How to choose the correct RV fuse

2020-08-11

Before we start guessing which fuse that we should use. It is important to know Voltage, Current and Power. These three item will always show up in your RV electrical circuits. Only when making clear of how they work you can never meet the potential problem. 

>>Understand Battery Wiring

Firstly double confirm the voltage of your battery system in your camper. Generally there come 12V and 24V voltage. If you buy a pre-owned vehicle and have no idea of the house battery voltage, please follow this diagram to check the wiring and you can easily tell then answer. 

>>What is the appliance power?

Appliance will draw the power from the house battery. Check the specification label of the loads. You will find XXX WATTS, that is the parameter of the power. You will easily find it on the backside of the load like this 120VAC/12VDC freezer fridge. 

>>Start calculating!

Now let's measure the current draw of the circuit. Generally 12V DC load accepts a voltage range at 10.5~16.0V(×2 for 24VDC) for good working. Here is the formula for calculating correct Amp;

Max. DC load power(Watt) / 10.5VDC * 125% = Reasonable current for fuse(Amp)
* Some DC load will also work even battery is lower than 10.5VDC. For protecting battery ensure battery voltage is always higher than 11.0V.

* 125% is a good factor for allowing the DC load start work with its surge power, like the 12V compressors. But please understand 125% is not a definite correct parameter. Please consider increase or decrease this factor. 

For Example, the 12VDC freezer fridge;
Wire the 12VDC, its rated power is 175 watts, but it also has a surge power when internal compressor working(inductive load). 

175 watt / 10.5VDC *125% = 29.8Amp
Therefore choose the 30Amp fuse. 

>>Optimize the electrical circuit

You may already have the the single fuse and fuse holder to protect each specific circuit. But if you have multi circuit DC loads and the mass wiring without management will cost a lot of time to find out the fault circuit by the voltage meter. Let's get optimize it!

Popsail provide the 12-circuit fuse hold set. It can be used as the DC distribution panel to protect your DC loads working, like LED lights, RV vent fan, 12V(or 24V) freezer, 12V(or 24V) water pump, etc. 

Click the picture to check view morethis easy use mutliple fuse holder box.comprehensive interface with fault LED indicator. As soon as the fuse is burnt or the DC cable wiring get loose or break, LED on the specific circit will ON and you can easily find "who is the bad boy". (See in below)

>>Never forget use the correct guage cable

After installation of the fuse holder box, please select the high quality power cable as following chart;

You may also need the tools to fasten the screw and the nuts;

Click the picture to view the ratchet wrench and ratchet screwdriver kit

ELECTRICAL HARZAD MAY HAPPEN!!  KEEP SAFE!! keep sharp, keep safe and use correct tool for installation.