EEVblog #1164 - Xbox Baptism Of Fire - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: December 28, 2018, 03:20:10 am
content: A retro look at the 2005 Xbox 14 million unit power cord replacement issue and a teardown and analysis of the supplied protection device from Microsoft.

author: Tek_TDS220
author_rank: Regular Contributor
timestamp: December 28, 2018, 03:55:34 am
content: I'm not sure, but is the 'inverted' design used to keep the power low (and the relay off) during operation?Incidentally iFixit did a teardown of the new Xbox One X (https://ifixit.org/blog/9450/xbox-one-x-teardown/). It's beautiful.

author: ataradov
author_rank: Super Contributor
timestamp: December 28, 2018, 03:55:43 am
content: I doubt they actually designed this thing on the spot. This is probably some existing product relabeled and trip current adjusted.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: December 28, 2018, 04:00:22 am
content: Maybe the board monitors current leakage to ground for shock hazard in comparison to the current load of the XBOXElectronic GFCIhttps://home.howstuffworks.com/question117.htm

author: sakujo7
author_rank: Contributor
timestamp: December 28, 2018, 04:32:33 am
content: The solenoid coil placement could be to cover an unlikely case where the earth leakage circuit itself or the rectifier fails and becomes a short. They clearly wanted something that would reduce the risk of fire no matter what.A youtube commenter suggested the micro could be looking for a particular wave shape that indicates arcing, which would allow it to act like a fast-blow fuse yet not trip on inrush current. If it's not something like that, then it's definitely overkill...

author: EEVblog
author_rank: Unknown
timestamp: December 28, 2018, 05:13:00 am
content: Quote from: sakujo7 on December 28, 2018, 04:32:33 amThat might make sense. The PIC 12F675 would have just enough grunt to do that crudely I guess.

author: EEVblog
author_rank: Unknown
timestamp: December 28, 2018, 06:05:02 am
content: Apparently this is an "Arc Fault Circuit Interrupter" (AFCI) that continually monitors the current for the presence of arcs caused by such an intermittently faulty power connection. Hence the complexity and micro that would be using the ADC to continually monitor the current. It's not just a simple 610mA electronic fuse, although it almost certainly has that function too, hence the label.﻿These seem standard in US outlets since 2014?https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter

author: Whales
author_rank: Super Contributor
timestamp: December 28, 2018, 06:38:21 am
content: Dave: what makes you think Microsoft designed this? Wouldn't it make more sense that this is an off-the-shelf product with a custom trip level and a rebadge? Esp given the custom relay construction.https://duckduckgo.com/?q=inline+RCD&iar=images&iax=images&ia=imageshttps://duckduckgo.com/?q=inline+AFCI&iar=images&iax=images&ia=images

author: EEVblog
author_rank: Unknown
timestamp: December 28, 2018, 06:41:37 am
content: Quote from: Whales on December 28, 2018, 06:38:21 amThey have the clout to do this, and the Not Invented Here syndrome perhaps.QuoteWith hindsight, yes.

author: helius
author_rank: Super Contributor
timestamp: December 28, 2018, 06:45:54 am
content: @15:00:There were power strips (APC was one brand) that were recalled for causing fires due to shorted, overheating MOVs*. The remedy was to redesign them with thermal fuses held against the MOVs.MOVs are sacrificial components, but unfortunately their most common failure mode is to go permanently low resistance, and further heating in a death spiral. It's good to see that Microsoft designed them in correctly, even in 2005, several years before the APC recall happened.*https://www.cpsc.gov/Recalls/2013/schneider-electric-recalls-apc-surge-protectorshttps://recall.apc.com/en

author: Whales
author_rank: Super Contributor
timestamp: December 28, 2018, 06:59:57 am
content: Quote from: EEVblog on December 28, 2018, 06:41:37 amI've love to lookup the codes next to thetick of approvalc-tick, see if that brings more info about who the OEM might be.I think the place I'm supposed to search isERAC. Alas I'm having no luck -- I can't decipher what their terminology means and there are lots of server errors. One error simply dead "Dead!"The searches look like they need at least 5 fields to be filledexactly correctly-- quite a way of telling people to go away.Anyone know how to search those codes next to the c-tick up?EDIT: Turns out that's not the Australian tick of approval, it's ac-tick. As a consumer: I had no idea, that's really bad symbolic language.

author: draconx
author_rank: Newbie
timestamp: December 28, 2018, 08:02:55 am
content: The separate test board has the RU mark on the silkscreen which means it was independently tested by Underwriters Laboratory, right?So that perhaps justifies a two board design... so the test board can be certified separately from the rest of the product. Could be a requirement to sell this in some jurisdictions?

author: JoeMuc2013
author_rank: Contributor
timestamp: December 28, 2018, 09:28:35 am
content: Hey all,all tech details aside, I still don't understand what is the approach here. So some Xbox models (0.01%, right) released the magic smoke? Why? And how is an inline fuse going to prevent that?Do they try to save the precious Xbox by just switching it completely off once the current draw goes beyond expected levels? In that case, that's not a particularly good solution, or is it? Imagine the rage in MMO or RPG gamers if their console cuts out in the middle of a fight? The hardware might have survived the power issue then, but will it survive the destructive energy of mad users?Maybe I'm completely wrong with this but afaik a fuse is just to cut power for safety. If the design fault is in the built-in power supply of the Xbox, wouldn't that have to be replaced instead of this makeshift solution? And what caused the power supplies to fail in the first place?Thanks for any info on this!I have never owned a console but this could just as well happen with any other consumer device, so it's a generally interesting matter.Happy new year in advance to everyone

author: riccardo.pittini
author_rank: Regular Contributor
timestamp: December 28, 2018, 11:03:34 am
content: Dave: One comment MOV and Thermal fuseYou can buy directly MOV with integrated thermal fuses. If you make a decent power supply everything should be after the fuse, including MOVs (in some cases it's not possible, e.g. when you design a power supply to withstand large surge pulses).MOVs with time they degrade, heating up, so it is a good design rule to place a MOV after the main fuse. If the MOV is directly in parallel to the AC line then use a thermal fuse.

author: Whales
author_rank: Super Contributor
timestamp: December 28, 2018, 11:09:42 am
content: Quote from: JoeMuc2013 on December 28, 2018, 09:28:35 amRead the other posts in this topic and the comments on youtube: it's not a standard fuse-style circuit breaker, it's an AFCI.QuoteYou're right it's not the best solution. It can only try to prevent smoke/fire after a fault happens, but thismightbe enough in the eyes of Microsoft. Even if it fails to do so 10% of the time it could still theoretically reduce the number of failures to '3' instead of '30'. Additionally: if people keep turning it back on (because it keeps tripping) and then have a house fire, Microsoft can then say it's their fault for ignoring the clear warnings from a safety protection device.The motivations and viewpoint of a company are different to the motivations and viewpoints of an ideal society.

author: AndyC_772
author_rank: Super Contributor
timestamp: December 28, 2018, 12:20:35 pm
content: Quote from: JoeMuc2013 on December 28, 2018, 09:28:35 amI'm imagining it right now, it's both hilarious, and hilariously unimportant by any standard.If an AFCI makes the difference between "my Xbox cut out and lost me some game progress" vs "my Xbox cut out and set fire to my home", then it's done everything that was required.Remember, a games console is a corner case in terms of safety and reliability, ie.- it's made in huge numbers, and is sold to people who will take every possible level of care of it, from extreme mechanical sympathy to utterly reckless abuse - so it needs to be extraordinarily safe, but...- if it simply fails to function, the real-world consequences are almost definitively trivial. "Someone can't play a video game" is about the single most unimportant consequence a failure could possibly have, so any need for reliability is all about the manufacturer's reputation. That's a commercial decision, and I can easily see how replacing a power brick made more sense than replacing entire consoles.

author: JoeMuc2013
author_rank: Contributor
timestamp: December 28, 2018, 12:32:32 pm
content: Quote from: AndyC_772 on December 28, 2018, 12:20:35 pmI agree, technically it prevents the worst. BUT: if this is a known design flaw in the Xbox, serious corporations would recall the units in question, and fix them, no matter the cost. This action is certainly more expensive than providing an ACFI to all users, no matter whether they are affected or not, but tackling a problem at its root would establish a good hardware manufacturer's reputation whereas this is a ridiculous cheat of a solution that I would never accept if I were an Xbox owner.If you bought an electric vehicle that is under the known risk of fire in mid-travel, and the manufacturer sends you an AFCI for you to "fix" it yourself, which would cause the vehicle to do an emergency stop and power down once something odd was detected, this behavior would cause a class action lawsuit against the vehicle's manufacturer. I know, it's an odd comparison but anyway... what I want to say is that Microsoft gets out of this too easily. It's their fault, not the customer's.So yeah, I'm happily not an Xbox owner, but after this story I'll consider twice before I ever buy any mains-powered hardware from Microsoft.

author: AndyC_772
author_rank: Super Contributor
timestamp: December 28, 2018, 01:35:16 pm
content: I offer by way of counter-example the fact that this particular serious company, on this occasion, chose to do otherwise.I also suggest that it would be a mistake to avoid buying mains powered equipment from a company which has clearly already had an expensive lesson in reliability, and which should undoubtedly have a check for this type of design flaw as part of its QA procedure now. Holding a grudge beyond the point at which a company has released new designs that are free of this flaw doesn't help anybody.For an automotive product, the consequences of failure can be incomparably different. If a fault in my car causes it to shut down on the highway, then that's a big deal - but if it just means the CD player doesn't work any more, that's inconsequential unless the fault also starts a fire.

author: Ferroto
author_rank: Frequent Contributor
timestamp: December 28, 2018, 07:58:17 pm
content: AFCI's are a huge pain in the ass and will trip if you have any inductive loads such as motors or ballasts on the same branch circuit. They are also highly susceptible to RF interference as seen here.

author: Rasz
author_rank: Super Contributor
timestamp: December 28, 2018, 08:45:38 pm
content: Dell and HP had similar problems, lucky for them laptop power supplies are easier to recall avoiding half ass bodges like one demonstrated here.https://www.pcworld.com/article/2599100/hp-recalls-6-million-laptop-power-cords-that-can-pose-fire-and-burn-hazards.htmlhttps://www.cnet.com/news/millions-of-dell-power-adapters-recalled/Apple is clueless when it comes to power delivery, and got almost EVERY SINGLE laptop charger wrong, starting with powerPC laptops, and ending at USB-C cablesmost catching fire too.https://discussions.apple.com/thread/551178https://www.macworld.com/article/1140453/Apple_sued_over_alleged_MagSafe_fire_hazard.htmlhttps://discussions.apple.com/thread/6037659https://www.apple.com/support/ac-wallplug-adapter/https://www.apple.com/ie/support/usbc-chargecable/

author: orion242
author_rank: Unknown
timestamp: December 28, 2018, 08:55:19 pm
content: Quote from: Ferroto on December 28, 2018, 07:58:17 pmGuy I work with just finished building a new house. First power outage he fired up his generator, only to find out none of the AFCI's would hold under gen power. Brilliant!

author: Barny
author_rank: Frequent Contributor
timestamp: December 28, 2018, 09:54:08 pm
content: Microsoft continued the tradition of bad power suplys.I've the first generation of Surface Pro.The power suply is completly without bend protection.(Primary and secondary)I replaced the ca. 300mm (ca. 12 inch) long power cord after it started to arc & smell with an new one after one week of usage.I planed to replace the cable from the beginning, because the original was next to unusable short.Ca. 3 years later I got a new power cord because of an recall.The low voltage side got an bend-protection made of multible layers of heat shrink and hot glue.Here is the recall-site from microsoft:https://support.microsoft.com/en-us/help/4040585/surface-ac-power-cord-recall-surface-pro-surface-pro2-surface-pro3

author: Kleinstein
author_rank: Super Contributor
timestamp: December 28, 2018, 10:25:17 pm
content: The design of the connector mainly hold by the solder joints could be the problem and reason for the recall. So it would be a fault waiting to happen in units that see a lot of stress on the connector and maybe have a not so good solder quality.The protection device might very well be a separate product already designed before. Still the construction looks a little odd - not made to be sold in the millions. I can under stand that this could be cheaper than a full recall of the XBOX itself. They likely would have to replaced the PS board and organize twice the shipping. When in a hurry they may not have the time to design a cheaper protection box and get it tested.An really interesting tear-down.

author: ataradov
author_rank: Super Contributor
timestamp: December 28, 2018, 10:27:46 pm
content: But I still don't see how the crack on the connector will be remedied by the external device. And I don't see how anything more serious than a crack can happen here.

author: helius
author_rank: Super Contributor
timestamp: December 28, 2018, 10:42:01 pm
content: The failure mode is that the high contact resistance makes the connector pins red hot. There is a chance the PCB material begins to smolder. The hope is that arcing inside the joint can be detected using that device and shut off power before it gets hot enough to ignite.

author: AndyC_772
author_rank: Super Contributor
timestamp: December 28, 2018, 11:13:59 pm
content: If the PCB itself is UL 94V-0, what actually starts burning? The connector itself? Isn't that a non-flammable plastic?

author: Rasz
author_rank: Super Contributor
timestamp: December 29, 2018, 05:11:01 am
content: Quote from: ataradov on December 28, 2018, 10:27:46 pmno no, external device is to prevent lawsuit, not fix the fault. Thats what recalls in US are for.

author: Rerouter
author_rank: Super Contributor
timestamp: December 29, 2018, 06:11:02 am
content: Its common enough in the automotive stuff, Solder joint begins to fail due to vibration / flexing stress, the joint gets hotter, the joint degrades further, the board begins to carbonize around the joints, and this starts spiraling towards a hard short near the input connector.Combine this with all the dust, and sweat/oil that builds up over the years and you have a nice bit of kindling.

author: Whales
author_rank: Super Contributor
timestamp: December 29, 2018, 06:14:27 am
content: Quote from: AndyC_772 on December 28, 2018, 11:13:59 pmIt's touching the case.Also: if you can get the charring to go far enough it might become conductive. Then all hell breaks loose.

author: helius
author_rank: Super Contributor
timestamp: December 29, 2018, 07:27:27 am
content: 94V-0 means self-extinguishing, not non-flammable. If a source of heat is present, the material can smolder.Dust may also be present and an ignition hazard.

author: james_s
author_rank: Super Contributor
timestamp: December 29, 2018, 07:44:15 am
content: Quote from: orion242 on December 28, 2018, 08:55:19 pmAFCIs are terrible, a friend of a friend builds houses, he told me the #1 issue they deal with post-sale is people complaining about the AFCIs and wanting standard breakers installed. The NEC requires AFCIs almost everywhere now, they're expensive, run hot, and are notorious for nuisance trips. IMHO they're a band-aid for something that really ought to be outlawed, the spring loaded push-in terminals on the back of cheap receptacles. I have personally dealt with three of those that burned up, one of which was in my own house. The terminals develop a bad connection, heat up and get worse. At least with mine I was fortunate that the wire melted off and opened the circuit before it caused any further damage.

author: Clear as mud
author_rank: Regular Contributor
timestamp: December 29, 2018, 06:34:44 pm
content: Quote from: EEVblog on December 28, 2018, 06:05:02 amWith each code revision, the National Electrical Code has been requiring them in more and more places, in residential buildings. But they're not quite standard in practice, yet. It depends on the jurisdiction. Many have not yet adopted the 2014 or 2017 codes, so they're still enforcing only the 2011 or 2008 version.Many electricians don't like them because of nuisance trips, but my own view is that they've been around for over a decade, so the manufacturers have had time to work out the problems with them. I installed some AFCI breakers in my own house, and the only time I had one trip was when there actually was an arc on the circuit.However, they remain 10 times the cost of a standard breaker, and I think they're not worth that cost, in terms of value of property protected. The amount of extra loss incurred due to not having AFCI breakers is less than the cost of the AFCI breakers to protect everything.

author: james_s
author_rank: Super Contributor
timestamp: December 29, 2018, 11:06:09 pm
content: It only applies to new construction or remodel jobs too, you don't have to upgrade existing systems. Some AFCIs may be better than others but those that I've dealt with caused a lot of nuisance trips, especially with anything containing a universal motor. The breakers themselves got alarmingly warm too, which tells me there's a significant amount of parasitic consumption. It may not be a lot per breaker but when you figure a typical panel might have 20 or more breakers that adds up.I'm wishing that I had replaced my panel with a more modern unit back before the requirements got so draconian. At this point it would cost me so much to make a modest improvement in safety and usability that it's not worth it and I'll just stick with my original 1979 panel. It would be better if it were allowed to upgrade an old system without bringing it all the way up to present day compliance, it would still be an improvement over what is there.

author: akimmet
author_rank: Contributor
timestamp: December 30, 2018, 06:08:03 am
content: AFCI breakers are still the bane of residential electricians in the USA. All known makes still have issues with nuisance tripping and high current electric motors. The second there is enough load to bog down the motor, the AFCI will trip. Toasters are another common cause of nuisance trips.I can understand the safety aspect, but I agree with James_s. Banning the use of back-stabs and wall-nuts would do much more for preventing electrical fires than AFCI breakers ever would. This is somewhat like when GFCI outlets were first required in potentially wet locations. It took over two decades before GFCI outlets became good enough to not be annoying.Probably the second most annoying thing is tamper-resistant outlets. Even the good ones can be difficult to operate with some plugs. I have seen people jam a screwdriver in the slots to break the break the tamper-resistant interlock, so things plug in easier.

author: sibeen
author_rank: Frequent Contributor
timestamp: December 30, 2018, 06:19:58 am
content: Quote from: akimmet on December 30, 2018, 06:08:03 amCould someone please post a photo of these items so that I can understand what you lot are on about.

author: LapTop006
author_rank: Unknown
timestamp: December 30, 2018, 09:06:30 am
content: PerWikipedia:QuoteThat last bit has a link referencingthis ARRL post.

author: james_s
author_rank: Super Contributor
timestamp: December 30, 2018, 05:57:41 pm
content: Quote from: sibeen on December 30, 2018, 06:19:58 amThere's not much to see with the back stab terminals. There are just some holes in the back of receptacles and switches, you strip the wire and poke it in the hole and a spring loaded contact engages holding the wire in and making the electrical connection. The problem is that the contact area is tiny and the contact is nothing more than a bent strip of sheetmetal. Over time it oxidizes and heats up, losing its springiness which of course makes the connection worse and it gets hotter and the cycle repeats until it burns up. They are awful and should be banned, I refuse to use them but contractors love them because they save so much electrician time.Those TR receptacles mentioned by someone here are another thing I loathe. They cost more than commercial grade but they're built like the cheap residential grade. It's often hard to get plugs into them and hard to get test probes into them too. They're required everywhere now and it's stupid, I'm never going to have kids and if I did I'd put childproof covers on the accessible receptacles. When I've had to get something inspected I install the cheapest TR receptacles I can find, then swap them out with nice commercial grade stuff after the inspector has signed off.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: December 30, 2018, 08:34:22 pm
content: Quote from: sibeen on December 30, 2018, 06:19:58 amI have a minute to take a picture for clarity. First is backstab, second is using the terminal lug. The former is not considered acceptable around here but rather by convention then code I think. Note the little catch that makes forming the wire quick and easy, and the checkering on the terminal plate to prevent having the wire dragged around when tightening the screw. It takes 5 seconds to make rather than 2 for the backstab. Keen eyed will spot this Canadian variant.

author: akimmet
author_rank: Contributor
timestamp: December 30, 2018, 10:01:02 pm
content: Here is a website showing what are commonly called "wall nuts" in North America.Like "back stab" outlets, they hold the wire in with pressure from a spring clip.https://www.wago.com/us/wire-splicing-connectors/push-wire-connector-for-junction-boxes/p/773-104

author: james_s
author_rank: Super Contributor
timestamp: December 30, 2018, 10:53:21 pm
content: Those Wago connectors come on a lot of light fixtures these days. I throw them away and use wire nuts instead, far more secure connection and not much harder to install. The push-in stuff works fine for a while, but it doesn't age well.

author: sibeen
author_rank: Frequent Contributor
timestamp: December 30, 2018, 11:07:30 pm
content: Quote from: akimmet on December 30, 2018, 10:01:02 pmI design switchboards up to a few thousand amps as part of my day job and those Wago 'push wire' type terminals are ubiquitous, and there's nothing wrong with that as they are being used for sensing and not as moderately high current carrying style connectors.Using those 'back stab' type outlets just seems rather crazy and really head scratching considering the hoops that the National Electricity Code in the USA and Canada make the rest of the industry go through. I live in one of the IEC lands and we look at the household switchboards that are made in the US and they really look like something out of the 80s compared to an equivalent IEC rated switchboard. At least three times the size and as clunky looking as all getout. I'm amazed that the NEC is so stringent at the start of the electrical distribution within a house/factory etc, and will then let a really cheap piece of crap be installed as the final distribution point.

author: Brumby
author_rank: Unknown
timestamp: December 31, 2018, 12:00:19 am
content: I've seen those backstab connections causing issues in desk lamps. I can't imagine the potential for problems with anything pulling even moderate current. *shudder*

author: james_s
author_rank: Super Contributor
timestamp: December 31, 2018, 12:42:15 am
content: Quote from: sibeen on December 30, 2018, 11:07:30 pmI had the opportunity to help a friend replace his panel when I was visiting the UK, it was interesting to see up close how different it all is. I found the European style panels to be cramped and rather flimsy looking although they seem to do the job given houses there have a tiny number of circuits in comparison. You can get compact panels in the US too but they're lousy, get 20-30 circuits typical of an average sized house in there and the panel is packed full the day it is installed, with no room for future expansion. My own panel is one size up from the compact ones and it's too small, I'd really like to install a fullsized panel, they're about 3' tall and luxuriously spacious, lots of room to route wires and space for expansion. The good industrial style ones have solid copper bus bars.I do find it ridiculous that such cheap terminals are allowed, I never use anything less than spec grade (commercial/industrial) hardware and I often use hospital grade receptacles where they are heavily used. The higher cost of the hardware is peanuts compared to the total cost of the job and high quality receptacles don't get all sloppy and loose after a few years.

author: sibeen
author_rank: Frequent Contributor
timestamp: December 31, 2018, 01:37:29 am
content: Of course some allowance needs to be made for the difference in voltages used in the two systems and therefore the different levels of current. A nice, clean, healthy 240 or 230 volts versus that cheap and nasty 120 or 110 volt stuff. And don't get me started on the frequency!

author: james_s
author_rank: Super Contributor
timestamp: December 31, 2018, 05:33:12 am
content: What's wrong with the frequency? 60Hz means smaller, lighter motors and transformers, less flicker in iron ballast discharge lamps (less of an issue than it used to be) and no real downside. Also we have 240V here too, nearly all large appliances like ovens, cookstoves, electric clothes dryers and stuff like large air compressors are 240V. For whatever reason, US domestic service tends to be higher capacity than elsewhere in the world. A typical service to a modest single family home is 200A 240V. There tends to be less on a given circuit, for example my friend's house in the UK has nearly the entire second floor on one single ringmain, pop that and the whole upstairs goes dark. My house has multiple separate circuits for lighting on each floor, and multiple circuits for receptacles. If you manage to trip the breaker you usually still have lights.Whatever the case, that (EE) friend and I have had some pretty extensive discussions on the matter and we have both come to the conclusion that neither system is a clear winner, both have advantages and disadvantages, mostly they're just different.

author: Whales
author_rank: Super Contributor
timestamp: December 31, 2018, 06:50:14 am
content: Quote from: james_s on December 31, 2018, 05:33:12 amPersonally: 60Hz transformer hum sounds less comforting (impatient?). It never bugged me until I noticed it in other people's recordings.Yes that's a valid reason to make a whole country change grid freq. When I'm supreme leader: this and more. Dropout fuses on every home switchboard, 2.4GHz electric blankets, majority of freq spectrum opened up for public use, ban on audio frequencies that I can't hear (the people might be talking about me behind my back!), etc

author: sibeen
author_rank: Frequent Contributor
timestamp: December 31, 2018, 07:14:38 am
content: James_S, I was joking, hence the smiley.

author: McRib
author_rank: Newbie
timestamp: December 31, 2018, 01:17:39 pm
content: I used to mod and repair these and I believe they changed the design of the power supply to use stranded wire from the receptacle to the ps board. There was quite a few solder repairs i did on that style Xbox but none after the change.

author: james_s
author_rank: Super Contributor
timestamp: December 31, 2018, 07:12:40 pm
content: Quote from: Whales on December 31, 2018, 06:50:14 amI noticed the 50Hz hum for about the first 24 hours, motors, transformers, everything sounded a bit weird, then I got used to it and when I got back home the 60Hz stuff sounded a bit weird for a few hours. Where it was really noticeable was old style discharge lights where the 50Hz flicker was much more pronounced. Now that so many things use switchmode power supplies the frequency is less and less relevant.I recently learned that Japan has two separate power grids, one 50Hz and one 60Hz, that has to be inconvenient, especially in the past. Seems odd to me that they never standardized, wouldn't most 50Hz infrastructure work at 60Hz? Just spin the generators faster?

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: December 31, 2018, 07:27:56 pm
content: I'm guessing that incredibly complex board is an arcing detector. The use them in houses in some parts of the USA. Likely the dry joint on the socket connections was the problem.

author: james_s
author_rank: Super Contributor
timestamp: December 31, 2018, 08:42:34 pm
content: Arc-Fault circuit breakers are required on nearly all residential circuits nationally across the USA for all new residential construction and any added or altered circuits in existing homes. IIRC the way the code is written they are mandated for all "outlets" but the definition of "outlet" covers not only receptacles but also light fixtures so effectively they are required on all 120V branch circuits.

author: rrinker
author_rank: Super Contributor
timestamp: January 02, 2019, 05:32:08 pm
content: I refuse to use those backstab connections when replacing outlets. Hate those with a passion, and thee's actually a good reason to. I haven't come across those Wago connectors yet in any residential wiring, the last light fixtures I replaced in my house all used wire nuts. I have encountered a variation on the backstab connection - it wasn't a self-gripping thing, it was simply an alternative way to insert the wire to be held in place by the screw on the side, which clamped down on the wire with as much metal in contact as you get when wrapping the wire around the screw. Sad that it has to come to this, but it seems too many people haven't a clue as to which way to wrap the wire around the screw.When replacing failed outlets in my house (usually the cheap ass stuff used in the original construction fails to hold the plugs as the contacts lose tension, or in a couple of case, the whole plastic cracked off - seriously I wonder what some people do with their corded appliances), I NEVER use the cheap bulk packages, I always get the higher grade ones, they cost more but are far more robust. And if it's work I'm having someone else do, I specify those type, not the cheap contractor grade garbage. Or I'll buy the things rather than have the contractor get them, so I know they are using the good stuff. This is a far bigger problem than the type of plug or the voltages used or whatever - the hardware comes in all levels of quality from "you're really trying to burn your house down, aren't you?" to "Hit this with a sledge hammer and it still maintains integrity and protection from shocks". It's all a matter of how much you are willing to pay, like most anything else.

author: james_s
author_rank: Super Contributor
timestamp: January 02, 2019, 07:50:47 pm
content: I replaced every receptacle in my house after I bought the place. Quite a few of them were so loose the plugs would fall out with the slightest tug, and a wall wart type plug would just fall out under its own weight. A couple of them were actually falling apart, the whole plastic face fell off when I removed the cover plate. Spec grade receptacles are only about $2.50 each, sure they cost more than the 99c residential grade stuff but even for a large house you're talking maybe a couple hundred bucks max. I have a hard time understanding why someone would build a $500k house and then cheap out on a couple hundred bucks that would considerably reduce the chance of their house burning down or requiring expensive repairs later. Calling an electrician once to replace a faulty receptacle is going to eat all the savings and then some.

author: Monkeh
author_rank: Super Contributor
timestamp: January 05, 2019, 07:13:15 pm
content: The issues you all seem to have with spring terminals are all down to yours being cheap, nasty ones, not the type of terminal.

author: james_s
author_rank: Super Contributor
timestamp: January 05, 2019, 10:25:04 pm
content: That's irrelevant, the spring terminals are all cheap and nasty, that doesn't mean it's not possible to make good spring terminals but absolutely none of the backstab terminals are well made. The screw terminals on the other hand are generally good, it's harder to screw that up. Given the simplicity of a screw, I don't see much reason to reinvent the wheel.

author: Monkeh
author_rank: Super Contributor
timestamp: January 05, 2019, 10:43:28 pm
content: Quote from: james_s on January 05, 2019, 10:25:04 pmIt's not irrelevant when you're bad-mouthing the decent ones (Wago) in the same sentences.

author: floobydust
author_rank: Super Contributor
timestamp: January 05, 2019, 10:47:27 pm
content: The Wago spring-clamps are excellent, I've used bigger ones on terminal blocks up to 50A, albeit with stranded wire- not solid wire.They are not popular in North America aside from use in locomotives because they stay tight with high vibration and temperature swings in railroad apps.Duplex outlets are crap with the back-stab and solid wire. Many melt downs keeping electricians making money. It's just a single leaf making contact and the spring fatigues with age.

author: richnormand
author_rank: Unknown
timestamp: January 05, 2019, 10:56:30 pm
content: Every time I had a hot electrical socket it was one of these back-stab crap. Replaced with a proper loop and screw type and no issues.Are the back-stab still legal? Can't imagine when used with Al wiring....I have Wago connectors that I use in the electronics shop but always wondered if they are legal to use in house wiring instead of the twist-on Marr connectors (that do seem to work fine BTW)?

author: james_s
author_rank: Super Contributor
timestamp: January 06, 2019, 12:30:37 am
content: Quote from: Monkeh on January 05, 2019, 10:43:28 pmI'm bad mouthing them because I've personally dealt with them (or clones, I don't really know). I've had wires pull out several times, recently had to do some troubleshooting at a friend's house because several lights had stopped working after the electricians finished. I found those silly push in splices all over, a couple of wires had fallen out and were the source of his problem. I replaced every one I encountered with a proper wire nut and no more problems. Maybe they're fine for low current control stuff by why they're legal for line voltage I don't know. They're only marginally easier to install and they're much less secure than a proper joint. The contact area is miniscule, and I know from numerous experiences with the back-stab type on receptacles that over time oxidation tends to creep in causing localized heating which causes the springy metal to soften and lose its grip resulting in more heat. I've encountered at least 3 melted down receptacles due to that problem and I'm not even an electrician by trade, I can only imagine how many instances occur in the wild. A proper connection should have a significant surface area and a tight mechanical joint. Screw terminals and wire nuts both meet that criteria, I've never seen either one fail except in a couple of outdoor things where the junction box filled with water.

author: Monkeh
author_rank: Super Contributor
timestamp: January 06, 2019, 12:41:59 am
content: Quote from: james_s on January 06, 2019, 12:30:37 amHmm, me too.QuoteHave you tested the pull-out force on them? It's.. impressive. Conductors do not just 'fall out' of the real deal.QuoteBoth the contact area and the current bar are greater than the conductor CSA, try again.QuoteThey are gas tight...

author: james_s
author_rank: Super Contributor
timestamp: January 06, 2019, 12:50:09 am
content: Quote from: Monkeh on January 06, 2019, 12:41:59 amNo, they're not, not the kind that come with residential electrical fittings here. The back-stab terminals on US electrical fittings are universally trash. The Wago type connectors that come with US domestic light fixtures are (to the extent I have experienced) universally trash. Gas-tight push in terminals with good contact area may exist but you won't find them packaged with domestic electrical fittings so in the context of situations where AFCI breakers are used (USA residential), these connectors don't exist. The push-in type that are ubiquitous are junk.They may not be manufactured by Wago, that term is a bit of a colloquialism like Kleenex or Hoover.

author: Monkeh
author_rank: Super Contributor
timestamp: January 06, 2019, 12:54:34 am
content: Quote from: james_s on January 06, 2019, 12:50:09 amSo you haven't personally used the proper type but you're still bad mouthing them using your experiences with trash.