Help a friend

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fallguy1000
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Help a friend

Post by fallguy1000 »

Anyone really smart about complex DC wiring on a boat?

My wiring is getting really complex. 4 remote battery switches, a Victron inverter and a Czone combination output interface with a digital breakout box. Two Victron step up smart chargers from engines to the house, but the house can't start the engines cause of the voltages, 12v starts and 24v house...

I just have one question at the moment.

If I run a 2/0 wire to a fuse block inside or a post, can I reduce the next wire to a 2 gauge at some point and how? I am just trying to understand the fusing.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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Jaysen
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Re: Help a friend

Post by Jaysen »

Is the 2ga fused after the 2/0 or directly connected?
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

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Jaysen
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Re: Help a friend

Post by Jaysen »

To explain the question...

If your reduced line is not fused it becomes the fuse via melting. This is what is called “very bad”. If you put a fuse between the 2/0 and the 2ga that limits the amperage on the 2ga (fuse blows before wire starts a fire) you would be safe.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

fallguy1000
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Re: Help a friend

Post by fallguy1000 »

That is exactly what I thought. I need a fuse rated for the 2 ga. Thanks Jaysen!

If I want to run 2 2 gauge wires off the 2/0, is that possible?
My boat build is here -------->

viewtopic.php?f=12&t=62495

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Jaysen
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Re: Help a friend

Post by Jaysen »

If you fuse them, yes. And remember the fuse is not “the what you want to run” but to prevent the wire from melting. If the max amperage on for 2a is 100a put an 80a or 90a fuse at the reduction point. Then you fuse each branch off the 2g as needed.

Remember to use the 24v numbers for max amperage calculations and not 120. Big differences in the results.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

TomW1
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Re: Help a friend

Post by TomW1 »

Fallguy here is what I would do. Take the 2/0 to a small box that would hold a fuse for it, probably a 100 amp and for the 2ga coming out. You can look up what size of fuze you need at various vendors. I have a question for you, why are you going to the trouble of going to 24V when most of the Marine electronics operate on 12V? Don't forget you also need to run a ground back to the motor in the same conduit you pull the 2/0. A lot of guys have bought there wire from this company good prices, it is on mine and no problem for 14 years. https://www.bestboatwire.com/

If you do need 24V for some things set up a second breaker box just for them. Most of your 12V will be fused and switched at the helm, lights, fish finder, bilge pump, etc, etc.

Hope this helps a little.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

fallguy1000
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Re: Help a friend

Post by fallguy1000 »

Everything has been purchased at 24v. There ain't no changing that game. It was done to reduce wire sizes. At the moment, not sure I agree with the decision entirely, but that ship has sailed. Lotsa 24v stuff installed and purchased.

I gotta do some drawings is all.

Dan
My boat build is here -------->

viewtopic.php?f=12&t=62495

TomW1
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Re: Help a friend

Post by TomW1 »

Fallguy good luck with your drawings.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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