Fusing Grand Central?

[SAMD51SERCOM]

I read the rather informative article on the Grand Central. https://learn.adafruit.com/adafruit-grand-central

The DC Jack is a 5.5mm/2.1mm center-positive DC connector, which is the most common available. Provide about 6V-12V here to power the Metro. There is no fuse on this connection so you can draw more current, up to 800mA between the 5V and 3.3V supplies, and 2A from Vin.

What I do not follow is how to properly fuse things if providing power through the DC jack? It looks like it can handle 800 mA if you are using the 5V and 3.3V supplies but I plan to feed it 12V through the DC jack and I would like to fuse it to protect the Grand Central in the event of extraneous power draw.

Also not completely clear how if the DC jack is the same as providing power from VIN or if that is different?

What value of fuse should I go with and should it be fast or slow blow?

Thank you for helping to clarify! Been using Arduinos for a while but the hardware side of this needs a bit more clarification!

[mikeysklar]

@SAMD51SERCOM,

You should be able to find a 12v car lighter plug connector that you can use in your mix which will typically include a 2A slow burn fuse. Kind of like this. This could couple to a female receptacle.

http://www.walmart.com/ip/2-1mm-12V-Car ... /688526892

Looking at the schematic it appears the major difference between the 2.1mm input and the Vin is a diode being available to the 2.1mm side which sounds safer to connect through than Vin direct to the votage regulator

371201C7-4FF7-4CCC-A730-B3816A5032BD.jpeg (337.37 KiB) Viewed 166 times

[SAMD51SERCOM]

I see the 1A diode there. Should I just install a roughly 1A slow blow right before the 2.1 mm power in DC jack then? If it consumes 2A slow blow, isn't that going to pretty much destroy the Grand Central by that point?

[mikeysklar]

I had read the 2.1mm jack as being able to handle up to 2A, but I see your point that the 1A diode size is mentioned in the schematic

Your plan to add a 1A slow blow before the 2.1mm connector sounds like the way to go.