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While the principles of electric theory are the same w hether on shore or

afloat, the conductors and the methods of conductor installation...differ

considerably from those used shoreside.

Marine AC:Electrical Wiring Basicsby Scoff Hen y

If your boat can accommodate most householdelectrically-powered conveniences, it undoubted-

ly has two entirely separate electrical systems.The direct current (DC) electrical system derivesits power from your boats storage battery or bat-

teries. In addition to providing starting power forthe engine, DC electrical power is used for bilge

pumps, running lights, the water pressure pump,DC lighting and other related equipment.

The source of power for your boats alternating

current (AC) electrical system is either a shore-side connection or an on-board AC electrical gener-ator. This system provides electricity for appli-

ances and fixed AC electrical equipment aboardthe boat.

While the principles of electric theory arethe same whether on shore or afloat, the conduct-ors and the methods of conductor installation, aswell as many of the appliances and AC electricalequipment used aboard boats, differ considerably

from those used shoreside.Because of color coding and polarity require-

ments, working with your boats AC electricalsystem is really not complicated. A grounding

conductor, or ground wire, in an AC system is al-ways green. The neutral wire or grounded conduct-or is white. The ungrounded conductor, or hot

wire, is identified by any color other than greenor white and is usually black or red.

ABYC (American Boat and Yacht Council)standards require that marine AC electrical sys-tems be polarized. A polarized system is one inwhich the hot and neutral wires are connected in

the same relation to all terminals on all devicesin the circuit.

For example, receptacles are connected so thatthe neutral wire attaches to the terminal identi-fied by the letter s, normally a silver color.

The hot wire should be attached to the brass orcopper terminal. The green colored grounding wire

is to be attached to the ground terminal on thereceptacle.This procedure insures that the proper polar-

ity is maintained and that the electricity willflow safely, without restriction, through eachcircuit. Terminal screws are usually color coded

for easy identification.In all marine electrical applications, avoid-

ing the entrance or accumulation of moisture is ofprime importance. Junction boxes, receptacles,

panelboards and other enclosures in which electri-cal connections are made should be weatherproofor installed in a protected location. All current-

carrying conductors should be routed as far awayas practical from areas where water or moisturemay accumulate.

The conductors used in marine applicationsmust be made of stranded copper wire. The black,

white and green ground conductor in each cable orcord must each be of the stranded wire variety.Household conductors, on the other hand, have a

single, solid core wire. The number of strandsrequired in each conductor in marine applicationsis directly related to the conductors diameter

and the degree to which the wire will be sub-jected to flexing through movement or vibration.The conductors proper size and diameter is alsodetermined by the demand or amount of current

the conductor must carry.Good household wiring often travels through

the house in metallic tubing called conduit. Theconduit supports and protects the wires withinthe walls and ceiling of your home. But on your

boat, conductors are supported throughout theirlength by a self-draining loom or are secured

every eighteen inches by straps or clamps. Inareas other than the machinery compartments ofyour boat, nonmetallic straps or clamps are idealfor holding conductors firmly in place. Metalclamps lined with an insulating material to mini-

mize damage from chafing are used in machinery

areas.Another major difference between household

wiring and the AC electrical wiring aboard your

boat occurs when two conductors or wires arejoined together, or a conductor is connected to a

terminal on an appliance, receptacle or circuitbreaker. A common practice in household wiringis to splice wire to wire by means of electrical

tape or wire nuts. Wire nuts or twist-on connectorshave no place aboard a boat.

Joining conductor to conductor in marine appli-

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cations is best accomplished through th e u se ofinsulated, solderless crimp-on connectors. Thecrimp-on connection may be covered with electri-cal tape, but under no circumstances should

electrical tape be used to join two conductorstogether . Besides assur ing continuity of current,

cr imp-on connectors prevent the conductors f rombeing pulled apart when flexed.

Working with a boats electrical system issomething many boat owners refuse to do because

they consider i t myster ious. More than any other

system on your boat, the AC electr ical system is

standardized. By having the proper tools, follow-

ing the safety tips outlined earlier and using onlymarine electrical equipment, wiring your boat for

AC current can be relatively simple. n

The aufhor, Scoff Hen y, is fhe sales manager forMarinco, a leading manufacturer of marine electri-cal systems and equipment fhaf is designed for

ease of installation, for practicdify, and for along service life in the marine environment.

Marinco, 92 Hamilton Drive, Ignacio, CA 94947.

Pictured are some of the basic tools andsupplies that make wiring aboard aboat an easy task. In addition to the

items shown, you may have occasion touse an electric drill and a saber saw,particularly when youre addinganother shore power cord or a newreceptacle.

A. Multipurpose Tool. This tool a llowsthe insulation to be easily strippedf rom wires without damaging the wireconductors. The same tool is used to cutwire and to crimp the insulated, solder-less connectors on to the wire. For opti-mum connections, the crimping tool

should be compatible with the insul-ated connector (tool and connector fromthe same manufacturer).

B. Wire Cut ters. This form of p liers isstrictly used for cutting wire conductors.Their shape and design makes themideal for performing clean, even cuts ofmulti-stranded marine wire.

C. Screwdrivers. Both Phillips headand straight slot screwdrivers.

D. Tester. To check that all current isoff before you begin to work on AC elec-

trical items.

E. Crimp-on Connectors . Available in avariety of wire and stud sizes, theseconnectors cr imp on to multi-s trandedwire and fasten securely to the terminalscrews of receptacles and breakers.

F. Cable Clamps and Support Clips.Available now in nylon or m etal withrubber insulation, cable clamps are aneffective way to support wiring.

G. Electrical Tape. It is a good practice

to apply electrical tape around thewire and the insulation of the crimp-onconnector to prevent moisture fromenter-ing the connection. Electrical tracertape comes in a variety of colors and canbe used to identify various circuits.

What You Need Before You Start