proper gauge wire from TT battery to TT itself?

[ranchosinvacas]

Battery cable size from battery to load center.
We have a 2014 145RB Jay Flight Swift SLX (Baja Edition)
The neutral or negative cable (white) is #8 gauge and runs from negative battery post to TT chassis, and then on to the load center. (breaker box)
The hot or positive cable (black) is also #8 gauge but it has an inline #10 gauge fuse holder with a 30 amp fuse connected between the positive battery post and the #8 gauge positive cable, and then on to the load center, (breaker box)
The battery and the #10 gauge 30 amp fuse holder were provided and installed by the dealer prior to delivery.
Is this fuse necessary? Is the #10 gauge wire too small?
What is the proper gauge wire size from battery to trailer?
Thanks for responses.

[RoyBraddy]

If you only have ONE battery installed i would say the smaller gauge wire is OK. The IN-LINE FUSE is necessary as a catastrophe cable fuse in case of a direct short to the cable. The battery is capable of alot of current for a short period of time and this fuse is there to protect the wiring from burning up in case a direct frame ground short...

If you was to install more batteries then I would go with 4AWG BATTERY CABLES...

Just my thoughts
Roy Ken