Electrical Do-It-Yourself

By Frank Lanier

Hopefully, you won't find any of these cringe-worthy mistakes on your boat.

There's no shortage of people who can do a good job slapping on a coat of paint or tuning up an engine. But based upon marine surveyor Frank Lanier's experience inspecting boats, the pool of qualified folks with the skill level to make electrical repairs and installations gets a lot smaller.

Jethro's Sure-Fire Patented Electrical Connection

  • Bad battery cable connection

    Uh Oh!

    Good battery cable connection

    Done Right!

Boaters are a creative lot when it comes to solving problems afloat. Not only is the homegrown junction splice used in the positive battery conductor at left nonstandard, it also leaves an energized bolt to arc and spark while bouncing around the engine compartment — a real fire hazard.

Bonding System

  • Bad bonding

    Uh Oh!

    Good bonding system

    Done Right!

Here we have a hose clamp being used to secure a bonding wire to a seacock, an installation that is as ineffective as it is unorthodox. While the pros and cons of having a bonding system installed are often debated, one thing is certain: if one is installed, all connections must be tight and corrosion-free for the system to work properly. One that's improperly installed or maintained will provide the worst of both "to bond," and "not to bond" worlds, and your thru hulls won't be protected.

Sterndrive Corrosion

Here's proof that sterndrive owners are caring, giving folks. If your marina neighbors have grounding, bonding, or other such wiring issues, your aluminum drive will give of itself, acting like a huge sacrificial anode to protect their below-the-waterline metals. As aluminum is low on the galvanic pecking order (being less noble, it's more likely to corrode than most other metals), always ensure your sterndrive's sacrificial anodes or corrosion suppression systems are present and operational.

Wiring Gone Awry

  • Bad wiring

    Uh Oh!

    Good wiring

    Done Right!

The only thing worse than dealing with an electrical issue is having to wade through a jumble of loose, unorganized wiring before even beginning the troubleshooting process. Unsupported wires and cables can bounce around while underway, causing plenty of electrical issues, ranging from broken connectors or wires (such as the brown wire shown in the center of the left photo) to gremlin-like intermittent problems that seem to magically appear and disappear with no rhyme or reason. Worse, they can chafe and cause a fire.

Battery Basics

  • Bad battery red and black mixed not secured wing nuts

    Uh Oh!

    Good battery installation

    Done Right!

Industry standards call for batteries to be installed in liquid tight, acid-proof boxes or trays, be properly secured (movement no greater than one inch in any direction), and have all exposed positive terminals covered to prevent accidental shorting. All good recommendations, but sadly none of them are met in this particular installation. Another recommendation is that no battery cables and conductors 6 AWG and larger be connected to the battery with wing nuts. They're difficult to properly torque and may work loose due to vessel movement. Use marine-grade nyloc nuts instead. Keep in mind that a battery is a really just box of electricity, and if it gets loose, sparks can fly and ignite something flammable nearby.

Homemade AC Power Cord Adaptor

  • Bad shore power adaptor

    Uh Oh!

    Good adaptor plug use

    Done Right!

Need AC power aboard but don't want to fuss with those frilly, unnecessary add-ons like plugs, breaker panels, and permanent wiring? Don't simply take a 30 to 15 amp adapter, cut the end from a three plug extension cord, then tape the wires to the prongs at the 15 amp end (no need for that fancy, electrical grade tape either). Waaalllah — problem solved. Not. This is a fire or electric shock just waiting to happen.

Battery Switches (The Fine Print)

  • Bad battery switch

    Uh Oh!

    Good battery switch

    Done Right!

Yes, we all know that battery switches need to be mounted — but does that mean the structure the switch is mounted on has to be mounted as well? Isn't the intent of the requirement met regardless? This is obviously the type of philosophical question this boat owner felt should be left up to someone else. The wires from the switch to the battery are guaranteed to come loose eventually, with the potential for sparks and a fire.

AC Plug Installation

  • Bad AC-plug install using ROMEX solid wire

    Uh Oh!

    Good AC-plug install

    Done Right!

Many DIYers don't know that residential style solid copper wiring (aka ROMEX) is not recommended for use on boats. Solid wire is susceptible to breakage due to vibration — the reason marine-grade wire is constructed of multi-stranded copper wire.

Crowded Battery Terminal Post

  • Bad battery terminal post connections

    Uh Oh!

    Good battery terminal-post connections

    Done Right!

How many wires can you connect to one battery post? More than you should, as this photo aptly illustrates. ABYC recommends that no more than four conductors be secured to any one terminal stud. Too many connections create the potential for heat or worse, arcing, that could start a fire. A better option here would be to relocate these connections to an appropriately protected fuse or breaker panel.

Fuse Protection

  • Bad bilge pump installation no fuse

    Uh Oh!

    Good fuse

    Done Right!

DC-powered equipment installations always require fuse or breaker protection. In some cases it's acceptable to power equipment via a connection directly to the battery, but always ensure a properly sized inline fuse is part of the installation. Without a fuse, the wire carrying current to the device can ignite if there is a short in the device. 

— Published: April 2016

Seaworthy, the damage-avoidance newsletter, is brought to you by the BoatUS Marine Insurance Program. For an insurance quote, please call 1-800-283-2883 or apply online at BoatUS.com.


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