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#572769 - 09/09/19 10:00 AM 100 amp breaker for 135 amp windlass...  
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Dave R Offline
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Dave R  Offline
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Raymond NH
I'm very impressed with my Tollycraft so far, but I discovered a really strange lapse in engineering quality that really surprised me last weekend.

My windlass has always easily tripped its breaker if loaded down for more than a couple of seconds. It was easy to live with since the boat was more than capable of breaking the anchor free, but it was something I intended to address in the off season. Well, the boat forced me to address it much earlier than planned as the breaker started tripping with no load at all when we were attempting to retrieve than anchor. Fortunately, I was anchored in really shallow water and we were able to get the (60 lb) anchor aboard manually without a lot of effort.

Anyway, I dug into the breaker panel, pulled out the offending breaker, and learned that it was rated for 100 amps (these breakers don't have a capacity label on the front). That seemed a little low so I looked up the specs on the windlass which stated that the normal working current is 110 to 135 amps. The specs also called for only 6 AWG wire in my application (which seems kinda small at 120 amps in rating). Interestingly, Tollycraft used 2 AWG wire (good for 210 amps) but why they only used a 100 amp breaker is beyond me. That said, the boat is 27 years old and the breaker is original, so I guess it worked for a long time....

When I was shopping for a new breaker, I discovered that the maximum current possible in a single pole breaker of this physical size (Blue Sea C-series) was 100 amps. The only way to increase the current over 100 amps is to go with a double pole set of 2 ganged breakers that take up two slots in the panel. This is where it gets interesting, the panel had an extra breaker in it that was unused, so doubling the size of the windlass breaker was easy. With the 210 amp wire and the extra breaker slot, It's almost as though Tollycraft had planned on a 200 amp breaker all along and there was a mistake in the build.

I got a 200 amp breaker by mail on Friday and had it installed and working on Friday evening. The new one has a label on the front stating that it's 200 amps, which is nice. This is the second breaker failure on the boat since May. I will be getting a few spares over the Winter.

Last edited by Dave R; 09/09/19 10:02 AM.

"Mischief Managed II"
1992 Tollycraft 44 Cockpit Motor Yacht
Twin CAT 3208TA inboards
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#572770 - 09/09/19 12:43 PM Re: 100 amp breaker for 135 amp windlass... [Re: Dave R]  
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captkevin Offline
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So how do you go from 100 amp single pole to a 200 amp double pole breaker? Do you have to run another wire to the windless? Is it running 220 volt then?


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#572771 - 09/09/19 03:23 PM Re: 100 amp breaker for 135 amp windlass... [Re: captkevin]  
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Dave R Offline
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Dave R  Offline
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Originally Posted by captkevin
So how do you go from 100 amp single pole to a 200 amp double pole breaker? Do you have to run another wire to the windless? Is it running 220 volt then?


The windlass runs on 12 volts DC.

Its basically two breakers in parallel that provide a 100 amp path on each leg and if one trips, the other does as well. The two inputs are tied together with a bus bar and the two outputs are tied together with another bus bar, so from a load point of view, it's all one big breaker. They make them with up to three in a stack to get 300 amps.




[Linked Image]

Last edited by Dave R; 09/09/19 03:30 PM.

"Mischief Managed II"
1992 Tollycraft 44 Cockpit Motor Yacht
Twin CAT 3208TA inboards
#572772 - 09/09/19 05:19 PM Re: 100 amp breaker for 135 amp windlass... [Re: Dave R]  
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captkevin Offline
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Thanks for the information - have never dealt with 12v power that much amps.


2004 Rinker 232
2010 Dodge Ram Crew Cab Laramie 4x4
#572774 - 09/09/19 08:16 PM Re: 100 amp breaker for 135 amp windlass... [Re: captkevin]  
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Dave R Offline
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Dave R  Offline
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Raymond NH
Originally Posted by captkevin
Thanks for the information - have never dealt with 12v power that much amps.



Same here. My inverter draws 300 amps. Massive wires...


"Mischief Managed II"
1992 Tollycraft 44 Cockpit Motor Yacht
Twin CAT 3208TA inboards
#572781 - 09/12/19 05:10 PM Re: 100 amp breaker for 135 amp windlass... [Re: Dave R]  
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WayWeGo Offline
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Interesting. I guess the internal resistance of the dual breaker channels is close enough to split the current fairly accurately.

I was going to suggest that a previous owner might have swapped out the breaker to a smaller value, but since Blue Seas doesn't make one, that doesn't make sense. Unless, of course, there was a 200A dual breaker there previously and it was replaced with a 100A one for some reason.



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#572785 - 09/13/19 02:50 PM Re: 100 amp breaker for 135 amp windlass... [Re: WayWeGo]  
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Dave R Offline
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Dave R  Offline
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Raymond NH
Originally Posted by WayWeGo
Interesting. I guess the internal resistance of the dual breaker channels is close enough to split the current fairly accurately.

I was going to suggest that a previous owner might have swapped out the breaker to a smaller value, but since Blue Seas doesn't make one, that doesn't make sense. Unless, of course, there was a 200A dual breaker there previously and it was replaced with a 100A one for some reason.


The way the panel was built and engraved, there is only one slot for the windlass breaker. The slot above it is used for the main DC distribution breaker, and the slot just below it is for the Fireboy system. There was an unused breaker below the Fireboy breaker in the bottom slot that with no label. I removed the windlass breaker moved the Fireboy breaker up one slot, removed the unused breaker, and filled the two empty slots with the new double breaker for the windlass. I was really glad there was space for the double breaker...

Before:

DC Distribution
Windlass
Fireboy
Unused Breaker

After:

DC Distribution
Fireboy
Windlass
Windlass

There's a third mini bus bar electrically connecting the double breakers together in addition to the bus bars on in the input and output. Guessiing it's there to ensure that one when side trips, the other is forced to do the same.


"Mischief Managed II"
1992 Tollycraft 44 Cockpit Motor Yacht
Twin CAT 3208TA inboards

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