Adding an In Line Fuse to a 12 V Power Lead from a Vehicle Battery to a Trailer Connector
Question:
what size in line fuse should i use on a fused battery lead to a small pop up trailer with 30 amp service plug two 15 anp circuits?
asked by: Larry R
Expert Reply:
I assume you are wanting to add an in line fuse to a 12V power circuit running from your vehicle battery to the trailer connector on your vehicle. There are a few things to consider before adding an in line fuse to a 12V power lead to a trailer connector.
If your vehicle currently has a factory installed 7-way trailer connector, then the power lead will already have a fuse.
If you are adding a 12V power lead to your vehicle, then we typically require a 40 amp circuit breaker, like part # PK54540, or a 40 amp in line fuse. If your trailer is only rated at 30 amps, then you could just add a 30 amp circuit breaker, like part # PK54530, or a 30 amp in line fuse with a properly rated fuse holder.
I would recommend adding one of the circuit breakers that I mentioned rather than an in line fuse because the circuit breaker will automatically reset itself in the event that the circuit is overloaded.
I have attached a help article on routing a power wire for a trailer wiring harness for you to check out.

Products Referenced in This Question
Pollak Circuit Breaker - Cycling/Automatic Reset - 30 Amp - Straight Mount Bracket
- Accessories and Parts
- Wiring
- Circuit Breaker
- 30 Amp
- Pollak
more information >
Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket
- Accessories and Parts
- Wiring
- Circuit Breaker
- 40 Amp
- Pollak
more information >
Product Page this Question was Asked From
Pollak Metal 7-Pole, RV-Style Trailer Socket - Vehicle End
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- Plug Only
- 7 Round - Blade
- Pollak
more information >
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