15 amp fuse keeps blowing when hooked to generator

What kind of genset? If it is a inverter style it may not have a ground connection to the neutral. I have Hondas, they need to have a cheater cord body with a jumper between the neutral and the ground pins to lie to the systems in my rig.
There could be a 120 volt item in the rig that is wired incorrectly or has problems. Check between the neutral and the ground in your cord for continuity. It could be something like the refer 120 volt element.