Vias: to tent or not to tent

A question sometimes comes up concerning whether to tent or not tent the vias on a PCB.  Altium by default does not tent the vias.  There are several considerations.  The silkscreen can be visible over the tented vias.  The bare vias can be used as test points and for reworks.  The fanout vias for the BGA pads must be tented, otherwise shorts could happen.  If a via is very close to the SMT pad, it is better to tent otherwise it is harder to solder.  A large via cannot be tented completely.   If only one side is tented, it could trap flux and cleaning fluids. Then there is the subtle question about outgassing: a tented via might outgas.

Fuses in Parallel

Occasionally, we may need fuses in parallel to achieve greater current rating.  For instance, the Mini ATO fuses come maximum 30A; any more than that, two or more fuses are needed.  So are parallel fuses advisable?  Yes, it is better to stick with fuses of the same type and rating.   The current will not distribute precisely equally among the fuses.   But they will not differ two much before the self-balance nature of the fuse resistance.  The circuitry should be as identical as possible.  One company recommends, as a general rule, a minimum reduction in rated current of  10% for 2 fuses in parallel (20% for 3 or 4 fuses in parallel).