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12-Volt Mast Wiring: Common Issues

In my last article I discussed some of the more common failure issues with mast light fixtures. Associated with this 12-volt system is the wire run in the mast. Common problems here are improper wire types, their age, and their terminations. If we think in terms of the average age of the recreational sailing vessel we will find; original wiring, aged wiring, corroded wire connections, and improperly replaced wiring. If the vessel is twenty years old for example, we can find that the wiring system is original from the mast manufacturer. The following issues may be problematic.

The insulation protecting the wires is usually found to be in poor condition. Cracks or worn areas obviously contribute to a short circuit. Depending upon the sophistication of the mast, the wiring may be loosely run in the mast. This condition exposes the wiring to chafe from halyards and failures at the wire exits especially at the upper connection where the weight of the wire is connected to the masthead. This weight of the wire should be supported by some anchoring system at the top of the mast. This takes the load off of the wire connections in the light fixture itself. A good installation will have some extra protection at the wire exit such as a rubber grommet. The wire then can be secured to the mast head with a “zip” tie that can be affixed with a stainless fastener. Higher quality installations will incorporate a conduit system inside the mast that not only adds protection from internal mast issues but also controls the “slapping” of wires making for less wear and a quiet mast while sitting at anchor. With the mast in the down position a conduit system can be easily installed in older masts.

The connections usually suffer from a corrosive environment causing interruptions in the conductivity of the circuit. In our last discussion we recommended cleaning connections with a Scotch-brite pad and coating then with electrical grease to thwart the effects of moisture. If at all possible the wire connections in the boat should be located on a bulkhead near the base of the mast. Use an actual electrical “dry” box. This offers protection from moisture and a suitable connection component to securely connect the circuitry. This box can be mounted in a way that the wiring is protected from outside forces. Inside the box is a buss-bar with screw clamps. This is the connection of choice rather than a friction fit plug.

VHF antenna connectors are a notorious issue regarding the quality of reception and transmission. Quick-connects or press fittings are a no-no. This connection should be a “solder” type fitting. The soldering technique itself needs to be proper. It takes plenty of time and heat to get all the surfaces to a temperature that allows the solder and surfaces to mate. Usually solder guns are useless in this area. Micro butane torches allow for an accurate aim and proper heating of the connector’s surfaces.

Replacing mast wiring involves selecting proper marine grade 12-volt wire. Be it for lights or the VHF system. This sounds obvious enough but you would be surprised at what we are finding inside masts. Everything from household speaker wire to wires whose insulation mysteriously changes color from the top to the bottom of the circuit. For most mast lights and VHF circuits, marine grade 18 gauge wire and RG6-8X VHF cable are recommended.

Though this all sounds fundamental, most circuits that we test have some issue related to this discussion. In the next article we will discuss the proper use of mast lights as signals to others. If you have issues with your mast circuitry, please contact Torresen Marine to discuss a solution.

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This entry was posted on Monday, December 15th, 2008 at 1:02 pm and is filed under News From Torresen Marine. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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