Circuit breaker for trolling motor?

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Markeb63

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I just purchased a transom mount Minn Kota trolling motor to push a 12 foot john boat. It's a 12-volt, 34 lb thrust model. They suggest installing a 60 amp circuit breaker on the red wire. Is this really necessary?

Thanks
 

JB

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Re: Circuir breaker for trolling motor?

Re: Circuir breaker for trolling motor?

For safety reasons it is really necessary, Markeb.

I would be more inclined to a 40 amp CB, but if Minn Kota says 60 go 60.
 

Markeb63

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Re: Circuit breaker for trolling motor?

Thanks JB. What is the circuit breaker designed to protect against? I like to understand the why's of what I'm doing but electricity is not one of my strong suits.
 

JB

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Re: Circuit breaker for trolling motor?

Should something in the troller short out you can get a fire right there by your gas tank unless a circuit breaker or fuse prevents the high current/high heat situation.
 

Silvertip

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Re: Circuit breaker for trolling motor?

A circuit breaker does the same thing that a fuse or circuit breaker does in your house or car -- it protects against overload and short circuits. Stick something metal into both holes in a wall outlet and you may get a brief spark but the fuse or breaker will pop thus preventing that outlet from becoming an arc welder. It also eliminates a potential 911 call to summon the fire and rescue services which would likely get your name in the paper the next day for conducting a stupid "I wonder why" experiment. You don't need a 60 amp but a 50 would be fine. The size breaker used depends on two basic things. 1) the maximum current (amps) the 34# troller will draw (roughly 40 amps) and 2) the size (gauge) of the wire running from the battery to the motor. Using a 60A breaker means the wire must also be capable of handling 60A. If not, the wire becomes the fuse as it will overheat, melt the insulation and potentially cause a fire and the breaker would never open.
 

Dodger1234

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Re: Circuit breaker for trolling motor?

I have a 55/lb thrust Minn Kota and it had no fuse / breaker system on my boat. After seeing a post on here about how important it was to have I called Minn Kota. They said I should install a 60 amp fuse. I asked them that if it was so important for safety reasons why would they sell there product with out a $10.00 fuse system. The line went quiet and he was uncertain as to why, end of story.
My $0.02 worth.
Dodger1234.
 

Silvertip

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Re: Circuit breaker for trolling motor?

Think about it. Every item you plug something into an outlet in your house that device likely has no fuse. That's what the fuse/breaker panel is for in your house. The guy on the other end of the line is obviously not an electrical genius or he would have explained that the fuse/breaker is installed "ahead" of the device not "as part of it". The breaker interrupts current flow to the wires leading to the motor so a problem anywhere along the way would cause it to open thus preventing further damage and the potential for fire. If everything is working just fine you don't need a fuse or breaker. It is when things go wrong that it comes into play. You don't need to wear a cup when playing sports either but if you ever get hit there, you'd wish you had one on. Make sense?
 

Texasmark

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Re: Circuit breaker for trolling motor?

You can go to auto parts stores and buy a fuse (box of fuses) and fuse holder for less than $10....My 65 lb Motorguide TM is designed for, and has, a 40 ampere fuse and it is in the line (actually two in two lines as it is a 24v TM) right at the battery. While there get some suitable terminal lugs and lug it right into your TM wire at the battery.

Mark
 

Dodger1234

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Re: Circuit breaker for trolling motor?

Think about it. Every item you plug something into an outlet in your house that device likely has no fuse. That's what the fuse/breaker panel is for in your house. The guy on the other end of the line is obviously not an electrical genius or he would have explained that the fuse/breaker is installed "ahead" of the device not "as part of it". The breaker interrupts current flow to the wires leading to the motor so a problem anywhere along the way would cause it to open thus preventing further damage and the potential for fire. If everything is working just fine you don't need a fuse or breaker. It is when things go wrong that it comes into play. You don't need to wear a cup when playing sports either but if you ever get hit there, you'd wish you had one on. Make sense?


Then why would all of the other electronics on my boat have a fuse on them from the manufacturers but only the Minn Kota did not?

Dodger.
 

gt

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Re: Circuit breaker for trolling motor?

1 thing that SilverTip mentioned, and I'd like to stress. Make sure the size of the fuse/circuit breaker is at or below the rating of ALL the wire in that circuit.

I think the ratings are: note - I said I THINK!. hopefully, someone will step in and verify.
60 amp = #6 wire
50 amp = #8 wire
40 amp = #10 wire
wire size can be bigger than needed, but fuse/circuit breaker can't be bigger than wire rating (hope that makes sense), while at the same time, being the correct size as to handle the trolling motor draw, but close enough to pop if needed to protect the motor.

Quick story. I recently worked on a friends boat. Trolling motor didn't work. #8 wire/40 amp fuse (that is ok), BUT fuse holder was only rated for 20 amp fuse, with short #12 leads spliced into the #8 wires in the boat. Fuse holder and wires were melted/burnt. Luckily, didn't start a fire, but easily could have.

Gary
 

Silvertip

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Re: Circuit breaker for trolling motor?

Because MinnKota has no idea where in your boat the battery(ies) for the troller will be mounted. If you have an 18 foot boat with the troller up front and the batteries at the rear you have a 36 foot run of wire. That alone makes a difference where the circuit breaker would be installed. Some trollers are not even equpped with terminals on the end of the wires since they have no idea how the purchaser will wire the rig. Your accessories are fed from the fuse panel at the console. The console is fed by the boat harness which IS protected by a circuit breaker or fuse at the battery POS post. That breaker or fuse (20 or 30 amp) opens if there is an issue in the feed to the fuse or breaker panel but is far too large for the accessory since the wire would burn up before the fuse blew. Accessories typically draw five amps or less and can have a much smaller fuse and fuse holder than your troller. Besides, the fuse for that device is not even needed since there is generally an empty fuse slot in the panel. If not, then you need it. Head to your library and check out a book that describes low voltage wiring. You will quickly learn why, where, and when fuses and breakers are required, and the effect of distance and wire size on current carrying capability.
 

Dodger1234

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Re: Circuit breaker for trolling motor?

Thanks Silvertip, my mindset is around my 16' tiller fishing boat with the bow mount Minn Kota. The wires basicaly drop straight down to the battery and when I purchased the boat there was no fuse between the battery and trolling motor.
Dodger1234.
 

Silvertip

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Re: Circuit breaker for trolling motor?

Drop any wrench across the battery terminals sometime and then come back to tell us if you need a fuse or breaker or not -- regardless where the wires run from/to. 12 volt batteries make excellent arc welders and can melt virtually any gauge wire if shorted. Like any electrical circuit, if a short never occurs you don't need protection. If it does and you don't have that protection, you will likely want to be out of the boat. You seem to be trying to reason your way out of installing this protective device. We could care less if you add it or not and the motor will operate just fine without it. But you should think about the safety of your passengers. They don't know what you have or have not done.
 

jeff_j

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Yes, dragging up an old thread, but this is the same situation I am in, except I am one step further into it. I have a 14' Valco aluminum boat with an outboard and a transom mounted trolling motor.

I have a battery mounted near the bow (for weight distribution) and have run 6 gauge wiring to that back of the boat where it is connected to the trolling motor wiring. The battery is in a Minn Kota Power Center battery box that has a 60 amp breaker built into it. I took the trolling motor off of the transom to get it out of the way while I was working on the outboard.

I went to put the trolling motor back onto the transom to go boating and tried to turn it on and it didn't work. I noticed that the handle was about halfway between OFF and 1 (forward). Probably got nudged there when I set onto the floor of the boat.

I opened up the trolling motor to look around and it wasn't pretty. Two of the wires from the controller heading down into the mast had obviously got hot and melted insulation. I removed the prop and got into the lower unit and the armature was black, the brushes were stuck in their mount, and several wires had the insulation burnt completely off of them. There was a black gooey tar like substance present and the small was definitely of something that was burnt.

SO, while the 60 amp circuit breaker absolutely protected the 6 gauge wiring from the battery back to the trolling motor, and the wiring going into the trolling motor (maybe 10 gauge?), it did nothing to protect the wiring in the trolling motor itself (which is smaller that the wiring from the battery and the trolling motor external wiring). Going forward (and considering the information in the preceding posts), I am wondering if I could install an additional fuse to protect the trolling motor wiring somewhere in or near the trolling motor to protect it should I find another way to put it in jeopardy?

What size (30 lb thrust motor) fuse?

And where should it be located?
 
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