As a rule of thumb, fuses are rated according to the power rating of the appliance and appliances rated up to about 700 watts should have a 3-amp fuse.

The rated current of motors used in our mains powered blinds is 0.53-0.63 Amp, and they have a power rating of between 121-155W.

So, if you use a cable plug or connect up to 4 motorised blinds to a spur a 3 amp fuse will be sufficient to protect the cabling and motor or motors. If you run more than 4 blinds off a single spur use a 5 amp fuse.