DJ, what you use on the outside of the TIU probably has nothing to do with the melting which you mention and Alan discusses. That's a different issue. The original TIUs, Rev G, internally had wires soldered to the terminals. Versions after Rev G have crimped leads held to the internal ends of the terminals with nuts. The nuts loosen. I learned to take all post-Rev-G TIUs apart & check the tightness. Then I add atop the existing nuts internal start washers (star washers with the teeth facing the shaft rather than outward) and then a second nut as a lock nut. These are metric and I'm sorry, I don't have the size at hand.
I've never blown a TIU fuse--the external breakers always open first.
GRJ, you've convinced me that I erred and the Z-1000 breakers are indecent. Not as bad as the postwar ZW but not within the concept of decency. Once again I'll needle you to come up with a kit for an electronic circuit breaker as used in the PH-180. My guess is that it would be a better seller than the track detector. I'll order 8, one for each track channel and two for accessory circuits.
EJ, I still think for the average O-gauge layout 10-amps is too large. I also can't afford fuses; over tiem, the cost adds up. Checking the blow tables, it doesn't appear that fuses blow any quicker than thermal breakers.