Why No power to fuse box?

This problem of no power to fuse box, must be traced back as far as your power meter.

You may be looking at a sub feed panel which could be fed from a main panel

so if this is the case you may have a tripped breaker or a blown main fuse.

If this is your only power box, then you most likely have a loose connection coming into the fuse box from your service meter. COUTION : This can be dangerous to check out, you should alert your power company as it may also be a faulty service meter causing this problem.