Testing 7 Wago-like Wire Connectors For Science And Fire

At the intersection of saving a few bucks and expensive home insurance claims due to a house fire, we find clones of certified and tested electrical connectors, even when many would argue that so-called wire nuts are fire hazards no matter how many certification labels are on them. When it comes to no-fuss wire connectors, Wago clamp connectors are an attractive target to save some money on due to their perceived high cost. But how expensive are they really?

This was the thought behind a recent video by [GreatScott!] (also embedded after the break) when he hopped onto everyone’s favorite e-commerce website and searched for ‘clamp lever terminal’. The resulting selection of seven connectors come in a wide variety of shapes, colors and configurations, though all are supposedly rated for mains (250 VAC) voltage and safe enough to put into a permanent installation.

While running the connectors through their paces with high-current, fire and mechanical strength tests, the conclusion was that all are good enough for hobbyists use and some brief connections while testing, but that only the ones with independent certification marks (like VDE) filled him with enough confidence to consider using in house wiring. One of these being the connectors by the German brand ViD, which would seem to be a slightly cheaper alternative to the Wago connectors, with similar guarantees of safety.

At the end of the day it is the certification that matters, after all, since long-term reliability is of primary concern with house wiring, not whether a few Euros were saved on material costs.

31 thoughts on “Testing 7 Wago-like Wire Connectors For Science And Fire

  1. Wish I had known about these a month ago. I had to make a bunch of junction box wire-nut connections through 5in dia. ceiling holes for can lights. While the mixed stranded/solid wires were a nuisance with wire nuts, it looks like WAGO thrives on them.

    1. It really does, I’ll never wire stranded to solid core wire any other way going forward. I changed some lights in my theatre room and the wagons were perfect for the job.

  2. I had a chat with a Wago rep about these devices. I was advised that the number of connections on genuine WAGO connectors is deliberately limited because of this phenomena.

  3. I’ve also bought several models by mail from that country far away, and my feelings are mixed.
    Some of them are quite all right, while others are just garbage to work with. I had Blue wago 221 knockoffs (not tested by Scott) and the holes in these are too small, which basically means you can put the bare copper through the hole, but not the isolation.

    Overall, the price difference is just too small to bother with, but there are some exceptions.
    I quite like the model tested by Big Clive in: https://www.youtube.com/watch?v=OP86SxqP7I8

    Also a nice tip:
    I do not do much mains wiring, but I mostly use these on my electronics workbench for temporary connections for all kinds of higher current connections such as power supplies, motor controllers with MOSfets etc. They are almost as easy to use for high current connections as banana plugs, and you don’t accidentally disconnect them.
    For stranded wires, I’ve made a few with lengths varying between 5cm and 30cm, stripped them, and tinned the ends. This is not recommended for permanent connection, but for temporary connections on your workbench this works pretty good.
    You could also work with ferrules, but the “standard” size is too short, but it’s quite easy to order longer ferrules, they are available.

    A disadvantage is that they do wear out. I’ve tested some, and after about 500 openings and closings the springs get a very noticeable metal fatigue and clamping force drops and even the spring breaks. But that is not such a big deal. You feel the difference, and 500 connections for a 20ct part is quite good. You can half the cycles during use by not closing the levers when there is no wire in them. Don’t push down the levers when you store them!

    1. I don’t think it is reasonable to expect that these are cycled 500 times. The use case for a wire nut type of connection is to make the connection and leave it in place at least until a fixture needs to be replaced. Maybe a few cycles would be expected. Does the manufacturer claim a number of allowable cycles? Does the UL certification test explore this?

      1. I was not complaining about the 500 cycles.
        I’m perfectly aware that these things are designed to be installed just once (or maybe a few times during wiring modificatons).

        I’m quite happy and find 500 cycles very acceptable for this complete abuse of these connectors. Overall it is just 0.01 cent or so per cycle, and you can easily feel when the force starts diminishing and it’s time to replace them.

        This is only for electronics works on your desk and when you’re watching what you’re doing. It’s not to put behind a panel in a wall and to sit there for an indefinite time.

    1. If they are properly installed and used, there is nothing wrong with using wire nuts. Improperly installed or overloaded and they are indeed a fire hazard, just like any other improperly installed or overloaded electrical device.
      Source: My 20+ year career as a commercial and industrial electrician.

      I don’t have any experience with Wago connectors, so I can’t comment on whether or not they are superior.

      1. I’ve only encountered one incident involving a wire nut. I smelled a burning smell and traced it back to the water heater. I opened the wiring box/control panel and discovered a wire nut partially melted and burnt. If I had to guess the root cause, it was likely due to the connection not probably being made leading to a high resistance connection. If I had arc-fault circuit breakers installed it could have possibly caught it.

    2. In the UK is is the norm to find “chocolate blocks” in mains wiring: rows of large bore screw-terminal connectors (terminal blocks) supplied in a long stick that can be chopped down to size (or pre-cut 3-terminal packs for most home use for the lazy). Positive hold on solid and stranded conductors, can be screwed down to a backer panel for organisation, plastic insulator is not load bearing (its just an insulating enclosure over the solid copper bus bar and copper screws & nuts), and the ‘end to end’ joining makes for visually easier tracing.
      Downside is they until you have screwed down to clamp the wire in place you need a hand to old the screwdriver, a hand to hold the wire into the terminal, and a hand to hold the terminal.

  4. I remember discovering these at my local “home depot” and using them. They offered a big advantage over wire nuts in a crowded outlet box because of their size and shape. But I generally reach for good old wire nuts.

  5. Keep in mind, what you can test on your work bench in a couple of hours has no real bearing on a real world, permanent installation. I have seen properly fixed wire nut junctions in the field that are 40 years old and going strong on 30A 240V circuits. I have also seen poorly done junctions that turned into melted copper and carbon residue in less than a year. Weathering and oxidation are the real test. Maximum surface contact between the leads and pressure deformation of the copper to block out moisture and oxygen ingress are the key. There have been many “crimp” connector related posts here and one of them did go into the physics involved in making a reliable, permanent connection (https://hackaday.com/2017/02/09/good-in-a-pinch-the-physics-of-crimped-connections/),
    and the same physics are true for any type of connection.
    I am not as confident of these lever type connectors when it comes to surface contact, and the ability to deform the copper, and would only use them where low current draw and limited life span are guaranteed. Flat, spring steel plates against a round cross section wire(no copper to copper, as well), which is all held in compression with the strength of plastics, does not inspire confidence.

    1. The argument isn’t that they’re superior to a properly installed wire nut, but that wire nuts are a lot easier to *incorrectly* install.

      In any case, you’re complaining about explicit bench tests because they don’t compare to your intuition about something you’ve not actually used yourself? Yikes. There are countless successful and safe installations of both kinds of connectors, they don’t need to be treated like a sports team.

      1. If you’re confident that you will never exceed the amperage ratings, and you have a promise from mother nature that she won’t ever exceed them for you, whether by moisture or organism (you’d be surprised how many amps some creatures can draw before disintegrating!), then you go ahead and raise your family with those in your walls.

        Intuition? Ah, no. I have actually used them. they make a great, quick connect for testing things.

        I’m not complaining about the test, I like watching bench tests. These connectors have their place. they’re easy to use, and they are easy to disconnect as well (although, why should that even be a feature if you want a permanent junction inside a wall?). I just don’t want people who have little or no experience with home electrical wiring to think these are totally fool proof. They will never consider how many amps their collective appliances are adding up to, or how many amps the circuit in question was rated for in the first place. there is just no substitute for two copper leads in contact, with no other metals between them, compressed together with a surface contact equal at to least the diameter of the wire. If there is to be any hot spot, I want to find it at the appliance (where there is hopefully a fuse), or at the distribution panel, where I can easily detect and remedy it. It’s no fun finding faults hidden behind walls, especially when the walls have already been carbonized.

        When I was a kid, the apartment building next door caught fire. Then one day, the building behind us caught fire. Then one night, the other end of our building caught fire. It makes it a little hard to sleep, not knowing what’s been done behind your walls.

        In my perfect world, there would be three solid copper buss bars around the perimeter of each room, seamless, of course, and 50kW on demand I think, should do. Then I could weld battleship anchor chains in the living room while the wife is enjoying the Olympic size hot tub, with the A/C running full blast, and the kids are riding bumper cars (dodgem’s) in the basement, and still be able to sleep at night. I can dream, can’t I?

        1. Your fears are completely misplaced. These connectors are standard in electrical wiring in houses of many countries, and their reasons in those standard houses are designed to match the circuit limits in which they are used.

          And in terms of idiots not knowing what they are doing they are far superior to people attempting to join wires with nuts, something which is done poorly very often.

          If I did my own wiring I’d take either option (actually I use wagos for easy modification and expansion which sucks with nuts), but if someone else did the wiring then I’d hope they use wagos for the peace of mind they offer in their ease of making a connection correctly.

    2. Can’t decide if this is a troll post or just stupid.
      Where did you exactly saw that the plastics is keeping the connection pressed together? By this logic wire nuts are the bad ones, because the newer ones does not even contain any metal, they are just a plastic cap to keep the wires together. That can melt too you know right?
      Also bench tests are perfect to quickly spot low quality components. If they fail the bench test then they won’t be reliable in the real world use either.
      But someone who hates anything what’s not commonplace in the USA will immediately try to make anything other than wire nuts look bad.

      1. Even on good wire nuts with steel coil, the nut is just a cap, but never rely on it to keep the wires together. That’s the thinking that leads to bad junctions. With or without the spring, it’s the oxidation between the copper leads that causes the heat that leads to failure.
        The copper leads should already be tightly twisted and holding together on their own before the wire nut goes on. If you don’t have time for that, you should be using a bell crimp instead.

        1. Seems like your mind is set on “wire nuts are the ultimate solution there is nothing better, i have seen 40 year old ones still functioning, you can’t prove me wrong because i will not listen”. Sorry, but you are coming up with worse and even more worse arguments.
          Keep twisting your wires then.
          I guess wire nuts are one of those US only things, similar to the imperial system. If somebody does not think its THE ULTIMATE SOLUTION then US guys must immediately attack it.

          1. There is no Ultimate Solution. I pick the right part for the job.
            These things are nice when I’m planning around on hobby projects. I use wire nuts when I do home or commercial electrical work. For industrial work I switch over to terminal blocks. ( I personally love gate style terminal blocks). For Automotive, I solder and heat shrink.

            Wire nuts can sometimes be a pain to use but they take being smash, pulled and all other sources of stress much better then push in or lever style connectors. Since I’ve had to hunt down open connections from wagos after cramming them in a box, I don’t use them. (Cramming ~ 6 connections of 3 wires each in a 4×4 inch box)

            Of course a good terminal block or Soldering makes a much better connection then wagons or wire nuts. Terminal blocks just need room and soldering is time consuming.

    3. It’s not flat steel plates. If it was, the wire would pull out with very little fight.

      Check this: https://youtu.be/n8gLG6c-iKc?t=60

      Both the top and bottom of the wire are engaged by the punched corner of the metal stock. It’s got quite a good “tooth” to it, and if you rig up enough leverage to pull the wire out, you’ll see the scrapes on the wire from how the metal piece grabbed it. Try that with a wire nut, let me know how it goes.

  6. I use WAGO connectors exclusively for semi-permanent connections (read: which might have to be changed in the future) for low voltage museum exhibits. The ease of use being reason #1, but also I had knock-off connectors that did not work reliably. They did not catch fire, but some of them made for intermittend connections which were painful to troubleshoot. For me the extra overall cost is negligible since an extra hour of work is much more expensive than 10 WAGO connectors. Ease of use + ease of mind = priceless.

  7. If you still join your power lines with wire nuts, it’s time to educate yourself on the lever wire connector. With this innovative and simple method of cable splicing, you may unite electrical wires in two simple steps while maintaining safety and security.

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