TOPIC: Electrical wiring ?

Rewiring my 1968 Corson and have a question. I want to run my pos/neg wiring from the battery (12V)located in the stern to a fuse panel forward about 14ft (6 circuit, 100amp). What guage should I use for the wiring?

First you must calculate the load, in amps, which this wire will be carrying. You would not want to carry starter current that distance. Just add up the amperage of all the items on the circuit. Then refer to any wiring handbook or look up an "Ampacity" table on the internet. This will tell you the minimum wire size for the load.

There's a chart on the link below (page 3, about 3/4 of the way dwon), looks like 100 amp for 14' would require 2 ga., but check it out;
www.arcomarine.com/xhtml/Tech%20Wiring,Voltage,Sizes.pdf

Thanks guys

...and use marine grade wiring. It is made for wet environments. It's tinned which resists corrosion, and also carries a higher load than the same automotive wire gauges.

If your just setting this up for lights and maybe radio and even lighter you should not need any bigger then 8 gage and that is heavy wire. That starter it self should run right from the battrie.
Mike aka pathfinderz1

The starter will run directly from the battery, The fuse panel will
power nav/run lights, cd, fish/depth finder, lighted speed and compass guages and an accessory circuit. Would 8 guage marine be oK?

100 Ampers on a 14 ft boat?????

What are you doing - putting the battery in the bow?

If it will just run the ignition, horn, navigation lights, radio, etc - then a 30 amp panel will be more than adequate. #8 wire will be more than adequate for the list of electrical items here. Personally, I have #10 in my boat & it's fine. Marine wire has finer strands of copper, which makes it more flexible & able to handle loads better. As mentioned above, get out a calculator and add up the rated ampers of the devices/equipment it will serve power to. Wire is very expensive, so only buy the gauge that you need

14 ft refers to the length of travel from the battery to the fuse panel. 100 amps is the max capacity of the panel. Individual circuits will be fused by the amperage required for each device. So #8 or 10 will be more than sufficient.

You are doing one thing wrong here. Fuses are there to protect the wiring. You're talking about running 14 feet of wire that isn't protected. You should have the fuse within 7 inches of the source of power. Or if wiring is in a sheathe the fuses can be 40 inches away. You should never run unprotected wires. The only wire not required to be protected is the positive lead from the battery to the starter. Everything else is required to have circuit protection.
See: newboatbuilders.com/pages/elect.html

Also here are links to two graphs on how to figure out wire size based on load and length. newboatbuilders.com/pages/elect2.html and newboatbuilders.com/pages/elect2.html The first is to find size based on load and the second is to find size to minimize voltage drop. For the first on you need to know how many amps the wire will carry. Use the column for 105C degrees, the most commonly used temperature rating. The once you have sized it for the load look at the voltage drop table. You'll probably have to go up one size.

Thank you!! That is an excellent resource!