Experimenting With 20 Meters Of Outlet Adapters

You may have seen some of the EEVblog dumpster dive videos, where [Dave Jones] occasionally finds perfectly good equipment that’s been tossed out. But this time, rather than a large screen monitor, desktop computer, or a photocopier, he features a stash of 283 electrical outlet double adapters that he found last year. He decided to perform a test in the parking lot, connecting all 283 adapters in series.

Using a pair of power meters and a 2 kW electric heater as a test load, [Dave] and his son [Sagan] measure the loss through this wild setup. It works out to about about 300 W, or roughly 1 W per adapter. He did a follow-up experiment using a FLIR thermal camera, and confirmed that the power loss is reasonably uniform, and that no single rogue adapter consuming all the lost power. After a back of the envelope calculation, we estimate this chain of adapters is about 20 meters long, making this whole thing entirely pointless but interesting nonetheless. Stick around until the end of the video for a teardown — they’re not as cheaply made as you might think.

[Dave]’s crazy experiment aside, we do wonder why someone had so many adapters to throw away in the first place. What would you have done with 283 adapters — left them in the dumpster or rescued them?

100 thoughts on “Experimenting With 20 Meters Of Outlet Adapters

  1. “we do wonder why someone had so many adapters to throw away in the first place. What would you have done with 283 adapters ”
    To run 24 devices from a single outlet, obviously.
    (If I am right that the geometry only allows 1 extra outlet per layer.)

    1. Only because some would physically block others.

      If you chain them like in the video you get a silly long outlet with hundreds of sockets. Each connector adds two sockets while consuming one.

      A single power strip to start could divide the length of this comical silliness.

      1. yeah, that’s more like 200m of 14AWG for a 300W loss at 10Amps… so definitely better than the adapters, but these have a surprisingly low resitance at 0.01Ohms, they are definitely good I’d say…

  2. Don’t know about Aussie power but here in the states those splitters are typically just bus bars. Wouldn’t cause power loss but the sheer weight of them plugged into an outlet would make it unsafe.

    Would be fun if they were smart adapters.

    1. Solid bars or not, there would still be power loss. Any length of wire has some resistance, even if it is low, and this will always result in some wasted power over the resistance of the wire.

      These would also have relatively high impedance from the connection points. For a high draw load like the space heater he is using, even a straight busbar for the same length with no connection points would still cause power loss.

      1. You would have at least a magnitude of resistance more just in contact area per connection compared to what’s onside. It’s very hard to get a solid connection (broad surface area) with out a forced bolt down connection. At one watt per at full load does tell you something about contact resistance. Mind you it’s in Australia,where the line voltage is 240v. With 120v here in NA, plugs get nice and warm, more than 1watt at full load.

  3. ‘What would you have done with 283 adapters?’

    Chain-measure ’em in a parking lot
    Chain-measure ’em in a parking lot
    Chain-measure ’em in a parking lot
    Early in the morning

    1. Put ’em all in series with some meters on ’em
      Put ’em all in series with some meters on ’em
      Put ’em all in series with some meters on ’em
      Earl-eye in th’ morrrrning

  4. He connected each to the second outlet. Need to repeat using the first outlet of each device (so connection is prong to prong, without going through the wires). Know how much loss is the wires and how much in the prong to fork connection.

  5. Certainly not a waste of time as some have suggested. Most homes probably have several of these in use and the energy wastage can add up. I had not realised that it could be so high.

    1. I have high quality wall sockets in my house, but even so the plug on cheap extension cords will often get fairly warm when pulling well below rated current through them. Copper oxide is pretty resistive.

    2. it’s around 1W at close to 2kW running through… that’s around 10mOhm for a single adapter
      TBH, these adapter are quite good quality and they all seems to be quite equal without bad ones in the middle…

    1. I ha e wondered the same thing. The amount of stuff he gets would require some serious time diving through the dumpsters, at least around my neighborhood. And he seems to have better things to do, well, based on the above. Maybe not. Maybe he just befriended the local trash guys and gets a tip whenever something good is around

      1. He’s explained it in past videos as being located in a complex with a few tech businesses. I cannot for the life of me remember which video it was.

        I work in an airport and recently liberated a lot of high quality brand new gauges, sensors and hardware that must’ve lost their certification paperwork from the dumpster. My home shop projects don’t require certificates 😅

  6. I helped a friend narrowly avoid a fire the other day. They had hooked two fan heaters to a 5A-rated extension cable, one of which was connected via a 10m cable reel.
    She’d blown all but two fuses in the 5A 4-way extension and was wondering why it wasn’t working.
    When I unplugged it to check what she’d done, the plug on the reel was almost too hot to touch.
    I had to explain to her that plugging an extension into an extension and having two 2kW heaters running from it was NOT a good idea and that she’d narrowly avoided burning the house down.
    She didn’t thank me for stopping her from getting burnt and crispy either. Next time she might not be so lucky.

    1. I worked as a contractor for a (major Japanese electronics company) a few years ago. They had numerous electronic and electrical engineers on site.
      I came into work one day and found an extension cord reel marked “Do not use!”
      One of them was using it and didn’t completely unreel it. It overheated inside the reel and let the magic smoke out.

          1. it’s mainly for pure ohm and heat dissipation reasons… a 20m one at 10amps would probably have to dissipate in the 10W range… not much but when coiled it can head up until the insulation can melt…

          2. The whole “AC electromagnet” thing is very wrong. I hoped HAD-readers know better … It’s essentially a bifilar wound coil, and because the current returns in the conductor pair in the cable, there is absolutely no induction going on. It’s purely resistive heating.

    2. When I was a young engineer, my senior office mate told me a story about a fireman friend who had made a recommendation about home outlet boxes. The advice was to put a couple of firecrackers in each outlet box — this was back in the day when some houses were still wired with aluminum. I was told that this technique was effective in at least one night home fire in waking up the family, giving them a little more time to escape than had the depended on the smoke detector alone.

  7. If those were the typical “cube” taps in the United States made in China some would not fit in all the way, some would fall out freely or fit loose, some could melt down, and the power wouldn’t even get to the end without shaking and wiggling to have it come on.

    1. Honestly… China has nothing to do with it; there are plenty of cheap products made in all countries. All corporations are profit-oriented; shave a few cents off here, and force an ancient standard there, and viola, planned obsolescence.

      But, you don’t really care about that… and frankly… too many people have so much going on in their lives to sit down and research 50 products and companies. There really is no one country that does everything well. I mean, for ****s sake, my brother worked at the Harley Plant out here in Pennsylvania, and you don’t want to know how how much jank goes on. I spoke directly to someone who was at the engineering plant, we discussed the issues with the drive bands and valve bodies on the 4T65-E and 4L60. She was so disappointed with how little these large corporations care about making something last… I digress as this is not the topic at hand. It needed to be said though, and I won’t budge on that

      The fault does just lay with the NEMA standards we use for residential outlet plugs/sockets. The problem is now, we kind of porked ourselves and made it very difficult to change to better connectors (we sure as hell know the billionaires can’t lose even one drop of their wealth for anyone if it doesn’t mean they won’t profit from it later; they’d rather profit off the average joe to upgrade all of their appliances, new or old).

    1. Assuming they’re all in perfect condition you’re right but it’s not a crazy theory that one or two of them could have been slightly defective and had a higher loss than the rest. Say one of them had a loose internal connection and was generating a lot more heat than its neighbors. If that happened with two that would have less than a 1% failure rate.

        1. I’m assuming you’re not trolling and just confused.

          There are two wires parallel to each other in each adapter but those are small parts of one series circuit. In reality this is an AC circuit but pretend it’s DC for a moment. Current would flow in one continuous loop. Start from the source, into the positive side of adapter 1, through the bus bar, through the outlet to the blade of adapter 2, so on until it gets to the appliance where it turns around and enters the negative side of adapter 283 and starts making its way back through adapters. At no point does the path of the electricity branch, so no parts of the circuit are in parallel to each other, so it’s a series circuit. Switching back to AC means the direction of the loop keeps changing but it’s still one loop with no branches.

        2. Think about the path of current flow. It’s one continuous loop that starts at the power source, flows through one side of each adapter, through the heater, and back through the other side of each adapter. At no point does the path branch into two paths so no parts of the circuit are in parallel to each other. So it’s a completely series circuit.

          1. You’re both right. 0It’s two resistors in parallel and one bridging between them, then two in parallel and one between them, etc, with each side in series with the same side in the next stage. The two in parallel are almost zero ohms, the one between is almost infinite ohms.

            | |
            [9999M] [9999M]
            | |

          2. These are double adapters, putting a voltage meter at one end does create a series circuit..

            But being double adapters you can put a load on each secondary socket and still get full supply voltage (minus voltage drop / loss) this could not happen if these adapters were connected in series.

            Connecting them in series would mean you would connect the Active into the Active pin of adapter 1, bridge out the Active and neutral female sockets on the second outlet, then connect the neutral pin of adapter 1 to the active pin of adapter 2 and so on.

            So the active supply would connect the active pin of the first adapter and the neutral would connect to the neutral pin of the last adapter..

            The article should have read that the adapters where ‘connect one after another’

            Get the terminology right when working with electricity is rather important

    1. I once (ONCE!) converted a female 400V 125A 3phase connector to male to plug a generator into a ship’s outlet. I immediately detransitioned it when done as it was very unsafe.

    2. What did he do or say against trans people? I’m not defending him. I have my own reasons for not liking this guy but a quick googling didn’t turn up any evidence that he’s a transphobe.

      1. From the other reply to it, I’m assuming it’s sarcasm due to a post about how you shouldn’t turn an extension cord into a male-male to plug a generator into a house outlet.

    3. Okay, so I googled “Dave eevblog transphobic” and the only relevant results I get is a reddit comment saying they’re glad LGR, Dave, other youtubers, etc are proLGBT.:


      And I get this tweet from Dave upset that people are making ‘trap’ jokes in his youtube video comments because he used the word trap in the title:


      I think you’re way off base here unless you come out with something really damning.

      1. Dave is a very respectful person he has worked with trans YouTube Fran Branch frequently, friends on sceen and offscreen, never once making off colour remarks or even treating her as anything less than the woman she is.

        1. Why does it matter if he does or does not work with a trans/gay/etc type of person? What does this have to do with anything? This “let’s insert sexuality into everything” mentality is really getting out of hand.

  8. Here in Australia the use of such adaptors in business is banned I remember binning 80+ adaptors a few years ago when the laws changed. They likely held onto them but decided to bin them after a few years. As they are l now as favourable as herpes in business.

  9. I’ve never liked Dave. But this one takes the cake. 230 microA of capacitive leakage… sounds reasonable. But that’s not 54mW: Almost no power is being transferred. The meter clearly says 54mW, so this is a case of Dave not knowing what his meter is displaying.

    With 8.6A dropping close to 10V, the resistance of his feeder circuit is about 1 Ohm. So that capacitive current will cause 52nW of losses in his extension cord. Wow!

  10. There’s far more useful information here than initially meets the eyes. The lesson here is “EVERYTHING HAS A LITTLE LOSS!”. One interesting thing to look at here is what happens if you let this monstrosity go for a period of 3-5 days. My prediction is that something will eventually catch fire within the 3-5 day period. This highlites the idea of usage duty cycle. Most electrical products are not able to perform at their highest spec for a constant 24-7 period of time. Temperatures eventually builds up and a fire will start. When an electrical device is operated 24-7 the current spec must be de-rated to prevent an eventual fire.

  11. Does heating up cause enough resistance that the current is limited enough to keep a fire from starting? Different scenario, but with power adapters that step down the voltage, if the secondary wires are small enough gage, you can short them out and it will never get hot enough to start a fire, much less melt the plastic or wire coating.

  12. I miss the angled adaptors, where the plug would be at about a 45 degree angle to the socket.

    Unfortunately, connecting them in a large circle, Ouroboros-style did not give me infinite power.

  13. Ugh. Let’s not give oxygen to this guy. Aside from many of his videos having overt sexism and racism in the, he doxes people.

    People like Dave Jones should not be welcome in our community. He’s the reason people get pushed away from electronics as a hobby and as a vocation.

  14. @kuro68k I’m not a fan of him, and I find the Aussie accent rather.. unpleasant, but I don’t recall him ever being noticeably racist or sexist really, nor do I think I’ve ever seen him dox people.
    Mind you he is very active and has his forum so perhaps I just missed it amongst the deluge of content?
    Or perhaps you are talking nonsense because of some personal beef.
    I’ll have to wait and see.

  15. Serious question. If I wanted to plug in 100 digital alarm clocks at the same time (the small wood grain non-radio clocks). Would a series of power strips be safe like in the above example? Could it only be powered for a short time? How do they keep all the tvs running at a Best Buy (oh God I almost said circuit city).

    1. It depends on the power supply. If they’re only 5W each, 100 of them is only 500W, which isn’t all that much power, really. less than the test above. However, switching power supplies have a significant inrush, which could trip breakers if you turn on all 100 at the same time. You might want to turn all the power strips off, plug it into the wall, then turn them on one at a time from the wall to the end, so only a few turn on simultaneously.

      Stores generally just wire in lots of extra circuits and outlets. If a 60″ TV uses 200W, you are limited to no more than 10 on a 20A breaker. During inspections of commercial facilities, the fire marshal prohibits chained power strips, and will insist that they only be plugged straight into a wall. Alternatively, you can do things like buy permanently installed metal raceways with outlets every 6″, like https://www.legrand.us/wire-and-cable-management/raceway-and-cord-covers/plugmold-systems/c/lgnd091208 . But in practice, commercial display cases/shelves will have optional outlets and cable stowage to make everything sleek.

    2. Serious Answer:

      The first one should be fairly easy to understand: Never overload the circuit breaker. Most appliances limit themselves to about 1500 watts for this reason. Throwing a ball park figure of about 2 watts per clock, that would be about 200 watts total for 100 clocks. Pretty safe here.

      Part 2: It is recommended that you NEVER daisy chain power cords … but I do it all the time anyways. You just don’t want to do so when drawing lots of current. I think your pretty safe at 200 watts.

      Part 3: Depending on size, TV’s will draw about 50 to 200 watts each so my guess is that Best Buy is NOT daisy chaining power strips since they will push up against the 1500 watt limit to easily. I’m guessing they have LOTS of circuit breakers instead

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