Boat Horns

The ability to audibly signal the presence of your craft on the water is a legal requirement. The most common way this is done is with a horn. Most boat horns run off of 12 VDC. The sounding mechanisms they employ are an electrical diaphragm (like a car horn), a piezo (like an emergency buzzer) or an air diaphragm with a compressor (like a truck or ship horn). AFI is the leading supplier of boat horns in marine electrical. A horn is a crucial safety feature when a sudden warning needs to be given, to signal trouble, or when underway with low visibility such as in fog. Boat horns are available from several well known suppliers, the most famous in marine being the AFI division of Marinco. As the say on their website, they are
...the leading supplier of horns to the marine industry, with over fifty years of experience in designing and manufacturing sound devices specifically for use in harsh marine environments. Stainless steel is used for all critical components such as trumpets, motor cover, diaphragms, and assembly and mounting hardware. In the case of the XLP trumpet horns, the horn is given extra protection through the complete over-molding of the internal motor cover housing. It is this extra process that provides the added protection needed to back up the five-year warranty. AFI offers a complete line of marine horn products designed to meet almost any need, including electric and air trumpet horns, compact horns, electric and air below deck horns, and a comprehensive line of drop-in horns with a wide assortment of grill options.

Battery Boxes

Attwood is the world's most well know manufacturer of battery boxesBattery boxes are used to secure the batteries on a boat against the extreme movement of the craft on water – a marine industry standard and a Coast Guard rule.

While batteries may sometimes be mounted on trays, they are more often stored and held in marine electrical battery boxes, which, besides keeping the battery in place, also protects it from exposure to outside elements like moisture while also containing the corrosive acids of the battery.

Battery boxes also make moving and transporting the battery safe and easy. Battery boxes normally include a box with molded handles, a lid, a strap to hold down the lid and mounting hardware.

Battery boxes are available from several marine manufacturers, although the most well-known are built by Attwood Marine.

Marine Wire

by Allied Wire & Cable, Inc.

The marine environment is a hostile one for electrical wire. Wire used on board a marine vessel will potentially be exposed to numerous obstacles, such as salt water, sunlight, heat and other outside hindrances. All electrical wires are not constructed to endure the problems associated with marine conditions and therefore will not be suitable wiring on boats or ships. In these situations, marine wire or boat cable may be necessary.

Marine wire, boat cable, and marine primary wire are terms you may have heard used in reference to electrical wiring for boats or marine vessels. Wiring specified as "marine" or "boat" is different in several ways from other types of electrical wire, such as power wire used in the home, or automotive wire, etc. A main difference is that the conditions surrounding marine installations require marine wire and boat cable to perform better than other wires designed chiefly for land use.

A marine wire is specifically designed and engineered for the electrical wiring of boats and is intended for all possible uses abroad a ship. Marine wire may be distributed to the pleasure boat and commercial marine industries and is often used by boat builders. The term "boat cable" may often be used interchangeably with marine wire or marine cable. Boat cable usually refers to general electrical wiring used on a boat. Marine wire that may fall into the sweeping category of "boat cable" often starts as a single conductor cable. Extra wires are added from there into one cable, consequently creating multi conductor boat cable.

Because of the demanding marine environment, approved marine wire usually possesses a copper conductor. In addition, the jacket of the cable will most likely have been tested for flammability safety. The jacket and the insulation should be rated water resistant.

The most frequently requested single conductor boat cable styles are marine primary wire and marine battery cable. The cables are extremely similar. The main factor that differentiates the two is the AWG size of the cable. According to General Isles Marine, single conductor boat cable in sizes 16 AWG up to 8 AWG are widely known as primary wire sizes. The larger single conductor marine cables ranging from size 6 AWG up to 4/0 AWG are known as battery cable sizes.

Often times, marine wire and boat cable provided by a manufacturer or distributor will meet the requirements of UL, SAE, Coast Guard, ABYC, and NMMA. The American Boat and Yacht Council (ABYC), the United States Coast Guard (USCG), the National Marine Manufacturers Association (NMMA) and the Society of Automotive Engineers (SAE) have developed safety standards and guidelines for marine electrical installations specifically serving manufacturers, technicians, and even boat owners.

Corrosion is a primary cause of electrical failures on a boat. In order to avoid the common problem, marine wire and boat cable are built to resist quick decay. In both wet and dry conditions, marine wire needs to behave consistently in order to perform properly. Marine wire, boat cable and marine primary wire may possess PVC insulation for added defense against the elements. After all, they need all of the help they can get.

The remaining links will examine the various types of marine wire and boat cable on the market today.

Common Types of Marine Wire

Marine Primary Wire (Tinned Copper)

Marine Primary Wire may also be listed as Tinned Primary Wire. The copper conductor will usually possess a tin coating which causes the strand to be called "tinned copper." Tinned copper marine primary wire is built to reduce corrosion and prevent electrical failure.

Marine Primary Wire (Tinned Copper) can be used in 105"C marine applications, in the internal wiring of electrical equipment and for general circuit wiring. It is employed for electrical connections in the marine and automotive environments where a tinned conductor is preferred. The marine primary wire may additionally be utilized for motorcycles and other applications requiring a high temperature primary wire. Tinned copper marine wire performs well in all marine environments, even in saltwater.

You may see marine primary wire listed as UL 1426 marine grade wire. Most brands of tinned primary wire will meet the requirements of the US Coast Guard and ABYC, as well as others.

Marine Primary Wire (Bare Copper)

Marine Primary Wire (Bare Copper) can be used in 105"C marine applications, in internal wiring of electrical equipment and for general circuit wiring. The marine primary wire shares many of the same applications and properties as tinned primary wire. However, the conductor is bare copper instead of tinned copper.

SAE Primary Wire

SAE Primary Wire is General Purpose Thermoplastic (GPT) insulated primary wire that corresponds to SAE specifications, generally specifications J1128 and J378. SAE Primary Wire may be used for general purpose marine and automotive applications. It usually has a temperature range of -20"C to 105"C and voltage rating of 50 volts.

Flat Boat Cable

Flat Boat Cable is a multi-conductor marine cable that can be used for marine or brake cable. The boat cable usually meets UL Standard 1426 and UL Style BC-5W2. Flat boat cable also may meet DOT Coast Guard specs. The boat cable has a PVC insulated multi-conductor.

Round Boat Cable

Round Boat Cable is much like flat boat cable. However, round boat cable makes for easy installation where tight, jagged spaces are present. Many installers of boat cable favor round cables because they are easier to arrange. Additionally, round boat cable may be used for harsh environments.

Marine Battery Cable

Marine Battery Cable generally has a temperature range of -20"C to 105"C and a voltage rating of 50 volts. The battery cable also resists oil, fuel and acid. Marine battery cable is designed to survive the harsh marine environments. The cable normally has a high strand count cable with tin plated copper stranding. Marine battery cable may be used in battery installations.

Minimize Electrical Risk

Minimize electrocution risk from an onboard AC electrical system by ensuring that the vessel is properly wired by a professional marine electrician, and inspecting it periodically for damage or deterioration.

If your electrician isn’t familiar with ABYC (American Boat and Yacht Council) standards, find one who is. Use only copper multi-strand wire (preferably tinned “boat cable”), of correct size for the load, with marine color coding.

Hull shorepower inlet

Ensure that all connections are inside a panel box so that it’s impossible to touch them accidentally. Better yet, make them accessible only with the use of tools. There should be no bare wires anywhere on the boat. All connectors must be properly sized “captive” (ring-type) terminals match the size of the screws, with insulated shanks, and should be made of corrosion resistant materials.

Tension relief and drip loops should be incorporated. All AC outlets on board must be three prong type. Appliances should plug directly into three-prong wall sockets, not extension cords, and multiple socket plugs shouldn’t be used on board. Maintain correct polarity by using only approved plugs and if anything in the system has been modified or repaired, check it with a polarity tester. When making up plugs, ensure that the black wire goes to the brass or black screw, the white wire to the silver screw, and the green wire to the green screw.

Service outlets on the exterior of the boat are a potential problem and to be avoided. Never interconnect the AC and DC systems. The green wire must connect to the boat’s bonding system or metal underwater hardware, but the AC white wire must not. Don’t confuse the black insulation on an AC power lead with the negative on a DC system.

When you switch between a generator, inverter or shore power, the grounding connection must switch too. (If the boat is on shore power the green wire connects to the underwater metal hardware of other boats on the same shore power system. This creates a galvanic cell that promotes stray current and galvanic corrosion. A galvanic isolator on the green wire allows passage of AC but not DC, thereby isolating the boat from the others. A more sophisticated device for the same purpose is called an isolation transformer.)

Here are a few more tips for minimizing risk when working around an AC system:

  • Turn off the breaker at the shore power box before disconnecting the cord, and disconnect from the dock end first. Connect at the boat end first and switch on the dock breaker last.
  • Use only tools and appliances with three-prong plugs, and if you must use extension cords temporarily with power tools, use only cords with three-prong sockets.
  • Shut off generator, inverter, and main AC panel switch before working on the AC system
  • If you must work on live AC, do like professional electricians and work with one hand behind your back to avoid touching hot and neutral or ground at once.
  • Remove jewelry, wrist bands, or other conductive items.
  • Protective clothing, including rubber boots, rubber kneepads, and rubber gloves offer some protection from shock. Rubber or plastic insulated handles on tools like pliers and screwdrivers also help.
  • When working on the end of a cord with multiple wires, tape off all but the one wire you’re working on. • Unless you’re trained in marine AC systems, leave it to a professional.