How To Add More Electrical Lines To My Car

Author: JRAutofix  Date Posted:1 July 2020 

Adding a fuse block to your 12V 24V system might bring safety and convenience to your installation and will allow you to run more accessories.

Depending on how many electrical accessories you want to add to your car you might first consider if you require a dual battery system installed.

If  it’s only a few small accessories your main battery should be enough.


Now the question is how to do it safely that you don’t run the risk of damaging your main car electrical system and keep everything tidy.


You want to avoid to have to many lines coming from the battery  , as often done, is running each accessory directly to the battery with an inline fuse.

The problem with this is you end up with messy wiring with the potential for things to rub and short out. It's near on impossible to find which fuse you're after if something goes, and you are using longer wires to cover all your need.


Instead one cable to a fuse block positioned closer to your electrical accessories would look a lot leaner and organised and it will makes adding more accessories later a pain-free process.


What you need to know

With all your accessories running through the one cable it's going to see a whole lot of load on it. Inline fuses and off the shelf wiring looms are never going to cut it.

Fuse blocks have fuse output that accepts up to a 30A, up to 100A combined.


There is different types of fuse block on the market, some provides fused distribution of your positive terminals, as well as distribution for the negative wires. This is especially handy in a boat or caravan which may not have a chassis-ground type system.



Others provides fused distribution of your positive terminals and with negative wires from accessory going to chassis-ground.



 They sses standard automotive blade fuses.

They come with integrated “fuse blown” indicator LEDs. The clear plastic cover allows you to quickly fault-find without disturbing your wiring.


They are suitable for use in 12-24V systems and Uses standard automotive blade fuses.


Reasons for wirring protection:

  • A fuse interrupts excessive current (blows) to prevent damage (overheating and fire).
  • A circuit breaker to protect against shortcut



fuse block can be used in not just cars and trucks, but also RVs, watercraft, motorcycles, and any other 12V or 24V system.




Determining which fuse to use:

  • Determine the wire gage you already have by locating it on the package or simply by measuring it.
  • Use the following table to determine the maximum current for whatever wire gage is being used.



   AWG Gauge  

 Max current (Amp) 





















Take the maximum current value obtained from the table and find the largest fuse you can find that still falls within the limitations. DO NOT EXCEED THE VALUES ON THIS TABLE! Common automotive blade-style fuses exist at 5A-30A


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