Wiring Question

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PopPop
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Wiring Question

Post by PopPop »

I am restoring a 1988 21' Starcraft Mariner CC with 90 hp Evinrude. My question is what gauge marine wire should I use for the rewiring. I was thinking 14 Guage, but wasn't sure. I know the main battery wires are a lot bigger.
Thanks for Your Help!

fallguy1000
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Re: Wiring Question

Post by fallguy1000 »

PopPop wrote: Mon May 30, 2022 6:23 am I am restoring a 1988 21' Starcraft Mariner CC with 90 hp Evinrude. My question is what gauge marine wire should I use for the rewiring. I was thinking 14 Guage, but wasn't sure. I know the main battery wires are a lot bigger.
Thanks for Your Help!
16 gauge is the minimum allowed for any boat wiring other than devices with pigtails less than 16 gauge

However, the current carrying capacity of 16 gauge wire is very low. So you need to evaluate each circuit and determine the current flow.

For the most part wires in a boat that carry more current..

Toilet macerators
Washdown pumps
Air horns
Battery
Generator
Solar
Onboard chargers
Trollbridge chargers
Trolling motors
Fuse blocks supporting multiple items.

You can find ampacity charts online.

All wire circuits in a boat must be fused within 7" of the source of power, except for the starting circuits. MRBF fuses are handy for this to get fused power to a block. Lugs are limited to four terminals per abyc rules. My skiff violated this rule, my larger boat does not.

Also, glad to help with more specific questions. I know quite a bit about wiring. A couple bits of uncertainty remain on my build that I am ironing out with an engineer friend.

All grounds need to be connected. I am not a fan of using the vessel for a ground and will skip the reasons why.
My boat build is here -------->

viewtopic.php?f=12&t=62495

TomW1
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Re: Wiring Question

Post by TomW1 »

fallguy is correct each item must be fused depending on its draw. If you have a trolling motor, it is usually fused near it do to the long runs of the wires.

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: Wiring Question

Post by fallguy1000 »

TomW1 wrote: Mon May 30, 2022 5:27 pm fallguy is correct each item must be fused depending on its draw. If you have a trolling motor, it is usually fused near it do to the long runs of the wires.

Tom
ABYC requires fusing or breakers within 7" of the power source.

Here is a good link to read. 7" is not always attainable, but the reason fuses are kept close is to prevent wires from getting hot before the fuse blows..

Sorry to argue, but many practices are not necessarily meeting rules.

Make a list of all the things that use power and what voltage.
My boat build is here -------->

viewtopic.php?f=12&t=62495

TomW1
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Re: Wiring Question

Post by TomW1 »

fallguy you have misunderstood the ABYC rules or I am misunderstanding you. The power from the battery can be run to a fuse block with a heavier main wire. The wires to the accessories from the fuses must then depend on the amperage draw of that accessory. Something like this ABYC approved Blue Sea fuse box https://www.fredwarner.net/product/blue ... Ad%20group

I am not sure where you got the 7" from the power source but that is not right. It depends on the wire guage and fuse size based on the amperage of the accessory. The main wire is also fused within 7" of the battery to protect the battery.

Regards, 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: Wiring Question

Post by fallguy1000 »

TomW1 wrote: Tue May 31, 2022 12:06 pm fallguy you have misunderstood the ABYC rules or I am misunderstanding you. The power from the battery can be run to a fuse block with a heavier main wire. The wires to the accessories from the fuses must then depend on the amperage draw of that accessory. Something like this ABYC approved Blue Sea fuse box https://www.fredwarner.net/product/blue ... Ad%20group

I am not sure where you got the 7" from the power source but that is not right. It depends on the wire guage and fuse size based on the amperage of the accessory. The main wire is also fused within 7" of the battery to protect the battery.

Regards, Tom
Simple. Cannot run a wire from the battery say 20 feet to a breaker at the front of the boat by the trolling motor; won't meet the rules.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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