I actually posted about this on the Raspbmc forum here
as well but feel free to ignore that and continue here if you prefer.
My UBEC is indeed a 3A one and I'll be using a 5v/4A PSU which came with the hub.
Can I can use GPIO pin 2 OR 4 for +5v and 6 for GND? The UBEC has the two lines going into adjacent holes on a header, so if I can use pins 4 and 6 I can just plug it in without modifying.
The only thing I'm plugging into the Pi is a 16GB USB stick (and SD card) with all the other devices plugged into a powered hub (7-port but three are on the inside of the case and it's likely only one of those will be usable due to the case layout) , which will be connected to the other port via the data lines only. Would a 2A fuse be good between the UBEC and the GPIO pins or should I use something lower?
be a suitable fuseholder? I could get something like this
instead but they look like it would be fiddly to replace the fuse.
For the fuse, would these quickblow ones
(available in various ratings) be suitable or would this
(only available in 1A) be better?
I'll probably have a dual DVB-T tuner, RF remote receiver, WiFi dongle, Wireless keyboard/mouse receiver and occasionally another USB stick plugged into the hub and possibly in the future a USB HDD, so assuming the Pi takes 1A max (I know it's probably less but I'm being generous), that would leave 2A from the UBEC or 3A direct from the PSU. So with all those devices I'm not sure whether the possible benefits of feeding the Hub from the UBEC outweigh the reduced ampage.