If you just bought your trolling motor and want to wire it properly, do not forget to install a circuit breaker or a fuse. It doesn’t cost much and will protect your investment.
Today we’ll explain why circuit breakers are important, what are different types of breakers and fuses, and how to wire them on your boat.
Let’s get started.
What Is a Circuit Breaker?
A circuit breaker is an automatic electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit.
Circuit breakers are available in different sizes, depending on the amperage they are rated for. For example, a trolling motor may require a 20-amp, 30-amp, or 50-amp circuit breaker.
What Is a Fuse?
A fuse is a thin piece of metal that melts when too much current flows through it. This interrupts the flow of electricity and protects the circuit from damage.
Fuses work very fast and stop the flow of electricity almost instantly.
This speed is usually good, as it protects your motor and electronics. However, some systems experience short-lasting current surges, and even correctly matched fuses could be oversensitive and melt when it’s not needed.
Fuses are available in different sizes, just like circuit breakers. The size of fuse you need will depend on the amperage rating of your trolling motor.
Circuit Breaker or Fuse?
So, which one should you use to protect your trolling motor circuit – a circuit breaker or a fuse?
Both have their advantages and disadvantages.
Circuit breakers can be reset after they trip, while fuses must be replaced. This makes circuit breakers more convenient to use. However, they are also more expensive than fuses.
Since fuses are destroyed by heat, they can’t be reused like circuit breakers and must be replaced. So if you decide to install a fuse instead of a circuit breaker on your boat, make sure you carry spares and know how to install them.
Fortunately, they are inexpensive.
Why Your Trolling Motor Needs a Circuit Breaker
A circuit breaker works by “tripping” the circuit whenever there is too much current flowing towards the motor.
This overload happens when your prop gets stuck in weeds, rocks, etc., and can’t rotate freely. The motor will then start to draw more current to increase power. This excess current can cause overheating and damage to your trolling motor.
An overload could also happen when your wiring is inadequate, for instance, when the wire is too long and the wire gauge too small for the current it is supposed to carry.
Another function of a circuit breaker is to cut off the electricity supply if there is a short circuit in the system. For example, a wire or wire connection could be exposed or damaged. This could lead to sparks and even fire.
Fortunately, a properly sized and wired circuit breaker can prevent this.
Once the cause of overload or a short circuit has been removed, the flow of electricity can be reset manually. All you need to do is to use the switch on the breaker to reconnect the circuit.
How to Choose a Trolling Motor Circuit Breaker?
There are two main things to look for when selecting a circuit breaker for your motor: Current rating and voltage range (dc).
When choosing a circuit breaker or fuse for your trolling motor, it is important to choose one that is properly sized. If the circuit breaker or fuse is too small, it will trip too easily. If it is too big, it won’t trip at all and your trolling motor could be damaged.
To find the right size, you need to know the amperage rating of your trolling motor. This information can be found in the owner’s manual or on the manufacturer’s website. Once you know the amperage, choose a circuit breaker or fuse with the same or higher rating.
For example, if your trolling motor is rated for 20 amps, you would need a 20-amp circuit breaker or fuse.
It is expressed in Amps (A), for example, 50 Amp or 60 Amp. The Amp rating of a circuit breaker should be slightly above the maximum amp draw of your trolling motor. For instance, if your motor draws a maximum of 55 Amps, you should pick a 60 Amp circuit breaker for your wiring.
DC Voltage Range
The next thing to check is that a circuit breaker works with the voltage of your motor. Many circuit breakers are designed to work in the range of 12V to 48V, which covers basically all trolling motors in the market. Just make sure your motor fits within this range, and it is rated for direct current (DC).
A good circuit breaker is:
- Waterproof, to prevent corrosion.
- Ignition-protected, to prevent electrical fires.
- Reset manually, so you don’t have to replace it after each trip.
How to Wire a Circuit Breaker or Fuse
A circuit breaker or a fuse should be installed on the positive (+) wire between your battery and the motor. The closer to the battery, the better.
Installing a circuit breaker is easy as long as you are comfortable working with wires and connections.
You can hire a marine technician to install a circuit breaker for your trolling motor. However, if you are looking to do the job yourself, then here’s a set of instructions you can follow:
Step 1: Find a Good Location
Circuit breakers should be as close to the battery as possible to prevent excessive voltage drop. A good rule of thumb is to keep the length of the wire between the battery and circuit breaker under 2 feet.
Step 2: Mount the Circuit Breaker
Most breakers come with two holes so that you can use screws or bolts for mounting. Choose a dry, flat surface to mount your circuit breaker. Pre-drill the holes if necessary.
Step 3: Connect the Trolling Motor
There are two terminals on your circuit breaker: “AUX” intended for the motor and “BAT” for the battery.
Take the positive wire (+) of your trolling motor and connect it to the terminal marked “AUX” on the circuit breaker.
Step 4: Hook up the Battery
Before you proceed, make sure to check that the trolling motor is switched off or its speed set to “0” or neutral. The last thing you want is for your propeller to start rotating unexpectedly.
In the last step, make the wire connection between the terminal marked “BAT” on the circuit breaker and the positive post (+) of your battery.
That’s it! You’re ready to go.
Circuit breakers are an important safety feature in any trolling motor system.
Choosing the right size and type of circuit breaker is essential to ensuring that your trolling motor is protected.
Have a look at our FAQ section below, and if you have any other questions – do let us know!
Frequently Asked Questions
Are circuit breakers just an optional safety feature?
If you use your trolling motor in the United States, you must have either a circuit breaker or a fuse. The U.S. Coast Guard requires them for any ungrounded current-carrying conductor.
Do you need a different circuit breaker for different brands of trolling motors?
Not at all. As long as your circuit breaker is matched to the maximum Amp rating of your motor, it will work just fine.
My battery box comes with a circuit breaker. Do I need to install another one?
No. Just make sure it has the correct Amp rating and voltage range to be safely used with your motor.
How to reset a Minn Kota circuit breaker?
To reset a Minn Kota circuit breaker, or most other circuit breakers, simply press the red button in the center of the breaker.
How do you test a circuit breaker?
The easiest way is with a multimeter. You need to set it to resistance (Ohms) first. Connect one lead to the clip terminal and the other to the screw terminal. When you turn on the breaker, it should have a resistance reading and no rating when the breaker is off.
You can also use your multimeter’s continuity setting. If there is continuity, then the circuit breaker is good. If not, then it is bad and needs to be replaced.
What are the symptoms of a bad circuit breaker?
The most common symptoms include:
- Frequent tripping
- Bad/burning smell
- Excessive heat
- “Reset” mode not working
If you suspect your circuit breaker is going bad, it’s best to replace it as soon as possible.
What size circuit breaker for a 12v trolling motor?
The size of the circuit breaker will depend not on the voltage, but on the amperage of your trolling motor. For example, if you have a 30-amp trolling motor, you’ll need a 30-amp circuit breaker.
Does the brand of a circuit breaker matter?
No, the brand does not matter as long as it is rated for the correct amperage and voltage.