fmstrat@lemmy.nowsci.com 2 weeks ago
The longer the cable, the thicker it needs to be to carry the same amount of current without getting hot. This is due to resistance (Wikipedia does a good job with the details). Basically:
20’ cable be long and thick.
10’ cable be short and thin.
10’ + 10’ cables be long and thin.
Long and thin = heat then fire.
That being said, put an LED light bulb at the end, no problem. Put a gaming PC on the end, problem.
ArbitraryValue@sh.itjust.works 2 weeks ago
I don’t think you’re right about heat. Two cables in series have double the resistance and therefore double the total heat generation, but that heat energy is split between the two cables so each one does not get hotter than if it was the only cable.
fmstrat@lemmy.nowsci.com 2 weeks ago
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Current and Voltage don’t change, but resistance does (between cable types)?
Aqarius@lemmy.world 2 weeks ago
What are you talking about? Current absolutely changes! Your own formula requires I=V/R
fmstrat@lemmy.nowsci.com 2 weeks ago
My mispeak there was voltage.
kevincox@lemmy.ml 2 weeks ago
Yes, you will have double heat output due to twice the resistance which causes twice the voltage drop and more or less the same current. But this heat output is spread across twice as much wire, so unless the extension cables are coiled together on the ground each will heat up the same amount as a single one would.
fmstrat@lemmy.nowsci.com 2 weeks ago
These changes are not linear with extension cords, as the gauge variance is less than changes in length. 100% longer doesn’t mean 100% thicker. Also the heat does not just occur in the wire. Whatever is at the end of that cord has to work harder due to the voltage drop, and harder means hotter.