Yes! There is a video about this. Heat in spool of cord is trapped.
Free_Opinions@feddit.uk 5 weeks ago
Related thing about extension cable reels that many don’t know is that even if you need like 3 meters of cable you should still unspool the entire thing as otherwise it’s acting as a coil and creating resistance. Most cable reels have different ratings marked on them for when they are spooled / unspooled.
uis@lemm.ee 4 weeks ago
modeler@lemmy.world 5 weeks ago
Many years ago, my mother used the electric lawn mower without unspooling all the wire. When it finally shorted, all the plastic wire insulation was in the process of turning into a melty plastic soup. A Lesson Was Learned.
The reason isn’t resistance - it’s that the coiled wire makes an electromagnet that stores energy in the magnetic field. The alternating current in the mains switches 50 or 60 times a second. In each cycle the magnetic field is created, destroyed then recreated in the opposite direction, then destroyed. This dumps a lot of energy (and therefore heat) into the coil.
brown567@sh.itjust.works 4 weeks ago
The coil wouldn’t make a significant magnetic field because the cable has two wires with opposite current flow in close proximity
But when the cable is coiled, its ability to dissipate heat is less, so normal resistive heating can create higher temperatures
uis@lemm.ee 4 weeks ago
Inductance is not the reason here