Blown 30 Amp Fuse: Why Does My 30 Amp Fuse Keep Blowing?

It's not because they are angry. Blowing as fuse in slang means a person is very upset at what you or someone else has done. When it comes to electricity, blowing a fuse means the fuse box is upset at what the wiring has done and cuts off the electricity.

Why does my 30 amp fuse keep blowing? The most common reason why your 30 amp fuses keep blowing is that there may be a short somewhere. Sometimes it is the converter that goes bad, or the battery is low on power, but most often, it is a short in the wiring somewhere. This issue may take time to track down and fix.

To learn more about why your 30 amp fuses are blowing, continue to read our article. It has the information you need to know about so you can get to the source quickly. Take a few minutes and see what causes your fuses to blow.

How Can You Tell if a 30 Amp Fuse is Blown?


The first indication that your fuse is blown will be that you have no power to certain features in your RV. But that lack of power does not necessarily mean the fuse is blown. You will have to test the fuse to see if it is the source of your problem.

Many fuses have a glass body which allows you to see if the element is broken. However, the majority of fuses do not come with that glass body, and you cannot see if the fuse has blown or not.

The best way to tell if a fuse is blown is to use a multimeter. If you are not familiar with a multimeter or how it works, you have to measure the resistance of the fuse. This resistance is measured in ohms, and that is the section you want to turn your dial to before you turn on your multimeter.

The black lead needs to be connected to the COM or common socket while the red lead is placed into the ohms socket. If you are not sure which one that is VΩmA underneath it.

Once you are connected, make sure to turn the meter on, and sometimes that just means moving the dial to the 200 ohms option. Then place the fuse on a non-conductive surface and touch the leads to both ends. There is no polarity to worry about here, so it does not matter which ends you place the leads. Just make sure one is on each end.

Also, make sure the fuse ends and the lead ends are clean, so you get an accurate reading. You do not have to pull the fuse to test it, but if you leave it in place, make sure the power is turned off.

There should be a change in the reading if the fuse is good. If the reading says 1 or 100%, then the fuse is bad. You will need to replace it.

What Does a Blown 30 Amp Fuse Look Like?

Sometimes it is hard to tell what a blown fuse looks like. The reason for this is because the elements may be too small to see accurately. Also, some fuses are not transparent, which means mere looking will not help you make the proper diagnosis.

On certain glass fuses, you can see a burn mark as well as the broken element. These are usually on the older traditional style of fuses. The newer ones may be color-coded, but they may also be very small.

Inside the more modern styles, the elements may be hard to see. But if you see an unbroken line between two points, then the fuse is good. If you see a little break in that thin line, then the fuse is bad.

You might see some burn marks as well. Not every time, but sometimes that burn mark will appear, letting you know very clearly that the fuse is not usable anymore.

With that said, there are those fuses that are not transparent, and they do not look bad at all. That is when you have to pull out your multimeter and do a little testing.

Why Does My 30 Amp Fuse Keep Blowing?


There are many reasons why a fuse will blow. If the fuse continues to blow after being replaced by new ones, then you know you have a severe problem on your hands. Or you simply have a polarity issue.

The polarity issue simply means that the battery wires got crossed somehow, and that is understandable as sometimes battery cable colors are not always clear. Then there could be a problem with the battery.

Either it is not fully charged, incapable of charging, or there is a bad cell. If you suspect the last one, then you have to check each cell individually. A hydrometer is needed, and you need to check the gravity of each cell.

Another source for this problem will be a short in the 12-volt system. This may take some time to find, and you would have to have the right multimeter to discover the location.

Then, the problem source may be with the converter. If it is too powerful, it is pushing too much electricity to the battery and blowing the fuse. The charging module in the converter may be bad, or the converter itself is becoming faulty.

There are many other sources for this problem, and one solution would be to take out all 12-volt fuses, then place a good one in the battery spot. If the fuse remains good, start replacing all the fuses one by one.

This will help you see where the problem may lie if one of the replacements blows when inserted correctly into its spot.

RV Converter Blowing 30 Amp Fuse

This is a common problem that can arise when there is an issue with the converter. If the battery fuse blows right away, then you have a problem with the converter. When a converter starts to fail, it creates what is called a dead short.

It is not the only source for a dead short, but it is a place to start looking. When you are missing all your DC power, then that lack of power is pointing you to a problem in the converter.

Your solution here will be either to have the converter repaired or to go out and buy a new one. But make sure the converter is going bad before you go out and buy a replacement. You do not want to spend money you didn’t need to for a part that is not needed.

Keep in mind that while the converter may be the source, sometimes the battery tries to shift the blame. When you have problems with DC power, it may be that the batter has a fault or has gone bad on you. It just makes the converter look bad.

However, when the converter is built into the fuse panel and the fuse blows quickly, it is a sign of a dead short, and you have to track it down.

30 Amp RV AC / DC Fuse Panel


This little device is basically your power grid control center. It receives the power through the extension cord you have plugged into the shore power system. That means that 120 volts of power are coming into the fuse box.

The AC-powered appliances and features are protected by residential-style circuit breakers. You know how to handle those if they trip. Just shut them off and turn them back on again.

This is not possible with the DC side of the panel. The DC-powered features, etc., are protected by automotive-style fuses, and once they go bad, you have to replace them. There is no re-setting involved here.

Even if you see a burnt fuse, you should test it first just to make sure it has gone bad. A 12-volt meter will help you test it out. Now some newer RV models have little lights underneath different fuses.

If those little lights glow, then the fuse is bad. It is a way to simplify your search for a bad fuse. Make sure to use the right safety measures when working with the distribution panel. Turn the power off to the panel except when testing the fuses.

Each fuse should register 12 volts of power if they are in fine working order. If you are afraid of working with electricity, then get a pro to help you.

30 Amp Fuse for RV Battery

When you have power to most of your appliances and features, you may still see a 30 amp fuse blow. You can narrow your options by checking to see if the lift jacks work or not. If they are tied directly to the battery and do not work, then the 30 amp battery fuse has blown.

If the battery is dead and you can charge it with a portable charger and use the lift jacks, yet the fuse still blows, there may be a problem with the battery. It is dead and needs more than 30 amps to recharge.

But that may not be the only problem. Sometimes this situation can occur when you lower the tongue and forget to clear the wires and get them out of the way. That lowering can squeeze the wires and cut the insulation so that the wire shorts out the battery.

The wire that gets squeezed may be connected to the break-a-way system from the converter. Once you replace the wire, the system and the battery should work fine again.

How to Use An Analogue Meter


In today’s digital world, many people forget that analogue systems and tools still exist. They prefer to use the meters with digital readouts because they are easier to understand.

Analogue meters are old school and have been around forever. They may be overshadowed by their digital counterparts, but they still provide accurate readings. The biggest difference between the analogue and the digital meters is the display.

The hookups are the same, and the process of testing is the same. It is just that with an analogue multimeter, you have to watch the needle go over a fixed scale. When you touch the leads together, the needle will go to the spot that shows there is no resistance.

Then you touch the leads, one to each end, to the fuse, and if you get the same result, the fuse is good. If you don’t, then the fuse is bad. Make sure, like the digital multimeters, that the fuse is on a non-conductive surface and all ends and leads are clean.

Where to Buy RV 30-Amp Fuses

If you have had trouble with your car’s fuses, then you should already know where you can get replacements for your RV. The fuses used in an RV are the same as those used in a regular car or truck.

But if you are stuck and never had to work on a fuse before, you can try any of the RV parts and accessories stores like Camping World to find a new one. You may want to pick up a few to have on hand when the blown fuse situation arises again.

Or, if you want to save money, as RV parts stores can get a little expensive, try Home Depot, Lowes, and Amazon. They always carry a good supply of fuses for every need.

Some Final Words

When 30 amp fuses blow, it is not the end of the world. All you have to do is hunt down the source for the blown fuse and repair it. These sources are varied and can be located in difficult-to-reach spots.

As we said earlier, if you do not like working with electricity, let the pros handle the search and repair.

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