I run the same setup with a 15A fuse in the power feed. I'd put in a 15A fuse and call it a day. Worse case scenario would be you're riding down the road and start to smoke! The Gerbings gear is guaranteed for life anyhow.

 

My second liner had an intermittent short that might cause a fuse to blow after 15-20 min. at a time, so it is possible. This was discovered on a trip to AR that was destined to include some cold riding, so I needed the liner to work. As dumb as this may be I tried a 20A fuse after blowing probably three 15A fuses in the first hour of riding. That fuse lasted the rest of the trip without further issues, after which time I sent the liner and gloves in to Gerbing. They isolated it as a problem with the liner. My first liner had a short in the glove wiring, and that would blow a 15A fuse immediately whenever the gloves were connected. I'm on my third liner now and it worked fine throughout last winter, so I'm hopeful my problems are over for a while at least. I was beginning to feel cursed.

 

I had that happened on a freezing cold morning then I changed mine with a 15A circuit breaker to have a peace of mind next time it takes crap.

 

The Gerbing harness's that came with my stuff all had 15 amp fuses. Gerbing's site has the amp draw of all their equipment.