Build your own switch panel

We voyage on an older boat that originally had only basic fused electric circuits: running lights, cabin lights, anchor light, bilge pump and so forth. No DC circuit breakers. As we added electrical equipment over the years, we added several fuse panels, including a fused switch panel for new electrical loads. Eventually, I decided to build my own switch panel from standard, readily available components.

The objective was to build a five-switch panel using a 7-by-5-inch piece of 1/4-inch teak veneer and standard components to fit the holes left by the previous panels. It did not need to be waterproof! I purchased five 1-by-1/2-inch stick-on labels from a local trophy/label maker for $1 each. Total cost of the fuse holders, lighted switches and resistors was $26 from Radio Shack. The teak veneer was $3. I needed 10 3/16-inch and 15 1/4-inch insulated female quick-disconnects to connect to the fuse holder and switch male lugs. Total cost $36.

I used automotive lighted switches because they can handle up to 30 amps at 12 volts DC. Switches and fuse holders require a standard 1/2-inch round panel hole and 1/4- and 3/16-inch female quick-disconnects to connect to the switch and fuse holder male spade lugs. The switch lights are unnecessarily bright and use 0.545 amps of current when lit. I added a $0.50 100-ohm resistor in series with each ground (earth) male lug on the switch to dim the light and lengthen bulb life. With the 100-ohm resistor, the light current drops to 0.098 amps. Next I attached a 12-volt No. 8 wire bus to the back of the fuses and a No. 18 ground wire bus to the earth side on the switch with the 100-ohm resistor in between. Then I led each circuit to the center post of the switch.

Since I built the panel on the boat using “boat tools,” I was particularly careful about component alignment. I didn’t want to look at misaligned components day after day. The trick was to cover the good side of the teak veneer completely with masking tape and use a pencil and a ruler to lay out the components on the tape. When all the components were laid out, I scribed the center holes for the fuse holders, switches and mounting screws with an ice pick. I used previous panel mounting hole spacing since the galley bulkhead already had holes. The next step was drilling pilot holes in the panel, gradually enlarging them to 1/2 inch, being careful not to split the teak veneer. Then I removed the tape, mounted the components and located the labels carefully. Teak trim around the 1/4-inch veneer edges finished the job.

After that, I began wiring the panel. The fuse holders required 3/16-inch female quick-disconnects, and the switches took 1/4-inch female quick-disconnects. The 1-watt 100-ohm resistors have a female 1/4-inch quick-disconnect crimped to one end and attached to the ground (earth) male lug on the switch. The other end of the resistor was wired or soldered to the panel ground bus. The 3/16-inch quick-disconnect was attached to the end lug on the fuse holder and wired or soldered to the 12-volt panel bus. A jumper wire was made up between the side male lug on each fuse holder and the 12-volt male lug on the corresponding switch.

As a spare I bought a sixth switch, since Radio Shack isn’t everywhere we cruise.

Dick de Grasse is a frequent contributor to Ocean Navigator.

By Ocean Navigator