Some of the extended tips seem to be that way because there's a glass fuse inside them.
Ed, I would have thought that the cig lighter wiring in my old Dodge truck would be beefy, but found that when I tried to start a 120VAC color tv with an inverter (engine off), the inverter would do a low-voltage shutdown.
Come to find out, when turned on the tv's auto-degaussing circuit would kick in and apparently had a large capacitor to charge. To get it working, I would start engine, plug all in, turn on repeatedly until the cap was charged and tv came on. Then I could move tv to egg and run it on extension cord from shut-down truck.