27, 2011, 9:53am UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/3 "2011-05-27T09:53:46Z")
Also, in the computers the ground is “extra safety” but not quite “required”. Sounds like for the projector it was an absolute requirement. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 27, 2011, 12:21pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/4 "2011-05-27T12:21:21Z")
all the outlets in the room have a problem. the room having bad wiring could behave like that, multiple circuits could be involved. things that didn’t die might have dual voltage inputs and could withstand the higher voltage that might be occurring which might be blowing other things up. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [May 27, 2011, 12:43pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/5 "2011-05-27T12:43:55Z")
[QUOTE=Snnipe 70E] Weak or open neutral. With out voltage readings that is just a SWAG. [/QUOTE] That’s my guess from afar as well. If the neutral is “loose” between two phases, one side may be delivering only 40 volts and the other side is getting 200 volts, for example. Modern computers can auto-sense the line voltage and cope with anything from 100 to 250 volts or so, but your projector and speakers were one-voltage critters that had no ability to handle excess voltage so they failed. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [May 27, 2011, 12:52pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/6 "2011-05-27T12:52:34Z")
> [@GIGObuster](#): > > \*J > In a room that was not used often at the workplace, the outlets (North American standard) in 3 of the walls are not working properly, or poorly. It was not a big pro > What could be the most likely electrical problem? Yeah, it could be bad wiring, but I have trouble imagining the logic or possible reasons why some equipment did work and others didn’t. NEMA standard 3 prong outlets require 3 conductor wiring from the power supply panel box. This provides ability for using ground fault interrupter circuit breaker type outlets also, a valuable personnel protection. Get a copy of the National Electrical Code book for details of all of the above. ---
**Author:** ![thelabdude](https://avatars.discourse-cdn.com/v4/letter/t/dc4da7/32.png) [@thelabdude](https://boards.straightdope.com/u/thelabdude)\ **Post date:** [May 27, 2011, 2:17pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/7 "2011-05-27T14:17:48Z")
I smell a shared neutral problem. You can wire up 2 circuits with the hots coming off opposite legs and sharing a single wire as a neutral. That wire carries the difference in amps between the 2 circuits. Add a bad connection or a few, and who knows what might happen. My guess it the the electronics are set up to detect incoming voltage and use either 120 or 230. Old stuff puts the higher voltage to bulbs and blows them. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [May 27, 2011, 2:32pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/8 "2011-05-27T14:32:10Z")
Thanks for the replies guys, I’m not familiar with electrical wiring so I was not sure what to look for. Looking around, the “open neutral” got me this: > **[Yahoo Search - Web Search](https://search.yahoo.com/)** > > The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web. > [@](#): > > An “open neutral” means that a receptacle is not connected to the grounded conductor of the circuit. This often happens when “back-stab” connections on receptacles are used, and the receptacles are not installed with a pig-tail, but are daisy-chained together. If the neutral (grounded) conductor comes loose from one, it will kill all of the “downstream” receptacles. > > This can be dangerous, if the circuit is part of a “multi-wire branch circuit”, where two ungrounded (hot) conductors share on neutral. In normal operation, the neutral carries only the “unbalanced” current from both circuits; generally, this is very little. When the neutral is dropped out of the equation, you suddenly have 240 volts on a 120 volt circuit. So a computer or monitor can deal with that, but other lesser electronics will be fried, a followup question: I would think that using that outlet even if computers can deal with it is not a good idea, am I wrong in assuming that even if items can work with that excess voltage that in the long run they are more likely to fail? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 27, 2011, 2:43pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/9 "2011-05-27T14:43:45Z")
> [@GIGObuster](#): > > So a computer or monitor can deal with that, but other lesser electronics will be fried, a followup question: I would think that using that outlet even if computers can deal with it is not a good idea, am I wrong in assuming that even if items can work with that excess voltage that in the long run they are more likely to fail? even if a device didn’t blow up instantly you would be putting it through wear and tear that might shorten its life. i would stop using all the outlets in the room. ---
**Author:** ![thelabdude](https://avatars.discourse-cdn.com/v4/letter/t/dc4da7/32.png) [@thelabdude](https://boards.straightdope.com/u/thelabdude)\ **Post date:** [May 27, 2011, 3:28pm UTC](https://boards.straightdope.com/t/puzzling-electrical-problem-north-american-outlets-and-plugs/583404/10 "2011-05-27T15:28:18Z")
Many devices are designed to run on either 120 or 230. They take what they get and do just fine as long as it is consistently one or the other. With flaky connections, the voltage could keep changing or be say 175 instead of either. Unplug stuff for the weekend and wait for the electrician.