Questions about fuses and trolling motors... why? where?

[CodyPomeroy]

I was wondering: #1. What is the reason for a fuse on the trolling motor? #2. Where is the best place to place it? Some say close to motor, others say close to the battery. Does the type of fuse matter? #3. In the pic below, from the manual for my BPS prowler 50/36 motor, it appears only the model with clips requires a fuse. Do I even need a fuse? #4. Thanks.

 

[Bob Landry]

I was wondering: #1. What is the reason for a fuse on the trolling motor?

The purpose of the fuse is to protect the wire, not the trolling motor.

#2. Where is the best place to place it? Some say close to motor, others say close to the battery. Does the type of fuse matter?

It should be within 7" of the battery. While a fuse will work, a resettable circuit breaker is prefered.

#3. In the pic below, from the manual for my BPS prowler 50/36 motor, it appears only the model with clips requires a fuse. Do I even need a fuse? #4. Thanks.

Any wire coming off the positive terminal of a battery should be protected.

 

[CodyPomeroy]

I was wondering: #1. What is the reason for a fuse on the trolling motor?

The purpose of the fuse is to protect the wire, not the trolling motor.

#2. Where is the best place to place it? Some say close to motor, others say close to the battery. Does the type of fuse matter?

It should be within 7" of the battery. While a fuse will work, a resettable circuit breaker is prefered.

#3. In the pic below, from the manual for my BPS prowler 50/36 motor, it appears only the model with clips requires a fuse. Do I even need a fuse? #4. Thanks.

Any wire coming off the positive terminal of a battery should be protected.

Not to be a wise-a** but can you tell me why that is?

 

[parkerdog]

Not an electrician here but you put the fuse close to the battery in case your wire gets damaged somewhere and creates a short.
Or if the motor malfunctions and draws too many amps a fuse will break the connection and keep the wire from melting, causing a fire etc..

 

[TNtroller]

fire be very bad on boat. no place to hide from fire.

 

[Bob Landry]

If you are asking why that is, the answer is very simple. The purpose of a fuse or circuit breaker is to protect the wire, not the device. if you have a motor short, for example a trolling motor, there's no way to protect it, it has already failed. What you don't want it to do is draw enough current to melt insulation and short a bare wire to a frame or hull, remember the TM is already dead, you can't save it. You also want to protect as much of the wire as you can, thus the reason for putting the fuse as close to the battery as possible. ABYC, which is an organization that sets design parameters and requirements for marine systems says to do it thay way, so I comply. Every other marine electrician that I know adheres to the same standards. It helps to keep us out of court.

 

[nlester]

I did not have a circuit breaker for my old trolling motor. I was in rush to get home and did not disconnect my trolling motor from the battery. The motor got turned on by accident and the propeller jamed against the boat. By the time I found the problem, all of the wiring to my trolling motor had melted and I had to buy a new motor.

I would recommend a manually resetable circuit breaker over a fuse. You want to manually reset it because you don't want the motor to start running unepectedly if the breaker resets. You don't want a fuse unless you want to carry a bag full of fuses with you on the lake. Even an normally operating trolling motor can occasionally blow a fuse. The internet is the best source for the circuit breakers.

In Texas, a manually resetable circuit breaker is the law for permeant installations.

I would connect it to the battery.