try more details like make and model and is it a macerator type with electric motor? meanwhile assuming its a macerator type and fuse you are refering to is in the unit itself then check the source of power it may be run from a 13amp circuit through a fused double pole switch and that's fuse may be the one that's blown.
Copy your post open another post question sheet and paste it in adding the type make and model the only other thing you need to add is the title.
BOB
December 2012