What's the issue with these? They look as safe as any other fuse-less extension cable to me. As long as you have a fuse somewhere in the circuit, what's the problem?
A normal extension cord like we've all used has a plug at one end and a socket at the other, so you won't get killed by simply mishandling it.
I love this part of the product description:
"It Can Help Protect Your Family And Keep Them Safe"
Right...
Having said that, the longer Product Description With Every Word Capitalized explains the use case somewhat:
You've lost power and it will be likely be out for quite some time. But you had the foresight to have a generator and one of these cords. You plug one end into your generator and the other end into an ordinary wall outlet. Now every outlet on that circuit will be powered from your generator.
However, your normal fuse or circuit breaker will not protect you from an overload on that circuit, because you've just hotwired your generator into the "house" side of the circuit. So, as the description says, you may be able to power your refrigerator and some lights, but overload the circuit and you may burn your house down.
Also be sure to turn off that breaker or remove the fuse on that circuit. Otherwise you will be having some fun when power is restored!
Oh gosh, it gets even better. Check out the reviews on the Amazon listing!
Finally, I would like to thank the parent commenter for asking an honest question. Perhaps it sounded naive to some, but I appreciate a question like that, as it gave several of us a chance to explain the issues around this kind of electrical cord.
So the repair crew has the lines deenergized to replace that transformer that blew down the block from you except... surprise! they’re still live!
Or just very awake. You sissies. I've been buzzed by 230V AC so often... :-)
(Imagine picture of raised hair by van de Graaff generator here)
Male-to-male cables absolutely should not be made up.
Apparently some people make them for plugging caravans in to external power as a sort of hack.
In hindsight it was stupid to not have turned off both circuits anyway, I’m just glad I was wearing sneakers so the shortest path to ground was the junction box itself.
https://en.wikipedia.org/wiki/Residual-current_device
These are usually built into the electrical outlet (or one outlet may provide the GFCI/RCD for several connected outlets). A whole-house RCD as described above would be a wonderful thing.
If the “test” button is ever unintentionally pressed, maybe from some furniture or whatever pressing against it, then your whole circuit goes down. But the breaker box shows no fault, and now you get to waste the afternoon inspecting every inch of wall space for an upset outlet.
RCD breakers really are a wonderful thing though, I had my second small fridge knocked out because I had accidentally hit the test button of the outlet near the kitchen sink that the dining room outlet was fed from - having it at the breaker makes it a whole lot less confusing and removes the searching for the protected outlet conundrum.
More recent versions of the NEC require that the breakers used for both hot legs of such circuits be linked so turning one circuit off also turns off the other.
Common neutrals on residential branch circuits have largely fallen out of favor for new construction due to requirements for GFCI or AFCI protection on most circuits.
Related but different, AFCI breakers are now required where I'm at in bedrooms and similar spaces where you wouldn't expect appliances to be plugged in.