Electrical Systems

Manufacturer Requirements

This section deals with isolation of an electrical component using open spaces and minimum
distances. The previous two sections discussed bulkheads, and decks or special enclosures, respectively.

Ignition protection is not required for electrical components that are in a space that is open to the atmosphere and is located at least two feet from a gasoline fuel source. The term “open to the atmosphere” is defined as a space or a compartment having at least 15 square inches of unobstructed area opening into the compartment for every square foot of compartment volume. Open boats, such as runabouts, with the engine aft and the fuel tank located far enough forward to meet the two foot provision will be able to use non-ignition protected components in their instrument panel. Figure 8 depicts a typical open boat, whose bow compartment is open to the atmosphere, with a two foot distance maintained between electrical components and the gasoline fuel source. Figure 4 shows a saddle tank installation with a two foot distance between electrical components and the gasoline fuel source.

FIGURE 3 - Isolation of Electrical Components

FIGURE 4 - Isolation of Electrical Components

FIGURE 5 - Isolation of Electrical Components

FIGURE 6 - Isolation of Electrical Components

FIGURE 7 - Isolation of Electrical Components

Partial Bulkhead - Foot board, Toe board - In figure 8a,b,c, we see how boat structures such as a partial bulkhead may be fitted to increase the distance between the source of fuel and the source of ignition.

FIGURE 8a - Isolation of Electrical Components

In figure 8a, the switches in the dashboard are within 2’ of the fuel deck fitting, and also within 2’ of the fitting at the fuel tank. Each of these fittings is a potential source of fuel leak. In this installation, all switches would have to be ignition protected.

FIGURE 8b - Isolation of Electrical Components

Here the builder has fitted a partial bulkhead across the boat, behind the dash to increase the distance between the fuel deck fitting and the backside of the dash. The builder has also decked over the front of the tank so that the tank fitting is also more than 2’ from the back of the dash.

FIGURE 8c - Isolation of Electrical Components

Here there are three potential sources of fuel: The vent fitting in the side of the hull, the fuel deck fitting, and the connections at the tank. The vent and fill fittings are more than 2’ from the dashboard. The tank fittings were too close to the dashboard. Here the boat builder has installed a foot board to increase the separation from the dashboard.

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