Does Raspberry Pi 3b have polyfuse? If it does, under what conditions can it be 'blown'? I suspect my RPi 3b polyfuse to be blown, but I don't know what's causing it. I'm using an external HDD for booting into DietPi with its own power supply and after every day or so all the USB ports have no power hence RPi doesn't boot (but boots okay with SD card).

Can someone suggest why this happens and how I can prevent this from happening again?
Also, if this keeps happening will the RPi get bricked? Thank you!


2 Answers 2


The Pi3 has a 2.5A polyfuse. It will ""blow" if you pull more than 2.5A from the power supply. If you keep overloading it the fuse will eventually fail.



Does Raspberry Rpi3B have polyfuse?


Yes, and if it is blown, you can replace it.

replace polyfuse


(1) If Rpi3B's polyfuse is blown, Can I save it?

(2) Rpi3B+ Power Circuit Analysis - James Adams, rpi.org, 2018apr11


Appendix A - Rpi Polyfuse Schematic

polyfuse schematic

Appendix B - Rpi3B Polyfuse

rpi3b polyfuse

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