[SOLVED] Mains AC problems at home - Page 1
Forum section: electronics / general

author: 0xabe
author_rank: Newbie
timestamp: July 11, 2017, 11:13:02 pm
content: Hi everyone. I live in the USA and recently bought a new house. I had a security monitor plugged directly into the wall outlet. I then plugged a UPS battery backup into the wall (for my PC). Upon plugging the UPS in, the security monitor had rolling dark/light banding and the picture became distorted. The UPS had been unplugged for a few days so I assume it began drawing power to charge the battery.Later I did some vacuuming and the picture became totally distorted while the vacuum was running and the screen showed white and black static over what was supposed to be the picture. Now the picture constantly jumps around, stretches, and has permanent rolling light/dark banding. I have ruined other smaller electronics by running the vacuum as well.Since the monitor visually reacts to the vacuum, I have tried the vacuum on multiple outlets and in different rooms and I get the same erratic effects. I've never experienced this before and believe there is a problem with my electrical wiring. What's going on and how do I stop this? I can't help but wonder how far this noise is traveling and to what other electronics in the house.Thanks for your input.

author: Ampera
author_rank: Super Contributor
timestamp: July 12, 2017, 12:32:46 am
content: This sounds nuts. It doesn't surprise me because US houses are wired using nails and bailing wire, but I don't know what would cause this.

author: amyk
author_rank: Super Contributor
timestamp: July 12, 2017, 12:46:52 am
content: If you're causingpermanentdamage, I suspect overvoltage due to an open/loose neutral. If you can measure voltage safely, do so.

author: Unknown
author_rank: Unknown
timestamp: July 12, 2017, 02:26:39 am
content: If you don't have many tools to measure what is going on, these are some cheap ones that can reveal some common issues:Outlet testerVoltage tester$10 well spent even if you do have a more complex multimeter.

author: Nusa
author_rank: Super Contributor
timestamp: July 12, 2017, 02:46:23 am
content: When you say new house, do you actually mean new, or just new to you? When was it built? Are you the first occupant?QuoteCould you be more specific as to what died?But I agree, first thing is to test your electrical system for obvious faults. In the meantime, you may want to unplug anything you value before vacuuming.

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 12, 2017, 04:09:16 am
content: Sounds like you have an open or bad ground. Thus the surges from high current devices and motor spikes can't be filtered properly by surge suppressors that require ground.You should get a socket tester ASAP.EDIT: If you had an open neutral and seprate phase wiring, everything in your house would have already exploded from 240v going down a 120v system. However, alot of switching supplies nowadays are universal and wouldn't care.

author: sibeen
author_rank: Frequent Contributor
timestamp: July 12, 2017, 04:13:38 am
content: Unless youreallyknow what you are doing I'd advise getting a sparky in to check out the situation.

author: alm
author_rank: Super Contributor
timestamp: July 12, 2017, 04:34:34 am
content: I second that. This is a new (to 2750) house which might have all kind of hidden defects that could result in equipment damage, safety issues or even fire. Clearly there is something wrong, so I would have a professional electrician check out the installation to at least identify any issues.Depending on the details of US law, you might have a claim against the seller of the house for hidden defects. But you would definitely need a report from a professional electrician for that.

author: Nusa
author_rank: Super Contributor
timestamp: July 12, 2017, 05:07:18 am
content: Quote from: Cyberdragon on July 12, 2017, 04:09:16 amI disagree. A missing safety ground, by itself, wouldn't result in all the symptoms described. Things may be less safe, but generally everything will work as normal.A floating neutral, on the other hand, can result in wild voltage swings, depending on the loads on each phase, and whether the neutral is completely severed or still has an earth connection via grounding rods, other appliances, and/or the safety ground. Basically a big voltage divider if you can figure out the the resistances of everything connected.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 12, 2017, 07:15:34 am
content: Sounds like a crap monitor to me.The monitor will have an AC/DC power supply inside. This should be able to filter the noise a vacuum cleaner makes.However, it can't hurt having a electrician perform a safety and compliance check on your house.If it has major issues, you can sue the sellers.

author: 0xabe
author_rank: Newbie
timestamp: July 12, 2017, 04:02:42 pm
content: The house is new to me, originally built in 1993. I have a ground and outlet tester. It was showing normal outlets, however I noticed there was some slop in the connection and I could get an open neutral on several of the outlets in the circuit. On a hunch, I replaced 3 outlets and now things work great. I was also pleasantly surprised to discover that the monitor works great and wasn't damaged after all.Thanks for everyone's suggestions. I will try to mark this thread as solved.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 12, 2017, 07:10:59 pm
content: Did they use the push in connections rather than the screw lugs?

author: tooki
author_rank: Super Contributor
timestamp: July 12, 2017, 07:24:11 pm
content: Quote from: Paul Moir on July 12, 2017, 07:10:59 pmI think he means that the contacts in the sockets themselves loosened, such that inserted plugs no longer grip well. It's a common problem with cheap US sockets.

author: Nusa
author_rank: Super Contributor
timestamp: July 12, 2017, 08:05:02 pm
content: Quote from: tooki on July 12, 2017, 07:24:11 pmThey were presumably 25-year-old outlets. It's possible to wear them out in that time, especailly if in a high-use (many insertions/removals daily) or rough-use (e.g. pulling plugs out by the cord at an angle) scenarios.Push-in connections are the devil as well...although the personal experience I've had with that involved the hot, not the neutral, so the symptoms were clear-cut.

author: alm
author_rank: Super Contributor
timestamp: July 12, 2017, 08:15:14 pm
content: How would the symptoms be any different for single phase appliances for an intermittent neutral vs intermittent hot?

author: Nusa
author_rank: Super Contributor
timestamp: July 12, 2017, 08:23:48 pm
content: Quote from: alm on July 12, 2017, 08:15:14 pmIf the hot is missing, you get no power at all to the appliance when it's interrupted. And if it's intermittant, there won't be an over-voltage scenario.

author: alm
author_rank: Super Contributor
timestamp: July 12, 2017, 08:33:37 pm
content: How would you get power to an appliance with an interrupted neutral at the power outlet? Without a neutral no current will flow, and hence no power. Obviously this is different for three-phase appliances.

author: Nusa
author_rank: Super Contributor
timestamp: July 12, 2017, 09:05:31 pm
content: Quote from: alm on July 12, 2017, 08:33:37 pmThat would be true for a two-prong outlet (very obsolete) or a two-prong plug in a three-prong outlet. I believe we're talking about three-prong cords plugged into three-prong outlets. The safety ground may fill the role of the neutral, depending on how the appliance is wired. That's a bad thing, but it's better than letting the entire appliance become a live wire waiting for a human to complete the circuit to ground.

author: Ampera
author_rank: Super Contributor
timestamp: July 12, 2017, 09:56:28 pm
content: Quote from: Nusa on July 12, 2017, 09:05:31 pmI've heard human tastes like pork...Heard it, that's all.

author: alm
author_rank: Super Contributor
timestamp: July 12, 2017, 10:41:13 pm
content: Quote from: Nusa on July 12, 2017, 09:05:31 pmAn appliance that shorts neutral to ground is broken and should trip the GFCI (if present). At that point you have two faults: a faulty outlet and a short in an appliance. That is quite different from the situation in 2750's house, which is a working appliance but a broken outlet. With a working single-phase appliance, the symptoms of broken or intermittent neutral or live would be exactly the same.

author: rstofer
author_rank: Super Contributor
timestamp: July 12, 2017, 10:50:36 pm
content: Quote from: tooki on July 12, 2017, 07:24:11 pmYou don't get much for $0.49https://www.lowes.com/pd/Eaton-10-Pack-15-Amp-125-Volt-White-Indoor-Duplex-Wall-Outlet/1099255I tend to prefer the high price spread at around $10 each, especially when I was specifying them for my employer. I simply didn't want to get into a discussion about quality. Hubbel 5362 all the way!https://www.amazon.com/Hubbell-HBL5362W-Duplex-Receptacle-Industrial/dp/B000LE6N56Prices vary and I suspect I can get receptacles for less than $0.49 with a little shopping around.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 13, 2017, 05:39:15 am
content: How can that possibly be of any quality if it's less than $1?The cheapest I can get is €3.80 for one european socket, with wholesale discount.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 13, 2017, 06:09:00 am
content: We put 'em every few feet.Regarding the push-in thing, duplex sockets allow you to branch off them. That is to say, there's two hot & neutral terminals bonded together. With the push-in connections an intermittent or otherwise poor neutral connection is possible, and it'll affect the downstream branch (up-tree?). With the screw lugs, that's practically impossible.alm: No difference. Unless it's on 3 wire with a shared neutral, then do the math.

author: Ampera
author_rank: Super Contributor
timestamp: July 13, 2017, 06:29:55 am
content: Quote from: Jeroen3 on July 13, 2017, 05:39:15 amThe US is a nation of cheap crap. Our houses, cars, utilities, roads, services.

author: Vgkid
author_rank: Super Contributor
timestamp: July 13, 2017, 06:44:01 am
content: I will happily keep the knob and tube wiring in our house. It probably predates a bunch of members houses.

author: BradC
author_rank: Super Contributor
timestamp: July 13, 2017, 07:05:51 am
content: Quote from: TwoOfFive on July 12, 2017, 09:56:28 pmThe other, other white meat.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 13, 2017, 12:18:06 pm
content: I had to google knob-and-tube wiring...

author: Unknown
author_rank: Unknown
timestamp: July 13, 2017, 05:11:23 pm
content: Quote from: TwoOfFive on July 13, 2017, 06:29:55 amI don't know why you continually feel the need to insult the country you are living in with every few posts, but some of us actually enjoy living here, have worked in the industries you belittle, and disagree with you in words that simply aren't appropriate to be posted here. Maybe you can take a cue from this and tone it down.

author: SeanB
author_rank: Super Contributor
timestamp: July 13, 2017, 05:56:05 pm
content: Quote from: Jeroen3 on July 13, 2017, 12:18:06 pmStill better than DCC gutta percha wire, which crumbles if you so much as look at it, or open a cover that has not been disturbed since this wire was new around 70 years ago. Then it turns to powder, and you are left with having to replace all the cable in the conduit back to the fuse box, as any disturbance will cause a hard short to the grounded steel conduit it is in. Knob and tube still works even without the covering, just is kind of touchy to go near, but you can replace the sleeving easy enough with a few wraps of self amalgamating tape and have it back to work.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 14, 2017, 05:56:07 am
content: Knob and tube wiring was actually pretty safe despite the opinions of some self styled experts. For most of it, the two conductors are suspended 2" off any wood and they were separated about 10". Not much to go wrong there. Its Achilles' heels were that it required some craftmanship to make the soldered joints and ceiling light fixtures. At ceiling fixtures the two conductors were quite close. Someone would inevitability screw in a hundred watt bulb to these for 50 or 60 years and cook the insulation on the wires until it cracked.

author: Cubdriver
author_rank: Unknown
timestamp: July 14, 2017, 06:28:33 pm
content: Ideally receptacles should be daisy chained with taps rather than by connecting both the supply and the feed to subsequent receptacles to the terminals. Taps (wire nutting the supply and downstream feed lines together with a short stub wire that then connects to the receptacle) are extra work, and result in more crowding in the box, but a wire nutted connection, if properly done, is very reliable. With taps, a bad connection at a receptacle affects that outlet only whereas with all wires connected to each receptacle a bad connection will mess up everything downstream as well.-Pat

author: Jeroen3
author_rank: Super Contributor
timestamp: July 14, 2017, 08:38:27 pm
content: Wire nuts, or "lasdoppen" in dutch, are used here.Like these.They are reliable if you get them from a reputable brand, and they are very easy to use. The 222 series also handles stranded wire.

author: Monkeh
author_rank: Super Contributor
timestamp: July 14, 2017, 09:06:03 pm
content: Quote from: Jeroen3 on July 14, 2017, 08:38:27 pmThose.. are not wire nuts. Thankfully, because wire nuts suck.

author: Cubdriver
author_rank: Unknown
timestamp: July 14, 2017, 09:21:33 pm
content: Quote from: Monkeh on July 14, 2017, 09:06:03 pmWhy do you say that wire nuts 'suck'? I've used literally hundreds of them without any issue.-Pat

author: Monkeh
author_rank: Super Contributor
timestamp: July 14, 2017, 10:38:25 pm
content: An argument which has been had many a time before.They involve permanent damage to the conductor, are not reliably reusable, prevent proper inspection, are not suitable for fine stranded conductors..Someone is sure to come up with a counter argument to all of these points, not least 'I've used lots'. Well, we don't use any and we're happy!Next up: 120V vs 240V, 50Hz vs 60Hz, AC vs DC..

author: Cubdriver
author_rank: Unknown
timestamp: July 14, 2017, 11:05:57 pm
content: Quote from: Monkeh on July 14, 2017, 10:38:25 pmOk. To the best of my knowledge they're not intended to be reusable, if the splice is properly made it doesn't need inspection, and they're not meant for fine stranded conductors. House wiring here in the US (where the OP is located) is normally done with #12 and #14 AWG solid conductors, this is their intended application, and for it they work just fine. And BTW, a crimp terminal will cause permanent 'damage' to a conductor when installed; does this mean that they 'suck', too? Horses for courses - there's a reason that there are skazillions of different types of connectors made - they have different uses. I'm inclined to say that those (such as wire nuts) that are listed in the electrical code (and have been fordecades) are suitable for use in electrical wiring.You don't use them and are happy. That's fine. We don't use ring circuits for mains supply wiring, and we're happy too. Though they don't make sense to me, I don't say they suck.-Pat

author: Monkeh
author_rank: Super Contributor
timestamp: July 14, 2017, 11:19:23 pm
content: Quote from: Cubdriver on July 14, 2017, 11:05:57 pmAnd yet they're used that way.QuoteHow can you determine it's been made properly?QuoteAnd yet they're commonly used with such, even in UL listed equipment.QuoteCrimp terminals are a different beast.. also not used in these applications, not least because they're permanent, not to mention unsuited to solid conductors.QuoteThey make historical sense to me.. but they also somewhat suck and should be avoided in new installations as a matter of course.E: Also, I somewhat enjoy getting yanks riled up over their electrics. Don't take it personally. You drive on the wrong side of the road, too.E2: And, to further elaborate: IMO they suck as they're a connector with only two selling points: They're cheap, and people are used to them.