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12 Volt Wiring Size Quick Reference

12 Volt Wiring Size Quick Reference

Find the correct wire size for any 12V project with easy-to-read tables for 3% and 10% voltage drops.

Regular price $9.18 USD
Regular price Sale price $9.18 USD
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Make Wiring Decisions with Confidence

Avoid the risks of improper wiring, such as equipment damage or fire hazards. The 12 Volt Wiring Size Quick Reference Guide is your go-to solution for choosing the right wire size for any 12V project—whether in your boat, car, or RV. With large, shaded charts for both 3% and 10% voltage drop tables, you can size wires accurately and efficiently. 

  • Includes tables for regular and engine-room installations
  • Durable, waterproof, and grease-proof paper stands up to tough environments
  • Compact design perfect for toolboxes, lockers, or workbenches
How to Use • Step-by-Step with Pictures

Includes More Than Just Wire Sizes
  • Wiring connector sizes and color codes
  • Battery state of charge chart
  • Simple formulas for watts, amps, and volts
Made in USA • Built to Last • Environmentally Friendly

Designed in the USA; printed in the USA on American-made recyclable synthetic paper using environmentally-friendly soy-based inks at a facility that is completely wind-powered. Minimal packaging. Tough enough to handle life on a boat, it won’t tear, degrade, or smear, even in humid or greasy conditions.

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Our Guarantee

At The Boat Galley, we have one mission: to help you cruise with confidence.

 

As liveaboard cruisers, we understand the challenges and questions that come with boat life. That’s why we create practical products and courses designed to tackle the same issues we’ve faced ourselves—making your life on the water easier, safer, and more enjoyable.

 

Try our products and courses for yourself. If they don’t make your boat life better, use our 90-day FREE no-hassle return guarantee.

Raved About By TheatreCat . . .

"Very handy to have onboard for quick reference."

Verified Purchaser, 12 Volt Wiring Size Quick Reference

Thumbs-up icon with stars, representing customer testimonials praising The Boat Galley’s products and resources.

Where You’ve Seen Us

Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.
Cruisers University logo, where The Boat Galley team teaches in-depth liveaboard and cruising seminars.AGLCA logo, representing seminars and resources shared by The Boat Galley team for Great Loop cruisers.American Sailing Association logo, highlighting seminars led by The Boat Galley team for sailors.Boat US Magazine logo, featuring The Boat Galley team’s tips for boat owners and cruisers.The New York Times logo, featuring interviews with The Boat Galley team on cruising and boat life preparation.SAIL Magazine logo, featuring articles by The Boat Galley team about life aboard and sailing tips.Cruising World logo, featuring The Boat Galley team’s contributions on successful cruising and boat life.The Weather Channel logo, highlighting The Boat Galley team’s hurricane prep advice for boaters in live interviews.Spinsheet Magazine logo, featuring The Boat Galley team’s published articles on boating and cruising.Boating Writers International logo, 1st place award for excellence in boating articles.Bluewater Sailing Magazine logo, highlighting articles by The Boat Galley team on offshore sailing.Salty Dawg Sailing Association logo, showcasing seminars delivered by The Boat Galley team for members.SSCA logo, highlighting seminars by The Boat Galley team on successful liveaboard cruising.PassageMaker Magazine logo, featuring The Boat Galley team’s expertise on cruising powerboats.Good Old Boat Magazine logo, showcasing articles by The Boat Galley team on maintaining and cruising older boats.

Meet The Boat Galley Team

At The Boat Galley, we’re all cruisers. We know the joys—and the challenges—of boat life. The steep learning curve, costly mistakes, and hours spent searching for answers can be overwhelming. We’ve been there. That’s why we’ve created practical tools, trusted resources, and real-world guides to help you skip the frustrations and focus on enjoying your cruising life.

Curious about our story and what drives us? Learn more about us here.

Customer Reviews

Based on 5 reviews
80%
(4)
20%
(1)
0%
(0)
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G
Ginger C.
Husband likes it but I don’t understand it

My husband explained the charts to me and now I understand it. Neither of us are electricians.

A
Allen P.

12 Volt Wiring Size Quick Reference

R
Ron H.

Haven’t had time to use it yet; however, I like the color, layout, and charts.