They dont look or feel isolated, like ones inside a headphone cable
They're called enameled cables, they've got a thin layer of insulation which prevents them from rusting or shorting.
To add, enameled wires are also used in motor windings and old CRT monitors (deflector windings). The easiest way to identify it is to scratch with a knife or burn a small portion of the wire to see if the enamel separates.
What does it look like when the enamal seperates vs a non-enameled wire?
Slightly brighter and shinier. The enamel gives it a slightly darker matte finish. More importantly though, the peeled/burned enamel looks different from copper.
I created an account just to answer this. They can short. We had a string of these, and it shorted and nearly caught the tinsel on fire. They weren't man-handled, in fact we were extra-careful with them, because they were so thin and fragile-looking. These are dangerous. Do not use them.
The power supplies feeding these are typically .5A at 5v so they can't draw more than ~2.5w. Is that really enough to generate sufficient heat to start a fire? Maybe if they are wrapped around something incredibly flammable?
Is that really enough to generate sufficient heat to start a fire?
In case of a short circuit, yes, more than sufficient
Welcome
Thank you. :)
There is a nonconductive coating on the wire that also prevents it from oxidizing. The wires can touch, but if the coating isn't scratched it won't short.
Some fine grit sandpaper will reveal the metal so you can solder connections.
will also see it sold as “magnet wire” (for winding your own electromagnets) and the heat from your soldering iron is usually enough to melt through the enamel varnish
That's generally not recommended as a way of stripping them though, since the coating is often made of polyurethanes, which release alkyl isocyanates (highly toxic) when heated strongly. While a small amount in a well-ventilated area might not be enough to give you any problems, if you get too much it is very bad. The organic material will also impact the ability to solder. Better to scrape it off first.
They are all insulated
Yeah, those kinda puzzled me as well. They didn't look like they're varnished, but I suspect I could be wrong about that. After all, they do work, lol 😂.
"Never change something that works"
It works for now, but the reason most wires have a rubber-like insulator around them is that it takes very little to Crack or abrade a thin coating such as this and turn it into a fire hazard.
I'm surprised a product with such a small safety margin is allowed for sale.
It works with 2 or 3 AA batteries, not that much power
I once accidentaly shorted the connector cables of a battery pack with 4 AA batteries. It very quickly generated enough heat to set the insulation of the cable on fire.
Don't underestimate short circuits!
Still enough to generate heat for something like dust to catch fire if it shorts
It's usually a thin resin/epoxy coating so it's transparent and has a similar slick feeling as the metal would. The same coating can go over the leds so it's fully waterproof.
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