My local hardware store has one of these signs. I managed a different hardware store about a decade and a half ago, and I also made a very similar one. (Mine was nicer, and routered out of a scrap piece of plywood.)
You would be amazed at the number of times we'd get asked that question. Typically it involved a story along the lines of, "Well, my wife started putting up her end of the Christmas lights at one side of the house, and I started putting up my end at the other side of the house, and we met in the middle, and..."
I don't understand how people need help making a cable like that. AFAIK It's a length of 3 wires wrapped in insulation, and two plugs. It's a hell of a lot simpler than ethernet.
Some older things might genuinely need that kind of cable, like a leaf blower or something
This would be perfectly safe provided nobody unplugged it.
Wired correctly this would just join the two hots together, the two grounds together, and the two neutrals together which is how they are already connected inside the outlet anyway, electrically speaking. But that'd only last right up until someone unplugged one end of it and touched the live prongs.
The two outlets could be on different circuits, if for example one of them is connected to a switch on a lighting circuit.
Then, the cable will be powering one circuit from the other. A circuit limited to 20A could draw 40A before blowing, causing damage to the wires.
Someone might do some wiring work on the lights, and shut off the lighting circuit, and still get zapped (though most electricians would test it before touching it, since breaker labels are rarely accurate).
There are many creative ways to die to a cable like this.
The two outlets could be on different circuits, if for example one of them is connected to a switch on a lighting circuit.
While this is technically possible by cutting the bus bars linking the upper and lower sockets, this is a duplex outlet and by default both sockets are internally connected. It's fantastically unlikely anyone would go out of their way to create the setup you described, which would also require by code for both circuits to be connected to a linked breaker so that if one is overloaded both circuits are tripped. Making one of the outlets switched would also create an extremely confusing situation for the user or building owner, which would inevitably result in a never-ending bitch session at whoever installed it in the first place, e.g. every time the cleaning crew plugs in their vacuum cleaner and this outlet "randomly doesn't work sometimes."
But then, if someone is running around with a ready-made double male mains cable in your building, all bets are probably already off.
Most people would use it to solve Christmas light screw ups which means there would be another male and sticking out exposed later in the line. Just as dangerous there.
Extention cords are dangerous because they are not always the right gauge.
People get cheap extention cords and try to pull more power than the cord can handle and it ends up heating the cord and causing a fire.
It's why a lot of things say "Do not use an extention cord! Plug directly into wall." Because they know someone is going to use a dollar store extention cord on a space heater.
Not because the space heater won't work with an extention cord
Most people care about plug type (low profile) or color more than they do the quality or gauge of the wire.
Anyways, this cord could be dangerous like that if the gauge isn't the same or thicker than what's in the wall.
Despite all the hate, I do have one of these. I used to have a box next to my furnace with a male end, wired up to the switch so that if the power went out for a longer duration in the winter, I could plug the furnace into the generator with an extension cord and heat the house. When the furnace was replaced, I was too lazy to wire up another. A friend who's dad is a master electrician told us that in an emergency, you could flip all the breakers in the box to off including that mains, use a male to male cable to plug the generator into a wall outlet and flip on the furnace breaker and the breaker where the generator is plugged in and power the furnace that way (so long as both circuits were amp rated the same).
Of course, it came with a disclaimer that he'd deny telling us this to the insurance company and a warning that "bad things would happen" if we somehow enabled the mains to the power company.
ah yes, a suicide cord. that's why there's warnings about them in every hardware store.
you can't stop stupid, but you can inform people they are stupid.
yes, it works in a pinch, but when you're cold and stressed when power goes out at 3am will you remember to plug it into the wall first? will you remember to cut off mains before you turn on your generator? will you remember to do the steps in reverse when power comes back?
I'm harsh because I've almost killed myself with one before, because I'm an idiot who (just like everyone else) thought, "I'm smarter than most people when it comes to this stuff".
get an interlock kit. save yourself and the lineman.
Also be warned that you must plug in any generator as close to the breaker box as possible. Outlets and their wiring far away may be underdimensioned for powering anything significant further away. Also be warned that everything you're powering together must be limited by the dimensions of the one outlet you're using. The wires don't know any difference between AC in or AC out. For example it's max 10A? Then that's your limit for everything combined.
In a local grid where the electric company actually allows you to feed back power it must also be possible to disconnect the generator automatically if your inverter detects the grid is down. Because of that these power companies typically only allow approved solar power systems to get connected to the grid to make sure it's one that will disconnect.
I saw a video on YouTube where a guy did plug a male to male in and guess what, nothing happened. He went on to explain that most outlets have a safety mechanism for this scenario built-in.
He went on to explain that most outlets have a safety mechanism for this scenario built-in.
wat? The only dangerous part of this scenario is when you only have one end plugged in and you have a hot, male plug. Unless you reverse one of the ends, the outlet wont react and if you do short it by reversing the ends, the Breaker, not the outlet will cut off the power.
Also, you also shouldn't have male-to-male cords in the first place.
It's a continuation cord. You see, the wiring works like this:
The receptacle is split on both sides.
The incoming power is double lugged on the bottom outlet.
The outgoing power (to continue the circuit) is double lugged on the top outlet.
You have to use the continuation cord to get the power from the bottom outlet to the top one.