House Fire - Looking for Advice - Page 1
Forum section: electronics / beginners

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 02:38:54 am
content: All people and pets are fine, which is great. But, about 9:30PM Xmas Eve, my Mom had a smoke detector go off. Long and short is that an outlet in one of her upstairs bedrooms (she is a very serious quilter, and it was her fabric storage room) shorted and caught the storage case in front of it on fire which led to a fairly significant fire. The fire department showed up within about 12 minutes and put it out, but there was substantial damage.So, of course we're working with insurance, a restoration contractor, etc. They're saying it's a 3-5 month process because of the smoke and water damage in addition to the relatively-contained fire damage.Here's why I'm on EEVBlog asking for info, though... The FD shut off the power at the main breaker panel in the garage, but no breakers were tripped. Additionally, about 2 months ago, she lost an entire circuit (some lights and all outlets) in another room - again without a breaker tripping. An electrician came out and found the wires for that circuit melted behind the panel. I didn't get to chat with him, but according to my Mom, he said it looked like the previous owner swapped a 20A breaker into a 15A circuit. So he put a new 15A breaker there, but that circuit wasn't involved in this incident.A touch more info on the XMas fire: she had a space heater running in that room before the fire. It's a new space heater and runs on a timer. When the smoke detector first went off, she immediately thought it was the heater and went up to unplug it. But, it was off and neither the heater nor the wire/plug were warm. She went back downstairs, alarm went off again, and when she went back up and opened the door to that room, there was a small fire on the opposite wall from the heater/plug. So I suspect the heater had been on pulling some current, that's when the short or whatever started, and after the heater shut off it took it a while to evolve from some sparks into an actual fire.My fear is that insurance/contractors are mostly interested in just getting this patched back up, but I'm concerned about what is so wrong with this house (built in 2007, so not old) that wires are melting and fires are starting. Could it just be bad/undersized wire throughout? Even then, why aren't breakers tripping? I'm hoping to get an electrician I trust, but that may or may not happen (availability and insurance compatibility being the driving factors). Feels like something is really off, and I don't know what to ask or how to make sure I'm not getting bullshit answers.So, any thoughts on what might be going on here and/or what I should be pushing for? I am not an emotional man, but I'm very keenly aware of how much worse this could've been if my Mom had already been asleep, or not home, or any number of other things. I'm not amiable to accepting half-answers from hurried contractors on this - I want to understand the problem and have full confidence it's behind us.

author: p.larner
author_rank: Frequent Contributor
timestamp: December 27, 2023, 04:14:43 am
content: i would imagine the claming screws for the wires bit into the copper and got loose as it settled,leading to arcing under load+heat hence fire,ive always noticed the screws holding the wires in the sockets need another half turn after a few months.

author: Dan123456
author_rank: Regular Contributor
timestamp: December 27, 2023, 04:40:48 am
content: Fuck mateThat really, really sucksI am really, really glad that everyone is OK thoughI’ll leave the speculation on the cause the the more experienced / professional guys as I am definitely not an expert and don’t want to give you a bum steer for something so seriousThat said, do you know if any of the other circuits in your home have the same issue of not popping breakers when they should?I’m just thinking, if yes, the professionals might be able to look for the fault in those and make a determination based on what they find there

author: bdunham7
author_rank: Super Contributor
timestamp: December 27, 2023, 04:46:37 am
content: What brand/model are the breakers and service panel? Does it not have arc-fault (AFCI) breakers?

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 05:03:52 am
content: Quote from: Dan123456 on December 27, 2023, 04:40:48 amNo other circuits I'm aware of that have had issues, but this (fire) was the first issue with this circuit too so little comfort there.

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 05:04:41 am
content: Quote from: bdunham7 on December 27, 2023, 04:46:37 amI believe the new breaker(s) recently replaced for the first issue are AFCI and would be the only ones, but I will take some pics tomorrow to get full info.

author: TomWinTejas
author_rank: Regular Contributor
timestamp: December 27, 2023, 05:49:30 am
content: Quote from: meshtron on December 27, 2023, 05:04:41 amIf the locality followed the NEC and was built in 2007, the bedrooms should all have AFCI breakers. She would have missed the 2008 update by just a year, and that specified family rooms, living rooms, hallways, libraries, sunrooms, gamerooms, etc. Most recent code added laundry rooms and kitchens. But not all states adopted the AFCI requirements... so it really can vary.However, that doesn't mean that you can't retrofit most of the breakers to have AFCI protection. They aren't cheap, but perhaps if you can find an authorized dealer (I wouldn't trust random eBay stores) who has a contractor pack, maybe you can find a deal for buying an entire panel's worth.

author: Ian.M
author_rank: Super Contributor
timestamp: December 27, 2023, 05:52:23 am
content: https://lappelectric.com/what-is-backstabbing-a-receptacle-or-switch-and-why-is-it-important-to-hire-an-electrician-that-does-not-use-this-method-of-wiring/

author: Jwillis
author_rank: Super Contributor
timestamp: December 27, 2023, 09:41:53 am
content: Quote from: Ian.M on December 27, 2023, 05:52:23 amI agree 100%. If you look inside at the contacts, Theirs, at best, 30% of the contact area compared to the side screws. Never use the stab contacts regardless of code compliance. Why this still code compliant baffles me.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2023, 10:40:57 am
content: Quote from: Jwillis on December 27, 2023, 09:41:53 amBecause it is a lot faster to install, and thus will be used. Likely the wall outlets all need to be opened, and all the ones with the backstabs redone to use the screws, and if it is a loop through definitely so, and if there is any hint of arcing when you remove the wires replace the socket entirely. Also the AFCI breakers in the panel are a cheap upgrade, as the cause likely was that heater, with the socket that caught fire being looped through to feed the heater socket. Replace all the breakers with AFCI ones, expensive, but with the known shoddy work from the builder, likely given a day to install all electrical, from incoming feeder, meter socket, panel and the entire wiring, before the drywall workers get to close the walls up, and them chasing to finish all the time, all wiring connections in all sockets, switches and lights are suspect. Alos check that nobody swapped out the cabling for CCA wire, as that also is very common, as the cheap cable with no copper is very attractive to the cowboy builder, seeing as it is a quarter the price, and otherwise looks identical, just is junk.

author: CaptDon
author_rank: Super Contributor
timestamp: December 27, 2023, 02:38:51 pm
content: A close look at the socket where the fire started will probably reveal that it was part of a 'wired through' receptacle where current or the 'home' circuit to the breaker panel was on one set of screws and another wire was then connected to the other set of screws and lead across the room to where the heater was. In the U.S. they are installing 15 amp breakers with crappy assed #14 wire. N.U.E.C. allows it but it is shit work indeed. Your Mom's heater probably drew 12 to 13 amps on wire only rated to 15 max in walls. If they 'back stabbed' the connections they may have been in violation of code? Back stabbing is usually only allowed on lighting circuits and in some districts and townships NO receptacle or switch may be wired by back stabbing as it often leads to fires! It sounds like the electricians who wired the house may have taken dangerous shortcuts and a previous owner may have done even worse things.

author: Stray Electron
author_rank: Super Contributor
timestamp: December 27, 2023, 02:48:48 pm
content: Quote from: Ian.M on December 27, 2023, 05:52:23 amThis! this! This!I've seen a LOT of outlets that start getting warm and all of them have had back-stabbed connections. In fact, I have a back stabbed light switch that is also staring to fail. IMO back-stabbing switches and outlets should be illegal.IMO you should have a GOOD electrician take a close look at all of your breakers and make sure that the wiring size is matched to the breaker amperage. Per the NEC the breaker size can not exceed the rated capacity of the wiring but a lot of homeowners do install larger breakers. I think that your insurance company would pay for this if done in conjunction to your insurance claim. If possible I would also try to have all of your outlets and switches and lighting outlets checked for signs of overheating and for back-stabbed connectors.BTW does you mom's home have aluminum wiring?If it does then that's a whole other issue!

author: themadhippy
author_rank: Super Contributor
timestamp: December 27, 2023, 04:02:05 pm
content: QuoteAre you certain it was an electrical fire and not something opposite the heater getting heated full blast and smouldering,opening and closing the door on the first visit caused enough of an airflow to start it burning.

author: tooki
author_rank: Super Contributor
timestamp: December 27, 2023, 04:06:00 pm
content: Meshtron: I’m glad your mom is OK and only material goods were lost.As for back-stabbing: I have a genuine question about these. How do they differ in their internal construction from the push-in (and other cage-clamp) terminations widely used in Europe? I ask because there seems to be consensus in USA that back-stabbed connections loosen over time, worse than screw terminals, while the cage-clamp connections used in Europe (both push-in, manual release, and lever-locked) all seem to bemorereliable than screw terminals. So clearly there is a difference in how they’re made and how they work, despite being superficially the same.

author: tooki
author_rank: Super Contributor
timestamp: December 27, 2023, 04:10:26 pm
content: Quote from: Stray Electron on December 27, 2023, 02:48:48 pmThe house was built in 2007, I thought plain aluminum wire had been banned for new installations for decades. Copper-clad aluminum (CCA) is still allowed though. :/

author: CaptDon
author_rank: Super Contributor
timestamp: December 27, 2023, 05:13:49 pm
content: CCA wire is just as trash as all aluminum wire. Some of the old house trailers with aluminum wire that hasn't been upgraded or already burnt to the ground can't even be insured or bought with a mortgage. The wire really is that dangerous. Also, be aware that there are fake SquareD circuit breakers out there and I was given a pile of breakers from a salvage yard that was reclaiming railroad wayside gear that was installed in 2010 and promptly decommissioned only 5 years later. Among the breakers several were fakes!! They are hard to tell from the real ones in some cases but in other examples the fakes are obvious.

author: xrunner
author_rank: Super Contributor
timestamp: December 27, 2023, 05:32:56 pm
content: Quote from: SeanB on December 27, 2023, 10:40:57 amSecond on the inspection. You've had a fire, so open ALL outlet covers after power is turned off of course. Inspect ALL outlets and see if shoddy work was done, and replace or re tighten screws as needed.

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 05:48:23 pm
content: Quote from: themadhippy on December 27, 2023, 04:02:05 pm100% certain. Heater was more than 12 feet from where the fire started and it's a small, new, safe heater that wasn't even warm to the touch. Did a walkthrough with the fire marshal around 1:30AM on XMas day and he agreed 100% it was the outlet, nothing to do with the heater other than it was probably (yet to confirm, but very likely) pulling current through the outlet that failed.

author: drvtech
author_rank: Regular Contributor
timestamp: December 27, 2023, 06:05:07 pm
content: Quote from: tooki on December 27, 2023, 04:06:00 pmThe thing about cage clamps etc compared to screw clamps is that the former have a spring which maintains a relatively constant pressure on the wire , regardless of thermal expansion, mechanical vibration, movement etc. With a screw terminal you set an initial pressure with the screw but then, as thermal effects and cold-flow of the materials change the dimensions of the various elements (the wire, the screw, the cylinder that you insert the wire into), that alters the pressure on the wire. It's the same problem that we solve by using spring washers in nut and bolt fastenings.

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 06:09:48 pm
content: Thanks everyone for the feedback and thoughts.I was unaware that back-stabbing is a problem - good to know that.I will try to get to the failed outlet today, but we're a bit at the mercy of the "Origin Specialist" insurance is bringing in - can't move/touch anything important before that happens (and of course we don't even have a date yet). But, I'll see what I can. If the failed outlet is back-stabbed, that seems very likely to be the culprit.Also, when my Mom first bought the house about 1-1/2 years ago, she had them install a dedicated 30A circuit for her CNC long-arm quilting machine (as I mentioned, she's a very serious quilter). That circuit does indeed have AFCI breakers on it. The recently replaced circuit where someone had a 20A breaker on a 15A circuit, the electrician just replaced with a 15A non-AFCI breaker. I have a bunch of meetings at the house later today, will get some good panel pictures.But, I think the right move is that we do at least the following:- Have the electricians inspect and replace or rewire all outlets in the house (and explicitly state we want screw-termination)- Add AFCI breakers for all bedrooms, etc.- Confirm the existing panel is properly rated, installed, and wired to support all the electrical needs of the house- Insurance offers a device called "TING" at no cost that monitors power for the house in real-time, we'll have them install that tooBeyond that, the rest is just managing the argument between the restoration contractor who sees a juicy project and insurance who thinks maybe a coat of paint and a carpet clean will be enough (I'm exaggerating, but this is the insurance game).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 27, 2023, 06:15:34 pm
content: Regarding mechanism -- no shorting need occur, or even much arcing (I don't know offhand if an AFCI is likely or guaranteed to trip in cases like this, or too late to matter; but something is better than nothing, I mean). The biggest hazard is if there's a substantial load on the circuit (near rating, but even a fraction of ampacity can be enough), and a loose connection -- a voltage drop, maybe it's a loose screw, fatigued wire, oxidized or bent or overheated or otherwise damaged clamp contacts, whatever -- that generates heat localized somewhere, and which leads to a runaway condition (hotter wire, looser contacts, more oxidation, more resistance, more arcing).Any connection can do it; in-wall splices, outlets, plugs and cables themselves. Of course, splices (hopefully..?!) are only done at junction boxes, or outlets where chained, and plugs/cables you can see on the equipment itself.The telltale sign is low and/or intermittent voltage at the outlet, under load; but due to the intermittency, this isn't a good testing method. I mean, if you see the voltage droop, something's fucky, but if you don't, it could still be faulty and you just haven't seen it flinch yet.It might also be handy if devices shut off automatically under low-line conditions, but even 90VAC is considered acceptable input to much equipment, partly to deal with long extension cords and nuisance brownout conditions; short of doing statistics, load range sensing, or arc detection in the equipment (which might not work well, or be feasible at all?), there's just not much that can be done from that side unfortunately.So doing it right the first time, and inspecting it to such standard, is the best solution here. Maybe just the outlets are top suspect right now, maybe a spot check of accessible junction boxes is a good idea too. Hopefully, insurance, inspectors or electricians are supportive of your concerns here -- it's a big deal to happen at all, and it's unfortunate that your strongest mitigation (insurance) is purely financial: after the damage has already been done (and, assuming they consider it compliant going in).Tim

author: meshtron
author_rank: Regular Contributor
timestamp: December 27, 2023, 06:31:36 pm
content: Quote from: Stray Electron on December 27, 2023, 02:48:48 pmI'm almost certain all the wire is copper - no aluminum and no CCA. But, that's based on the switches and outlets I've replaced which is definitely not all of them - so still need to confirm.Trick with insurance and the "restoration" vendors (who are essentially a GC that is self-performing most trades) is that they kind of come in a bundle. It is allowed for us (well - me) to manage all the subs myself, but with a full-time corporate job plus two side businesses plus her house being ~45 minutes away from me, it's nearly impossible for me to manage that well. That said, I have 2 other electricians coming out to give competing proposals for electrical scope. I've been up front with everyone about current state and planned path, but having more opinions and observations is almost always better than fewer.In my opinion, a perfect outcome is where both the restoration vendor and the insurance adjuster both hate me, but don't want to argue with me anymore.

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 27, 2023, 08:59:49 pm
content: Definitely do swap all outlets for good quality parts. I like "spec. grade" (this will be stamped on the steel back strap) this is the "commercial" grade option at most box stores. Those are nice to wire too, not to be confused with backstab junk, the back wire option on a spec grade outlet clamps the wire between two metal plates with a screw, very secure.

author: CaptDon
author_rank: Super Contributor
timestamp: December 27, 2023, 10:43:52 pm
content: Always remember, you can buy 15 amp duplex receptacles for $.99 at Lowes and Home Depot, BUT you can also buy 15 amp or 20 amp rated receptacles for around $3.50 and up and there is a reason for that, quality!! All of my rewire jobs here in the states have been 12 gauge NM wire with ground, good quality 20 amp rated receptacles (which run cool with a 1500 watt space heater plugged in) and a 20 amp breaker at the panel. If I have multiple outlets on one breaker then I use a junction box. From the junction box to the breaker panel is a 'home run' and all outlets have at most one set of wire nuts (in the junction box) between the outlet and breaker panel. NO WIRED THROUGH RUNS!! I like to use the receptacles with the screw tightened compression clamps (good 15A and 20A receptacles have this feature). The type of enclosure containing the receptacle and also what is against that enclosure can either promote or retard the spread of fire!! A fire in a wall is a serious matter!!! Often the fire breaks out in the ceiling or floor above the original source of the fire. This new construction using 14 gauge wire and 15 amp receptacles / breakers is a joke!!! A 1500 watt space heater will cause noticeable heating of 14 gauge wire and is almost at the max rated capacity of the receptacle and breaker. Besides the voltage drop is unacceptable!!! 120 volts at the breaker and only 108 at the space heater!!

author: meshtron
author_rank: Regular Contributor
timestamp: December 28, 2023, 02:22:23 am
content: Long day. But, met the electrician at the house and they confirmed what you all told me and agreed with the plans laid out above. There are some open questions about whether insurance is responsible for upgrading the home to current code or not, but I hope to help that tip in our favor. Electricians inspected the panel today (an Eaton panel) and said everything looks in order but they recommend changing out all but the 3 new breakers, most of them with AFCI.Anyway thanks again for the tips and education, feeling better tonight and optimistic for a good outcome.

author: Jwillis
author_rank: Super Contributor
timestamp: December 28, 2023, 06:00:51 am
content: Quote from: tooki on December 27, 2023, 04:06:00 pmI haven't installed European outlets for obvious reasons. But judging from installation videos, the European receptacles use a compression screw where the North American stab connection is a friction fit with spring tab.The picture shows the internals of a switch, but the connection for receptacles are the same.

author: uer166
author_rank: Super Contributor
timestamp: December 28, 2023, 06:10:12 am
content: Wago-type cage clamp connections are known to be generally more reliable and less likely to cause fire due to pressure consistency. I wonder why "back-stabbing" outlets is worse, maybe due to quality issues of the actual cage clamp?

author: nctnico
author_rank: Super Contributor
timestamp: December 28, 2023, 06:40:22 am
content: Probably a combination of low quality gear and loss of clamping force. The wagos are prone to failure too under high load. A good quality wire-nut which has a spring with square edges that eat into the wire from Conex for example, is more reliable when installed properly according to a very experiened electrician I know. I'm in the process of replacing all wagos with Conex wire nuts after the wago that fed the washing machine started to melt.

author: SeanB
author_rank: Super Contributor
timestamp: December 28, 2023, 07:52:17 am
content: You want the best connection you use uninsulated crimp on connections, with a heatshrink sleeve, so as to get a gas tight bond to the wire, and really good contact. Wago works because they normally, on the genuine ones, have a decent size copper busbar in them to provide the low resistance, and a spring or clamp that keeps constant pressure as the wire slowly flows. Will say the modern sockets, irrespective of brand, are all a lot flimsier than the old stuff, I tend to keep the old ones in good condition, and use them for high power loads, as they normally are screwed together, so you can dismantle them and retension the contacts, which are thicker brass, and often with a spring that keeps the contact good.By me screwnuts are almost all invariably ceramic, so they will still work, even if they are glowing bright yellow.

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 28, 2023, 04:56:28 pm
content: Quote from: nctnico on December 28, 2023, 06:40:22 amIn the US the Ideal brand tan color/size "twister" wire nut seems to be the preferred quality option, never heard of Conex. I've not used a ton of them, but they have held up for me in places including a 10 gauge 30A split phase garage panel feed that sees enough abuse (not by me) that the panel in the garage pops the 30A main at least a few times a year.

author: meshtron
author_rank: Regular Contributor
timestamp: December 28, 2023, 07:00:10 pm
content: Forgot to add - I couldn't get in to take a good pic of the (remnants of) offending outlet as there is all kinds of stuff piled in front of it. Insurance adjuster made it clear we should avoid touching anything in there until their "Origins and Causes Specialist" does their work. Of course, they don't even have an estimate yet for when that person is going to come out. So, in the meantime, all that stuff is sitting there sopping wet and will start to mildew soon. :|I'm hoping to be back there tomorrow and make take a GoPro on a stick to see if I can get close. I will feel very satisfied if I find it to be a back-stabbed outlet, and I will feel substantially less satisfied if I find screw-terminal connections though I understand those can still be done wrong/poorly and even if not wrong can get loose over time.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 28, 2023, 10:13:58 pm
content: Quote from: CaptDon on December 27, 2023, 05:13:49 pmAluminium wiring doesn't have to be trash or dangerous. Overhead power lines use it no problem. The relevant difference is probably quality of installation and maintenance. In domestic settings aluminium wiring does indeed seem to be trouble to the point of insurers bowing out. It's not worth whatever savings it may provide.CCA has become quite widely available in networking too, and there too it's causing issues. Avoid if remotely possible.

author: amyk
author_rank: Super Contributor
timestamp: December 28, 2023, 11:53:42 pm
content: Aluminum wiring needs special connectors; problems occur when it's connected with fittings designed for copper.

author: Jwillis
author_rank: Super Contributor
timestamp: December 29, 2023, 12:02:30 am
content: Quote from: BrokenYugo on December 28, 2023, 04:56:28 pmThe Marrette is preferred in most new builds provided that it's used correctly. The twisting of the insulated wire should be at least 2 inches before the marrette is twisted on. These connections last for years without fear of disconnection and arcing. As for screws coming loose on receptacles and light switches over time sounds like total BS. I've on worked many electrical repairs on older homes and haven't found one single screw connection that came loose on it's own. Sounds more like an excuse to do a quick cheap ass job over a good job.

author: uer166
author_rank: Super Contributor
timestamp: December 29, 2023, 02:12:14 am
content: Quote from: Jwillis on December 29, 2023, 12:02:30 amDo you have actual statistics or is this purely anecdotal on a small sample size? I've seen a much higher rate of melting/thermal events on screw-connected appliances vs Wago-connected ones. It's over 10s to 100s of ks sample size, and the failure rate for both is way too small to be significant over a small sample size of what a single person can do.If I had a choice I would still use properly rated, genuine Wago cage clamp connections that are UL listed. Not only are they consistent, but they also depend less on the skill of the schmuck installing them. The backstabbing is definitely not the same, and I don't know enough about it to comment.

author: nctnico
author_rank: Super Contributor
timestamp: December 29, 2023, 03:15:01 am
content: Quote from: BrokenYugo on December 28, 2023, 04:56:28 pmThose 'Ideal' twister wire nuts look comparable to the Conex ones. For the Conex ones, good practise is to unscrew these after fitting to check. The coiled spring inside should stay on the wires. If not, then it wasn't screwed on properly. The Conex ones have a hexagon shaped top so you can use a spanner or socket wrench to mount them more quickly but I've also seen specific hand tools to improve grip / mounting ergonomy.

author: TomWinTejas
author_rank: Regular Contributor
timestamp: December 29, 2023, 06:32:21 am
content: Quote from: CaptDon on December 27, 2023, 02:38:51 pmCode usually specifies that devices are used in accordance with the manufacturer's specifications... and manufacturers that produce outlets that provide backstabs specify that it is permissible. So it's usually not a violation of code unless a municipality decides to be more stringent.My father is a retired electrician and would never backstab an outlet and recommended that I rewire all my outlets that were backstabbed. He didn't do new construction where backstabbing is commonplace. The crews are more interested in speeding up the process than doing quality work and the general contractors are more interested in saving money wherever possible.

author: rsjsouza
author_rank: Super Contributor
timestamp: December 29, 2023, 05:03:22 pm
content: Quote from: SeanB on December 28, 2023, 07:52:17 amI usually use the crimp on larger wire sizes (6, 8, 10 AWG) - if they are stranded. In case not, I use a tight twist grip (to be sure the copper contact is solid and follow code), then solder and use thick heatshrink with that sticky goo to avoid any influence of the elements.Quote from: SeanB on December 28, 2023, 07:52:17 amInteresting info on the ceramic wire nuts. I wasn't aware of the maximum temperature rating on those. McMaster-Carr carries the regular stuff, the higher temp (up to 150°C/300°F) and the ultra-high temp ceramic (650°C or 1200°F). Quite remarkable!https://www.mcmaster.com/products/wire-nuts/I have never used a Wago, but the cheap knockoffs that I have seen go straight to the trash can. A twist wire nut works much better.

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 29, 2023, 06:43:55 pm
content: Quote from: nctnico on December 29, 2023, 03:15:01 amInteresting, any nut I've removed keeps the spring, which come to think of it is somewhat spooky as some people inevitably will reuse them. Sockets are sold to drive the winged nuts with a drill or screw gun, and the Ideal Twisters do have a 5/16" hex on the end formed by the ribs, though as with anything potentially life critical I prefer to hand assemble everything. What I like to do to ensure they're all fully/evenly inserted (except for mixing stranded and solid, where the stranded is recommended to lead a little) and properly twisted together by the nut is tape the wires into a bundle a few cm back, then put the nut on, twist until tight and twists start appearing outside the nut, seems to work.Pre twisting and trimming to strip length is also permitted but I never do it that way, the way I figure it the wires will be better mated with how the nut grabs the wire bundle from all around and forces them together as its screwed on.

author: nctnico
author_rank: Super Contributor
timestamp: December 30, 2023, 02:55:36 am
content: In school I've learned to pre-twist the wires before putting the wire nut on.

author: tooki
author_rank: Super Contributor
timestamp: December 30, 2023, 03:03:59 am
content: Quote from: drvtech on December 27, 2023, 06:05:07 pmI’m fully aware of all of that. But if you take a moment to review my question, you’ll notice that I didn’t ask about clamp vs screw, though. I asked “why are European clamp connectors reliable, while American backstab connections are not? What’s the difference in construction that is responsible for this discrepancy?”

author: tooki
author_rank: Super Contributor
timestamp: December 30, 2023, 03:19:08 am
content: Quote from: Jwillis on December 28, 2023, 06:00:51 amMost receptacles here use screw terminals. But I wasn’t talking about only the things on receptacles. What are widely used here are both WAGO terminals (in lieu of marrettes), but also the various types of cage clamps used extensively for DIN rail terminal blocks:- “manual” (use tool to open the clamp so wire can be inserted or removed)- push-in (tool needed to open clamp to remove a wire, but solid wires and stranded wires with ferrules can be pushed in without the tool. Stranded wire without a ferrule requires the clamp to be opened manually first.)- pre-tensioned push-in (clamp is held open out of the factory by an internal hair-trigger, like a mousetrap, so that even a thin stranded wire can be inserted without a tool. The trigger releases the clamp onto the wire. A tool is used to open the clamp, which also rearms the trigger mechanism. I think Phoenix Contact is unique in offering this type.)- lever-lock (lift plastic lever to open the clamp)In all of these, the closed clamp is spring-loaded and thus maintains tension on the wire even if the wire shifts, making them safe to use with both solid and stranded wire (or even, god forbid, stranded wire tinned with solder, though this is illegal for mains work).Major manufacturers include WAGO, Phoenix Contact, and Weidmüller.What I am wondering is why these European spring clamps are highly reliable, exceeding the reliability of screw terminals, while the backstab terminals on North American outlets and switches are unreliable. I’m curious about how their construction differs, such as to produce such diametrically opposite reliability outcomes.

author: tooki
author_rank: Super Contributor
timestamp: December 30, 2023, 03:31:29 am
content: Quote from: nctnico on December 28, 2023, 06:40:22 amWhich model WAGO was it?The thing you describe is exactly how WAGO terminals work, I don’t think Conex is any different at all.

author: coppercone2
author_rank: Super Contributor
timestamp: December 30, 2023, 04:20:36 am
content: the wire nut digs into the wire as you twist it to make a ultra high pressure connection. the wago is a sandwich. It sounds like the conex has something like wire wrap going on.

author: nctnico
author_rank: Super Contributor
timestamp: December 30, 2023, 05:45:09 am
content: Quote from: tooki on December 30, 2023, 03:31:29 amNo. The spring is a coil made of square wire which eats into the wires as you twist the wire nut on. Like wirewrap as Coppercone2 already noted.The Wago model that has given me problems:

author: coppercone2
author_rank: Super Contributor
timestamp: December 30, 2023, 08:07:35 am
content: was it with ferrules?I am often suspicious of ferrules because I have seen even supposedly the best manufacturers just crimp it with some total bullshit like pliers. Tried to trick me too but I know what it looks like if you crimp it and tighten it down properly, not like what I found in that test equipment.. If its done like that I was wondering if it could be more harm then good. I recommend installing your own modules BTW. They crimped the ferrule on the over priced cable inside of the instrument with needle nose pliers it looked like. Normally what I expect in your ultra expensive cable made with so-so wire and cheap interconnects is the NRE on the swiss made atom force microscope and xray inspected crimp die made to the standards of the US mint. They did not even use that possibly dodgy ferrule crimper on the back of some pliers.

author: CaptDon
author_rank: Super Contributor
timestamp: December 30, 2023, 03:48:19 pm
content: New receptacles and switches that can be back stabbed can no longer accept wire larger than #14AWG although years ago the holes were big enough to accept #12AWG. Back stabbing and 'wiring through' on a 20 amp branch circuit is sure to cause problems. What is the biggest problem with the back stab devices?? They usually sell for under $1.50 U.S.D. and their quality is total shit with what appears to be very little quality control even if they are wearing a good brand name. Made in china crap!!! We really don't see 'WAGO' stuff in U.S. homes. As for screwing on the wirenut then screwing it off to see if the spring part stays on the wire......Total bullocks!!! I see good electricians always pre-twist the solid copper conductors and then apply the wirenut. Ceramic wirenuts show up in ovens and furnaces to connect the high temperature fiberglass covered wires together near the flame front. Some of the worst connections in industrial machines that I have had to service were the green Phoenix connectors with the little screw that gets tightened with an Excelite 'Green Tweaker'. The wires nearly fall out after a year of vibration!!! Also, some of the orange wirenuts don't have any metallic insert!! Be careful what brand you buy. Often the ones supplied in lighting kits are crap!!

author: tooki
author_rank: Super Contributor
timestamp: December 30, 2023, 06:31:00 pm
content: Quote from: nctnico on December 30, 2023, 05:45:09 amOh, sorry, I misread, I thought you meant a Conex non-twist device. What you describe is how all twist-on wire nuts work, isn’t it?That’s the WAGO 273. (Discontinued but replaced by the 2273 series.)

author: tooki
author_rank: Super Contributor
timestamp: December 30, 2023, 06:36:30 pm
content: Quote from: coppercone2 on December 30, 2023, 08:07:35 amWAGO, for example, specifies in its catalogs that ferrules, when used on spring clamp terminals, must be crimped “gas-tight”, which means a proper crimp, not a half-assed crimp from pliers.So while I trust my $20 Chinese hex-shape ferrule crimper for ordinary use with screw terminals (where the screw terminal itself will compress the heck out of the ferrule, making it irrelevant whether the ferrule is crimped tight in advance) or for low-current applications with spring clamp terminals, I wouldn’t trust it for high-current use in spring clamp terminals. For that I’d want square or trapezoid ferrule crimps done with a top-quality ferrule crimper — or no ferrule at all, since most types of spring clamp terminals (just not the cheapest push-in types) are compatible with bare stranded wire.With that said, ferrules are mandated by some electrical codes (like in Europe), since they ensure no wayward strands can short against other terminals, and they definitely make inserting stranded wire way easier!

author: jmelson
author_rank: Super Contributor
timestamp: December 30, 2023, 07:38:10 pm
content: My dad remarried after my mom died. He moved into the house she had, which was built in the 1960's. He mentioned that he had lights blinking on and off in some rooms. He called an "electrician" in, and he said that was normal. His next-door neighbor, an EE said that guy's an idiot. I agreed, and opened up the breaker panel and tightened all the screws on the breakers. That seemed to solve the blinking lights problem.What I think happened is that the circuit in that room was "daisy-chained" from one outlet to another. A loose connection at one of the intermediate sockets overheated and started a fire in the wall. Check that there is no aluminum wire in the house, and that no sockets or switches use the compression ("back stab") feature. Only use the screws. Wow, my condolences on the damage, but it could have been WAY worse!Jon

author: Gyro
author_rank: Super Contributor
timestamp: December 31, 2023, 10:28:30 am
content: I have a bit of a problem with Wago boxes (ie, Wago connectors slotted into their rectangular boxes with cable strain relief slots) being designated 'maintenance free' by the simple action of putting a cable tie through the lid retaining tab. This implies no inspection and they end up sealed in floor spaces, never to be seen again.https://www.wago.com/gb/installation-terminal-blocks-and-connectors/wago-box/p/207-3301Edit: Possibly more house fire related, I just noticed that Wago produce and specify an 'Alu-Plus' contact paste for using Aluminium cables in their connectors. This apparently prevents oxidation and Aluminium-Copper electrolytic corrosion. I don't know if anything similar is used in any US Aluminium (or CCA?) wire installations with 'backstab' sockets?

author: Stray Electron
author_rank: Super Contributor
timestamp: December 31, 2023, 02:19:04 pm
content: Quote from: Gyro on December 31, 2023, 10:28:30 amNoalox paste is made by Ideal corporation and is widely used in the US to seal aluminium wiring connections. Or it's supposed to be. In fact, I think that it's use is required when using aluminum wiring. But many cheap and in a rush contractors leave it out. All it does is delay oxidation of aluminum wiring and it might help prevent oxidation (aka burning) of overheating connections but it's not a cure of loose connections that develop I2R heating. Copper wiring really doesn't oxidize so I doubt the Noalox would make an difference when used with copper wiring and it might lead to electrolytic corrosion due to the dissimilar metals so I wouldn't recommend it. The problem with back-stab connects is that they only have a very small contact area with the wire and are very subject to I2R heating. And they're so small that that they don't dissipate much heat so they overheat very easily.

author: themadhippy
author_rank: Super Contributor
timestamp: December 31, 2023, 02:21:17 pm
content: QuoteNo different to the 1000's of landmine junction boxes stuffed under floors,and they dont have a cable clamp.