How can I stop the fuse from fusing in my Golf?

My 15 amp fuse in my golf for the accessories (cigarette lightert, radio etc) in my golf keeps fusing each time a switch on my car. I insert a new fuse when the car is off, and I can turn on the radio with the ignition in the off position, but as soon as I turn the ignition on, the fuse fuses.

What can I do???