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Old 09-09-2019, 09:03 AM   #1
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100 amp breaker for my 135 amp windlass...

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.
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Old 09-09-2019, 09:46 AM   #2
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Your original breaker probably failed because of many trips and that is why it started tripping with low load.

Your solution sounds reasonable. You didn't say it but I assume that the new two pole breaker is rated for 200 amps per pole and you are only using one pole for the windlass.

Breakers usually protect wire and not the device so 200 is appropriate for #2 wire. Some windlasses have internal thermal breakers to protect the motor.

Your set up is a little unusual. Most windlasses have a surface mounted breaker near the main panel or in a panel near the batteries. Surface mounted breakers have a wide current range available. So if you ever need the extra positions on your panel, consider adding a surface mounted breaker nearby.

David
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Old 09-09-2019, 10:57 AM   #3
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Breakers usually protect wire and not the device so 200 is appropriate for #2 wire


David
2/0 I would say, not #2. #2 will be way over 100 deg C at 200 amps.
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Old 09-09-2019, 11:20 AM   #4
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How long is the run to and from the windlass?
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Old 09-09-2019, 11:21 AM   #5
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2/0 I would say, not #2. #2 will be way over 100 deg C at 200 amps.



The chart I have says boat wire in size 2 AWG with 105 degree C insulation is good for 210 amps at 30 degrees C.



I forgot to mention, the 2 AWG wire connected to the breaker is only about 18 inches long and goes to a terminal block. The wire that runs to the windlass from the terminal block is at least 1/0, maybe 2/0, it's huge.
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Old 09-09-2019, 11:29 AM   #6
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Have you measured the voltage at the windlass when it is under load? I would confirm that you donít have a voltage drop from wire size or corroded connections. That could cause the breaker to trip and with corrosion as it gets worse the breaker will trip more easily.
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Old 09-09-2019, 12:04 PM   #7
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The chart I have says boat wire in size 2 AWG with 105 degree C insulation is good for 210 amps at 30 degrees C.



I forgot to mention, the 2 AWG wire connected to the breaker is only about 18 inches long and goes to a terminal block. The wire that runs to the windlass from the terminal block is at least 1/0, maybe 2/0, it's huge.
I agree; for a very short run of #2 out of the engine room, you are good.
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Old 09-09-2019, 02:04 PM   #8
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Have you measured the voltage at the windlass when it is under load? I would confirm that you donít have a voltage drop from wire size or corroded connections. That could cause the breaker to trip and with corrosion as it gets worse the breaker will trip more easily.

I looked at the connections on the windlass a month ago when I was in my chain locker pulling disconnecting the chain from the boat so I could pull all the chain out to measure it. The windlass connections looked spotless. I did not measure voltage though. I will check it out, thanks for the heads up.
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