Power supply fusing

I bought a couple of junk rack mount power supplies that provided +15V, -15, +48V, and +5V. What struck me as odd was that the + and - 15 and +48 were fused via the "common" side before they were connected to "ground" rather than the "hot" side. Can someone tell my why?
Thanks!
Bruno2000

[quote author="bruno2000"]I bought a couple of junk rack mount power supplies that provided +15V, -15, +48V, and +5V. What struck me as odd was that the + and - 15 and +48 were fused via the "common" side before they were connected to "ground" rather than the "hot" side. Can someone tell my why?
Thanks!
Bruno2000[/quote]

This is on the DC side so there isn't any CE/TUV/etc rules to follow.

I think they figured that if you lost a rail, then it's better to lose all rails than have the other float away in some bad way, thus preventing the destruction of the electronics.

How many circuits have you seen where the electronics vaporized to prevent the fuse from dying?

-a