HN Theater @HNTheaterMonth

Cant believe I watched the whole thing.

I love vids like this - as its a good thing to have an understanding of how all things around you work.

Also, There are two ltypes of dishwasher owners: Those who pre-rinse things that fgo in and those who dont.

I ALWAYS pre-rinse everything. there are times when I use the dishwasher as a dish-rack and wash things by hand and just put them into the open dish-washer to dry... I prefer this to having anything on the counters.

---

I have a set of LG washer/dryer which are wifi capable...

I have yet to find a reason to connect them, even though I have a wifi extender node plugged into the same power as the washer.

I do have "smart" lightbulbs in every socket in the house and can control them all with alexa and/or the Feit app...

I use it all the time, and like to be able to set every single light in the house to whatever color I want. So Ill often set the lights to "Firebrick" which is the most calming at night.

https://www.smarthomeexplained.com/alexa-smart-light-color-n...

and I like to say "Alexa set all lights to firebrick" and every single bulb in the house and porch turn red....

But I guess Ill have to connect the washer and drier to wifi and see what added value I might find there...

FYI this is also a great vid by that guy on power plugs.

https://www.youtube.com/watch?v=udNXMAflbU8

Wrong on both accounts. Technology Connections spent a while trying to figure this one out and did a fairly decent video: https://youtu.be/udNXMAflbU8

the tl;dw is "They're for manufacturing purposes" -- Alignment for when you're injection molding around them. Any other use is entirely secondary. NEMA sockets don't have any mechanism to hold onto the detent.

⬐ couchand

Heavy equipment often has a lock through designated holes in the plug. But usually not wall warts.

⬐ solarmist

Sure, but that was aftermarket, not a design consideration.

⬐ indrora

Nope. That hole is, similarly, only for manufacturing positioning. It's also potentially dangerous to attempt to thru-plug lock out a device: An unsuspecting individual could jam it in anyway and suddenly potentially have the other half of a phase going through them if a receptacle is loose enough or they jam the pins in.

Under OSHA 1910.147(c)(5)(ii), lockout devices must be unique:

> Lockout devices and tagout devices shall be singularly identified; shall be the only devices(s) used for controlling energy; shall not be used for other purposes; and shall meet the following requirements:

Under OSHA 1910.147(c)(5)(ii)(C)(1), LOTO must be done such that a pair of bolt cutters alone would not simply bypass the lockout:

> Lockout devices. Lockout devices shall be substantial enough to prevent removal without the use of excessive force or unusual techniques, such as with the use of bolt cutters or other metal cutting tools.

McMaster-Carr offers only a single key-in-place LOTO for NEMA plugs, specifically 5-15 which clamps around the tines. This is a secondary use of the holes used for manufacturing but does not stop someone from giving a good solid tug, which can happen.

All other OSHA-compliant LOTO systems [encapsulate the full plug](https://www.mcmaster.com/loto-(lockout//electrical-plug-lock... or otherwise [bind to the body of the plug](http://lockoutmanufacturer.com/Pneumatic-Plug-Lockout3.html) in the case of circular connectors.

Note that OSHA LOTO rules do not stop someone from chopping the end off and putting a new connector on. They are intended to provide the broadest safety in the most common of situations.

⬐ couchand

Your McMaster-Carr link seems to be pretty good evidence that such devices exist.

FWIW I'd read c1 as stating that a lockout device need not be resistant to bolt cutters, as that would qualify as "excessive force or unusual techniques".

There is a more recent video from the same person (Technology Connections) that concentrates on plugs - specifically, why US plugs have holes in them: https://www.youtube.com/watch?v=udNXMAflbU8

⬐ jiveturkey

page 4 already so this comment is wasted.

But, this is the third time in as many months that a youtube video suggested to me has appeared on HN. It's clear that my interests (and YT suggestion algorithm) aligns with that of many HN readers.

It's _more_ interesting that HN is, in very small doses, infiltrated by megacorp algorithms. Promoted content subsuming independent discovery. Of course, 'subsuming' is too strong a word, so don't take it literally.

⬐ mindslight

So you can stick a pair of bare wires through them, of course.

⬐ Thetawaves

The holes exist to provide an edge capable of scraping off oxides on the contact, thus providing a (more) reliable low resistance connection.

⬐ jdlshore

That’s not what the video says. It says (and quotes the relevant standard) that they’re optional, and used for manufacturing purposes.

⬐ Thetawaves

Yes, this video is the undeniable truth. Anything this tuber doesn't know isn't real.

⬐ yladiz

The video isn't, but the standard is.

⬐ Thetawaves

The standard states they are optional, but provides no logic as to why a manufacturer would go to the trouble of punching these holes at great expense that are apparently unnecessary.

Look around at your high power appliances, exactly all of them will have holes in the prongs. There must be a reason don't you think?

⬐ SamPatt

The video contains a video showing exactly how the holes are used in manufacturing.

You seem to dislike people who create content on YouTube but this video seems well sourced.

⬐ Thetawaves

You are missing the point - people can make content on youtube all they want, but that doesn't make it correct.

⬐ Thetawaves

Just in case you missed it - high resistance connections particularly harm high power applications where the total power loss at the connection is proportional to the resistance multiplied by the current squared.

When you are operating near the threshold for the maximum allowable current draw on a single circuit (nominally 15A in USA), this additional power loss can make your device or product fail certification.

This feature is called self cleaning contacts. It is a well known technique in the connector world. Which this tuber is not a part of.

⬐ Keppl8R

1. If you were to take apart an outlet and look at the contact wipers that the prongs slide into, you would find that they have bumps on them. These bumps fit into the holes so that the outlet can grip the plug's prongs more firmly. This detenting prevents the plug from slipping out of the socket due to the weight of the plug and cord. It also improves the contact between the plug and the outlet.

2. Electrical devices can be "factory-sealed" or "locked-out" by the manufacturer or owner using a plastic tie or a small padlock that runs through one or both of the prong holes. Construction projects or industrial safety requirements may require this type of sealing. For example, a manufacturer might apply a plastic band through the hole and attach it to a tag that says, "You must do blah blah blah before plugging in this device." The user cannot plug in the device without removing the tag, so the user is sure to see the instructions.

3. There also is a small savings in raw materials (metal) for the manufacturer of the actual plug prong. Every little bit helps!

It has been reported that really old outlets used captive ball bearings and coil springs for the detent, but today it is done with a bump and springy copper contacts.

https://home.howstuffworks.com/two-flat-prong-plug-holes.htm

⬐ yladiz

I'm not sure if you watched the video, but if I understood your first point, he debunked that by testing it on a wide range of plugs (sure it's anecdotal but I doubt he has such different plugs from other people in the US). Apparently the plugs that actually do have the bumps don't fit in a way that is safe (either they fit accidentally and/or fit too far forward, meaning the plug, with the holes engaged, is partially exposed). The reason plugs don't slip out is because of friction, not because of the holes.

My suspicion was the third one, and I suspect that was the original reason manufacturers did it. It's likely done now because of the machines that make plugs expecting those holes.

⬐ rainbowzootsuit

I have a number of locking cord ends (outlets) for extension cords that do use the holes to retain the male plug via ball detents. They require you to push a button to release the plug.

https://www.homedepot.com/p/15-Amp-Stay-Plugged-Cord-Replace...

I've never seen anything else similar.

I'm curious on the design of "hospital grade" plugs as that wasn't in his survey and I know that they are designed for higher retention force than commercial or residential applications.

⬐ garren

None of the above.

#1 is ruled out as he takes apart a number of plug receptacles, from “cheap” to “heavy duty” and “commercial grade”, none of them sport the bumps you’re describing. He also points out that not all plugs have holes (using an ikea timer as an example), and observes that most plug-in receptacles don’t offer the kind of resistance one might expect if such bumps existed.

#2 and #3 are closer to the mark.

Apparently the holes are optional according to a standards body called NEMA (https://archive.org/details/NEMA-WD-6-2016/page/n24/mode/1up) and are generally intended for use in the manufacturing process.

“Hole in flat blade is optional, and is intended for manufacturing purposes only.”

See 13:30 in the video for an example.