cRIO fuse??? 20 or 30?

[Jon Stratis]

From the data sheet, available in chapter 3 here: http://usfirst.org/community/frc/content.aspx?id=10934

3.5.2 Typical Application
** Always refer to FIRST rules for using this module in competition robots. The following sequence
describes an example application that may not fully comply with FIRST rules.
1) apply power to the DSC via J22 from a 5A (or larger) breaker on the PD
2)[...]

This typical application uses a 5A breaker... i doubt you'll need 30A for a FIRST robot.

Also, the worst that can happen if you use too small of a breaker - the breaker pops, and you put a bigger one in, after determining that it didn't pop due to a short or other hazardous electrical condition. The worst that can happen if you use to big of a breaker - your digital side car, and possibly anything attached to it, could go up in smoke.