Electrical, DC Distribution Panels, Part 1: Analysis and Installation

The three new DC distribution panels, installed above the mahogany spice rack
The importance of the DC (Direct Current) distribution panels on a cruising sailboat cannot be overestimated. These panels control many important circuits in and around the boat. There are those circuits that concern navigation lights, anchoring lights, and the GPS and VHF. There are those that concern the lights within the boat. Finally, there are those for all the miscellaneous, yet important items, such as fans, DC receptacles, and one thing then the next. Many cruising sailboats have large, multi-circuit DC distribution panels. Yes, these are convenient - for those who have the space. For those who don't, in other words, for those whose vessel would rightly be classified as pocket cruiser, often large DC panels are not a possibility. In these instances, two or more small DC panels can serve the same purpose. The advantage, of course, of small panels is that you can arrange them in creative ways. In the rewiring of Oystercatcher, my Ericson 25, I had no choice but to get creative with the placement and orientation of the three DC distribution panels that I installed. In this two-part article, I describe my rationale for my placement and arrangement of these panels, and I describe my wiring of them with regard to the runs that were made from each of these panels to the terminal blocks (which would feed the individual circuits).
The original DC distribution panel was woefully inadequate, except to those with the most Spartan of tastes.
The electrical system in general was also woefully unsafe, at least on the boat that I purchased. For more on the problems that I inherited when I purchased this boat in 2009, see my article, "Electrical, Original."
In terms of the inadequacy of the original DC panel, let's take a look at what it had to offer. As you can see from the labels below, it allowed for only the most rudimentary functions.
This is certainly why the previous owner, or possibly the original owner (the boat had only two before me), installed the items you see below - a bilge pump switch, and a second panel.
These were located next to the lazarette door.
The second panel, i.e., the one located next to the lazarette door, appeared to have been purchased second hand. The owner had re-labeled the circuits with one of those vinyl-tape-stamping guns that was popular back in the 1970s and early 80s. Note that the label for the circuit at the bottom is partially missing. The original label (what is visible of it) says, "windshield." My guess is that this panel came off of a powerboat of some sort. There's no problem with using second hand equipment. There is a problem, though, with wiring it in a haphazard, numbskull way. Some of these switches worked, some didn't. Some controlled things that were not indicated by the labels. Moreover, the guy had placed this on a bulkhead, the backside of which opened to the lazarette. Putting aside the fact that the wires from the panel made for a messy and unusable lazarette on the port side, the exposed switches were dangerous on account their proximity to the battery. Flooded lead batteries emit gas when they are being charged. With a high enough concentration of gas and with an electrical device that is not ignition protected, the results can be . . . well . . . explosive.
It was probably for these reasons that Ericson located the original panel higher up on the bulkhead, on the same level as the stove. That way, the wiring on the backside of the panel would be within the port side cockpit locker. In terms of locating the original panel on the stove side of the galley instead of the sink side, Ericson probably opted for the galley side in order to keep the panel away from the water on the sink side. For all of these reasons, I stuck with Ericson's original location, when the time for me to install most of the components of my new electrical system. As you see in the picture below, I filled that bulkhead with quite a few items - an AC receptacle, a battery switch, a battery monitor, a DC main circuit breaker, an AC distribution panel, and above that, two bilge pump switches. Knowing that by installing all of these items on this bulkhead I would have no room for the new DC distribution panels, I had planned in advance to locate those panels on the alcove box just above the mahogany spice rack. Before anyone raises an objections to my choice to locate all of this electrical equipment so close to the stove, I will say right now that I would later take measures to protect it by means of a high-tech, fire-resistant curtain of sorts that could be snapped into place when the stove was in use.
In terms of locating the DC panels in the alcove box, it sounds simple right? Simply cut three holes in the wood that covers the alcove box, install the DC panels, and you're good to go, right? Not so fast. In my experience in the refitting of this boat, nothing is ever that simple.
The problem was that the wood that covered the alcove box was one continuous piece of mahogany trim. This trim piece ran from the galley to the end of the main salon. Sure, I could have installed the DC panels in this trim piece, but it would have been incredibly awkward and difficult to wire these panels while having to deal with an eight foot long piece of wood flopping around here and there. So why not just cut the trim piece? That would solve the problem, wouldn't it? That way, part of the trim piece would be over the stove, and the other trim piece would be over the settee in the main salon. Yes, two separate trim pieces would do the trick. Not so fast.
The problem was that there were cut-outs in the fiberglass underneath the trim piece. These cut-outs did not correspond in any way to the break between the galley and the main salon. This meant that if I wanted to cut the original mahogany trim piece, I would need to cut it to correspond to one of the cuts-outs in the fiberglass. As you seen in the picture below, the first cut-out extends about one foot beyond the stove. This stove serves as a natural break between the galley and the main salon (never mind the temporary counter extension you see in the picture below). From a design standpoint, it would, in my opinion, look strange for the mahogany trim piece to extend all the way into the main salon. It would also look strange for the DC panels to extended into the main salon space. I thought about this and thought about this, and drank more than a few bottles of hops and barley before reaching the solution that I eventually reached. That solution called for the creation of a trim piece for the trim piece. A new trim piece that extended the length of the space (from the galley through main salon) would cover the existing cut-outs in the fiberglass. This would eliminate these cut-outs as an issue. This would leave me free to cut the original mahogany trim piece in a way that would emphasize the break between the galley and main salon.
I wanted the new, foundational trim piece to be of a different color than the original mahogany one. I selected luan, a wood from the tropical Pacific that is often used as an underlayment in household kitchens. Luan is not a finish-grade wood, so my plan was eventually to epoxy-coat it and paint it white, so that it would correspond to the white of the alcove box itself. In terms of cutting the new, luan trim piece, I began by laying the original mahogany piece on top of the luan. The mahogany served as a pattern of sorts. The new, luan trim piece would be half an inch larger, all the way around. As you see in the picture below, I had to orient the mahogany in a diagonal fashion, in order to get it to fit on this sheet of luan (which was 4 feet by 8 feet in size).
Below, you see the half-inch marks that I've made on either side of the mahogany.
Notice in the picture below that I have drawn one of the ends two or three inches beyond the original mahogany. My reason for doing so will become clear as we move further along in this posting.
The cutting of this new, luan trim piece was not easy. Before I made the final, precise cuts, I made several initial cuts to get rid of the large pieces that would hinder my access to the pencil-marked lines.
I then loaded my Makita jig saw with a Bosch brand T101BR, 10 TPI (Teeth Per Inch) reverse-cut blade. These blades are designed for making especially clean, splinter-free cuts. I should note that these are the same type of blades that I used elsewhere in this refitting of the boat for cutting fiberglass. The reverse-cut blades reduce the chipping of the gelcoat.
The Makita jig saw, like other good jig saws, has several different settings. I set it to zero, which would prevent the blade from making oscillating plunges, and would instead make the blade cut straight up and down. This meant that it would take longer for me to make the cut. The reward, however, would be a much cleaner cut.
Also I set the speed to #2, one of the Low settings. This would also help the blade made a cleaner cut. This step and the one I described above are ones that I would always make when cutting fiberglass on the boat. I should note, though, that after making a practice cut in the luan, the #4 setting worked better in terms of preventing chips and splinters.
I had to use dumbbells to weight down the luan along its center, since it was impossible to clamp this part of the wood.
It took a long time for me to make the first cut, but it was worth it. No chips, no splinters.
Then I turned the piece around and cut the other side.
After I had finished making the cuts, I loaded up the quarter-sheet sander. I experimented with several different grits on a scrap piece and came to the conclusion that 100 grit was the best for these purposes.

Next, I grabbed the original mahogany trim piece and laid it upon the new one. I situated the mahogany piece so that it would be one half inch from the right side (the far side, as seen in the picture below). On the left side (the near side, in the picture below), I allowed 2-3 inches of luan to be exposed. I wasn't concerned about the mahogany being at an inconsistent distance on this left side, because I would soon be cutting the mahogany to make room for a piece of Spanish cedar, which would serve as the foundation for the three DC distribution panels. At any rate, after I had lined up the luan and the mahogany in the appropriate fashion, I drilled a few holes through them. I would use these holes to screw these pieces into place, temporarily.
The luan and the mahogany were quite unwieldy. To assist me in screwing these two pieces into place, I called upon the Admiral.
With a little cussing here and there, we wrestled the two pieces into place and held them there long enough for me to get the screws in place.

Using the side of the mahogany spice rack as a guide, I made an initial mark on the bottom of the mahogany with a pencil. Then, I pulled out a plumb bob and allowed it to hang over this mark. At the point at the top of the mahogany, where I held the line, I made a second mark. No pictures of this, of course. Had to have two hands.
Back at the sawhorses, I used the speed square to mark a straight line between the two pencil marks. See the bottle of vitamins? I used this to scribe an arc on the two corners.
The vitamin bottle worked well. The new, rounded corners looked just like the old ones at the other end of the trim piece.
Now that I had removed the unnecessary mahogany from the luan, I could get to work on the Spanish cedar that would serve as the mounting surface for the three DC panels.
Why Spanish cedar, and not mahogany? Well, it was actually the result of a mistake. As I have said in other articles, I frequently visit Southern Lumber, a traditional lumber yard here in Charleston, South Carolina. The yard has quite a few different warehouses. One is devoted exclusively to exotic woods. In the picture below, you can see a two-tiered rack were some of the exotics are stored. The sapele mahogany, which I often buy, is located on the bottom right of the rack. There are also usually one or more large stacks on the floors. Notice the scrap pile to the right of the rack. There is where they throw random pieces of various exotic woods that are left over from the millwork division of the company.
Every few weeks they have enough of these random scraps to make a big stack on a pallet. They then sell the whole pallet for two or three hundred dollars. Before this time, they will sell individual pieces, sometimes at nice discounts, if they are of an especially odd size or thickness. I like to dig through the piles, looking for sapele mahogany. There's a nice 8/4 piece, about two inches thick, right there on top of the pile in the picture below. One day, while picking through a pile like this one, I found a few good pieces, bought them, and took them back home. Some time later, when I needed to use these pieces for something, I pulled them out and inspected them, trying to figure out which one would make the best piece for that particular job. It was then that I noticed that one of them was not exactly like the others. Upon closer inspection, and after a little bit of research, I figured out that this slightly different piece was not sapele, but instead Spanish cedar. Despite it's name, Spanish cedar is actually a member of the mahogany family. They look very similar. Spanish cedar, though, is somewhat lighter in weight. At that time, I put the Spanish cedar aside, deciding that maybe I could use it for some other project.
When it came time to select a nice piece of wood for mounting the three DC distribution panels, it just so happened that the piece of Spanish cedar was just the right size for the job.
The first problem I had to solve was how to make the squared-off piece of Spanish cedar fit onto the curved piece of luan.
The only solution that I could find was to cut the Spanish cedar into the shape of a parallelogram. You can see in the picture below that the squared-off look did not look good.
While marking the first end of the soon-to-be parallelogram, I went ahead and scribed the corners with the vitamin bottle. That way, I could cut the entire end in a single pass with the jig saw.
The finished cut on the first end.
Placing the Spanish cedar back down upon the luan trim piece, I was able to mark the other end.
Here's the way it looked after I had finished cutting both ends.
My next task was to make a cut-out within the luan trim piece. This cut-out would create the space needed for the backs of the DC panels.
Also at this time I thought through how I might be able to gain access to the backs of the DC panels after they had been installed. In the picture below, you see a hinge on the back of the Spanish cedar. My thought was that I would simply swing the Spanish cedar open and shut. While this sounded like a good solution, I ended up abandoning the idea. I didn't like it that the Spanish cedar would not sit flush with the luan trim piece. The problem would have still existed, even if I had mortised the hinges within the cedar, since one half of the hinge would still be sitting on the surface of the luan trim piece. I also would have had to have come up with some way to latch the Spanish cedar shut, and there was nothing nearby (within the boat) onto which I could have latched it. Why so picky about the gap between the Spanish cedar and the luan, other than the fact that it looks cheap and lacking in craftsmanship? I didn't want any air to flow freely between the alcove box and the galley and main salon. The interior of the boat would be air-conditioned at night in the summer when at anchor. I did not want any of that precious cool air to escape. Moreover, I did not want any of that hot and unpleasant air from the cockpit locker (which was connected to the alcove box) to be drawn into the living space within the boat.

In place of the hinges, I opted for stainless steel screws with finish washers.
These would hold the Spanish cedar tightly against the luan trim and the alcove box. They would also complement the other screws and finish washers that would be on the mahogany trim piece.
The cut-out, soon after I had completed the job. The luan was flimsy, and I had to be especially careful when making the cuts.
Back in the boat, with the luan and the mahogany reinstalled, I was able to mark the small piece of fiberglass that needed to be removed from the original cut-out. You should see clearly now why I needed to make the luan-trim piece 2-3 inches longer than the mahogany original. The original did not extend all the way to the end of the galley. I wanted the luan and the Spanish cedar to extend all the way. This would make them more visually appealing. The Spanish cedar would be the same length as the mahogany spice rack underneath it. The cedar and spice rack would thus visually complement each other.
In the picture below you can see what I'm talking about. Balanced and harmonious, the Spanish cedar and the mahogany trim piece help to define the galley area and set it apart from the main salon.
One more way that I planned to achieve balance was through the placement of the three DC distribution panels. The three panels, evenly spaced, would complement the three compartments of the mahogany spice rack.

I began by drawing three rectangles, evenly spaced (and square with one another) across the face of the Spanish cedar.
When I put the Spanish cedar back in place within the boat, the rectangles, as I drew them, looked odd to me, since the luan trim piece, on which the Spanish cedar was mounted, was curved.
I returned to the sawhorses and began to experiment with different orientations for the three rectangles.

As much as I tried, I could not make the rectangles look good when they were canted one way and another.
See what I'm talking about?
After wasting about half an hour on this fruitless enterprise, I redrew the rectangles as I had drawn them the first time.
Then I got to work, making the cut-outs for each panel.
The first one was different from the others. This was an older West Marine brand panel with glass fuses.
The other two were newer versions of the first one. West Marine had moved from fuse-based panels to panels with breakers. With the switch, they had also changed the outer appearance slightly.


The finished cut-outs.
The panels, temporarily installed.
The backside of the panels.
While all of this was going on, I was also working on the installation of the AC distribution panel and the other items that I placed on the bulkhead.
I still needed to cut out that small piece of fiberglass from the original cut-out in the alcove box, so I removed the spice rack and covered up the electrical items to protect them from the fiberglass dust.

You can see some of the original wiring that still lurked within the alcove box. Some of the original wiring I had left in place, simply for the sake of letting me see how Ericson hat routed various wires long ago. I figured this might help me with some of the ideas I was formulating for the routing of the new wires.
My first impression upon installing the DC panels was that the entire port side galley area looked balanced and well-organized. I was, though troubled by the fact that the Spanish cedar did not fully conform to the alcove box. It's impossible to see from this angle, but there was a gap of about 1/8 inch between Spanish cedar and the luan around the mid-section of the Spanish cedar. The problem was that the alcove box curved not only upward, but also inward. Yes, it was concave, conforming to the curvature of the hull. This meant that the Spanish cedar, being a straight board, did not conform.
The only way I knew to correct this was to install more stainless steel screws with finish washers. To do this, I had to remove the mahogany spice rack. Otherwise my Makita drill would not fit. I made a mental note to myself that when sailing I needed to carry my Milwaukee Tools, right-angle attachment. Otherwise, I would not be able to access the backside of the panel easily, if necessary.
The finished installation, dry-fitted into place. The additional screws did a great job helping the Spanish cedar conform to the curvature of the box and thus the hull. The task before me now was the wiring of these panels to the terminal blocks, which were located within the alcove box. That is the subject of part two of this article.
This ends this posting on how I installed the new DC distribution panels in Oystercatcher, my Ericson 25.

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