12V Inline System Fuse

[_1nobby]

On my new to me TT, there was a 12V 30A fuse near the battery tray.

When I followed the 12V wiring under the trailer, I found the 12V electrical box with an additional 12V 30A fuse before the box.

Do I need both? These fuses are the auto-reset 2 post 30A style.

Seems redundant.

[RoyB]

The main reason for the FUSE at the battery terminals is to protect the wiring from a direct short to frame ground down the leg. The battery(s) can produce a very large amount of DC current for a short period of time... Could cause a fire from burning cables or the battery itself may even blow up which is a rare thing...

I had to change my 12V IN-LINE fuse vales when I upgraded to more batteries as my increased loads was more than the fuse value...

Roy Ken

[JesLookin]

I would guess that the 30 amp fuse is protect the wiring in case of a short. The 6 amp circuit breaker would protect the motor from overload. The motor would draw more than the 6 amps up until the breaker heated up enough to open the connection.

[BB_TX]

Typically the first line of protection is installed within a very short distance from the battery to protect in the case of a short in the line and overheating the wire. Don't know why they would have installed another in series with the first.

[myredracer]

Do you have electric stabilizer jacks? If so, Lippert specifies a 30 amp fuse and 6 amp breaker in series. The manufacturer of your TT (if you have the elec. jacks) may not have followed Lippert's specs. They didn't in ours.

[donn0128]

Actually what your describing is a 30A auto reset circuit breaker, not a fuse. Fuses are a one time item.
Do you need two? No, but I suspect one is to protect the battery, the second one to protect something else. Only way to know for sure is to disconnect one and see what does not work.