Hi Kevin,

First of all, thank you for all of the time and effort that you put into your website. The boat wiring information that you share is invaluable.

So tell me Mr. Marine Electrical, do my ambitions exceed my abilities?

My wife and I have a small sailboat that we’ve enjoyed for many years. It’s a perfect size for the two of us and can’t imagine anything that would make the boat more fun…with one exception. We find that we are very jealous of our marina neighbors who have shore power. Whether they are using a television, a drink mixer, a vacuum, a toaster, or even a simple battery charger, we start down the “if only” path.

How tough a project is it to add AC power to an older boat? I’m reasonably comfortable with simple household wiring jobs, but have been told that marine AC can be an incredibly complicated and – if not done correctly – incredibly dangerous.

Any suggestions?

Thanks.

Matt

Hi Matt,

No project is too big, not project is too small when “Mr. Marine Electrical” is on the scene!

Seriously, there is a great new product from our partners at EzAcDc that will fit your needs. They have a complete marine shore power system that follows their snap-together philosophy of simplifying boat wiring jobs.

Installation of the new marine shore power system is easy.

The panel is pre-wired and comes with a remote outlet with 10′ of boat cable that simply plugs into a “snap together” plug on the back. The kit is also pre-wired with 10′ of Marine grade boat cable that runs from the boat AC panel to the included shore power inlet.

Best of all, any complex electrical connections are already made inside the powdercoated aluminum box.

All outlets are GFCI protected. And, for additional safety, the AC panel has a dual pole breaker to protect the boater if the dock outlet is wired backwards.

The panel also includes a power “on” indicator light and a reverse polarity light. It also comes with the AC to DC grounding wire that is required by the US Coast Guard. This wire runs from the back of the panel to your DC negative buss, engine ground, or battery negative and provides an additional safety path to ground if you have an AC fault on your boat. Even though required, this wire is redundant on this well-designed system since the GFCI also protects everything.

Additionally, there is a single outlet on the back of the shore power panel to allow a built in AC device to be connected. This is ideal for a battery charger or refrigerator that comes with a standard 15 A household plug. Simply plug it into the back of the panel before installing.

It comes with the industry standard 30 amp Marinco inlet. You can choose between the standard square plastic inlet or upgrade to the stainless steel version. Both will connect to an 30 amp marine cordset or adaptor.

Please let me know how your project turns out. I always like pictures.

Kevin

Dear Kevin,

I am currently beginning my first boat wiring project, a total rewire of a small Owens cruiser from the late ’60s.

Here’s my problem:

The old wiring runs behind the original paneling and headliner. I could try dismantling everything to remove and replace the wires, but am concerned about damaging any of the woodwork. It’s old. It’s gorgeous. It would be a bitch to replace.

I don’t mind leaving the old wiring in place and just running a new harness, but that still leaves the problem of installing the new wires without causing any damage.

Any ideas?

RP

Dear Ron,

Your problem was common with boat restoration projects – until the introduction of Harness in a Can.

Harness in a Can lets you spray pro-quality boat wiring into even the most hard to reach areas. Simply point, spray, and apply power. What could be easier?

And, it’s not just easy, it’s ABYC approved! Harness in a Can sprays out a harness with correct wire color and sizing – and with all of the connections that you need to get the job done fast.

If you order now, you will also receive a cap snaffler – absolutely free. Cap snafflers snaffle caps off any size jug, bottle or jar…and they really really work.

Call now to order. The toll free number is 877-277-3665. Operators are standing by. That’s 877-APR-FOOL.

Kevin.

Hello,

If a European built boat comes to the United States, what is the best way to connect to shore power, i.e., 24/240V Euro to 12/120V American?

Thank you,

Warren

Warren,

If all of your AC appliances are designed for 50/60 Hz operation, then you can solve this with a Step UP transformer that will take the American 120v and up it to 240v.

You will need to research the AC components on your boat to answer this best.

The only connection between your 24v system and shore power is the battery charger. If your charger can handle 50/60 hz, then the Step UP transformer will work for this also.

Hope this helps,

Kevin

Hi,

I was given your email address by a friend who highly reccomended you.

I’m just about to rewire my boat as it’s winter. There are a few things that I would like to know before I start.

What would you suggest as to the thickness of cable from the battery to the 6 gang switch panel? I’m only running the normal things:

• Fishfinder
• VHF radio
• CD player
• Bilge pump
• Lights
• Horn.

I am also wondering if I should put an inline fuse in the live cable between the battery and switch panel and what size fuse?

Any other advice you could give me on boat wiring would be much appreciated.

Many thanks for your help

Paul

Hi Paul,

I am posting a handy spreadsheet that will help you calculate all of your boat wiring sizes.

Once you fill in the blue boxes for total wire length, the sheet will calculate the correct wire size needed for each wire run and for your main panel feed.

You will want to put a fuse or circuit breaker as close as possible to the battery. The size of this will be dictated by the total draw of your panel (Cell C20)

Emergency devices (nav lights, horn, VHF radio, bilge pumps, and blower) are typically wired for 3% voltage drop.

All other devices are usually 10%. Some stereos cannot tolerate 10% and you will need to run them at 3%.

Please let me know if you have any questions,

Kevin