regardless of whether the machine is on a spin, if the heater has an earth leak, it will trip the electric
the only way to be sure is to either disconnect it, or test it properly with a megger
if you choose to do either, make sure you unplug the machine before doing any work
theres only usually 4 reasons for blowing a fuse!
1 > broken wire somewhere (v v unlikely)
2 > wash heater down to earth
3> dryer heater down to earth
4 > motor down to earth
like i said, power off if investigating