Electrical, AC Distribution Panel, Part 2: Wiring

The AC distribution panel, in the process of being wired
Having described, in Part 1 of this article, the initial installation of the AC distribution panel in the galley of Oystercatcher, my Ericson 25, I now, in Part 2, describe the wiring of this panel.

In the picture below, we see the galley as it appeared after I had initially installed all the major components of the electrical system that would fit into this space. The AC distribution panel is the one with the white breaker switches and the voltmeter, also white in color. This is a Blue Sea Systems brand traditional metal panel, PN 8043.
On the backside of this panel, I had temporarily installed a Blue Sea Systems brand AC distribution panel cover. A protective cover of some sort is required by ABYC (American Boat and Yacht Council) regulations. I figured it was much easier to buy a protective cover from Blue Sea Systems than it was to try to fashion one myself.
This protective cover was in a cockpit locker, along with other important parts of the electrical system. Beneath it, in the lazarette, there were additional important parts.
If you've read my articles on my installation and wiring of the receptacles for AC circuits 1, 2, and 3, then you'll know that I routed all of the three-wire AC boat cables to the cockpit locker, for it was here, of course, that I would join them to the AC distribution panel. Stripping and terminating these wires with adhesive lined heat-shrink terminals was a challenge, given the confines of the cockpit locker.
A buddy of mine, who is slightly smaller in stature, was able to climb down into the locker, putting his left knee on the shelf in the lazarette and his right foot down in the bottom of the lazarette. In this tight position he was able to strip and terminate the wires. It would have been easier, if I had left fairly large service loops at the ends of the AC cables. I did not, however, want a lot of excess wire in the cockpit locker, since that would surely invite trouble.
Here my friend uses the wire stripper to remove the appropriate amount of insulation from one of the 10 AWG grounding wires.
During this part of the project, my Waypoint LED spotlight (pictured left) was a big help. I would use it during other parts of this complete rewiring project.
Almost all the heat-shrink terminals were yellow in color. This color indicates that the terminals are designed for wires that are 10 to 12 AWG (American Wire Gauge). I used 10 AWG wire throughout the AC system, with the exception of circuit 3, where I used 14 AWG. The blue heat-shrink terminals mark this 14 AWG wire. You'll notice that all but three of the wires have ring terminals, whereas two have forked terminals. It was the end of the day, and I had run out of 10-12 AWG ring terminals. For this reason I had my friend use forked terminals for two of the terminations. Ideally, I would have used ring terminals, but under the circumstances I did what I needed to do.
The next day, I prepared the protective cover to receive these wires. The Blue Sea Systems cover does not come with any holes in it. My assumption was that this allowed the individual consumer to customize it as he saw fit, so this was what I did. First, I used a paddle bit to cut a fairly large hole in the bottom of the cover. This would be for the AC three-wire cables.
Then I drilled a slightly smaller hole on the side. This would be for the 6 AWG AC grounding cable.
Finally, I drilled two small holes on the opposite side (the side facing down in this picture). These small holes would be for the wires for the DC powered backlights for the voltmeter and the panel itself.
With this out of the way, I turned to my next task - filling some gaps along the top of the bulkhead on both sides of the galley. For this, I used a BASF product called NP1 - a polyurethane adhesive/sealant commonly found in the construction industry and available in good hardware stores. Like 3M 4200 or Sikaflex, which are also polyurethane adhesive/sealants, NP 1 is strong, but does not form a tenaciously permanent bond like 3M 5200. At about $7.00 a tube, NP 1 is considerable less expensive than 4200 and Sikaflex, and, importantly for this context, it comes in a variety of colors. I picked Off White, which was a perfect match for the interior of the boat.
I started by cleaning the area with acetone. Then I punctured the seal on the tube of NP1 and got to work.
If you look closely in the picture below, you can see the joint that I sealed. It's right where the fiberglass bulkhead meets the fiberglass lip, rim, or cleat (whatever you want to call it).
On the other side of the galley there was a fairly large gap between the bulkhead and the cleat - about 1/4 inch in some places. I did not want air freely moving from the cockpit into the galley through this gap. Therefore, I pumped it full of NP 1. I used about half of the tub filling and sealing this joint, as it was quite deep.
While I was at it, I sealed all the other joints along the bulkhead in this area. It's easy, in the picture below, to see the NP 1 near the AC receptacle. After I was finished, I made sure to clean up the bead and any stray marks with acetone.
With this out of the way, I could focus on the most important task - the wiring of the panel. I took the time to snap a picture of the back of the panel before I started. On the top, you can see the small red, orange, and yellow DC wires for the backlight for the voltmeter. On the bottom, you can see the red and yellow DC wires for the backlight for the panel itself.
Now let's look at those parts of the panel that are devoted to the AC wiring. On the left you see two built-in bus bars. The one on the far left is where I would put the green wires, i.e., grounding wires. The next one is where I would put the white wires, i.e., the neutral wires. On the far right, you see the backs of the three breakers, each labeled 15A, in other words 15 amps. It was here that I would put the black wires, i.e., the hot wires. Notice that above the three 15 amp breakers there is one labeled 30A. This is the main breaker. It was here that I would put the black and the white wire from the shore power inlet. Throughout the wiring of this panel, I would refer to the printed instructions and the diagram that were included in the packaging from Blue Sea Systems. Saying what I'm about to say should be unnecessary, but if you attempt to wire this same type of panel, you should consider those official printed instructions as the authority, not my brief overview of my own approach.
In the picture below, we see a close-up of the back of the voltmeter. You'll notice the label indicates that the red wire is for 12 volt DC systems, whereas the orange one is for 24 volt systems. Since my system is 12 volt, I used the red, and I rolled up and taped off (with black electrical tape) the unneeded orange wire.
In my preparation for joining the wires to the back of the AC panel, I fed them into the appropriate hole in the bottom of the plastic protective cover. It was then that I realized I had made an error in the cutting of the hole in this protective cover. The problem was that I had drilled an isolated hole - one that had no access from any side. This lack of access would prevent me from installing the protective cover on the back of the panel after I had completed the wiring of the panel. What I needed was a cut-out or notch of some sort that would allow easy access to the hole.
The picture below should give you some idea of how difficult it was to access the back of the panel from the cockpit. What I needed to do was to remove the protective cover and pull all the wires through the bulkhead and into the galley. That way I could wire the panel in a somewhat easier manner.
Before I did this, however, I notched the protective cover with the Dremel. I was concerned that this might weaken the overall structure of the cover, but surprisingly it did little harm. The cover as a whole remained quite rigid. The screws that I would later use to mount this cover also helped to maintain the shape and rigidity of this molded structure.
Next, I notched the two holes on the side of the cover - the holes for the DC powered backlights for the voltmeter and the panel.
Afterwards, I placed the protective cover on top of the panel to see how much clearance the AC three-wire cables would have. I thought there might not be enough clearance, but I would later find out that there was.
In the comfort of the cockpit, I crimped some heat-shrink butt connectors onto the ends of the wires for the DC backlights. These butt connectors would allow me to join these DC wires to the ones that I had already routed to this part of the boat for this purpose.
Almost all of the wire and heat-shrink terminals for this complete rewiring of Oystercatcher I had purchased from Genuinedealz / BestBoatWire in Brunswick, Georgia, USA. Occasionally, I would run out of terminals and I would break down and go buy some ridiculously overpriced Ancor brand terminals from the local West Marine (which overprices almost everything to begin with). Here you see me using butt connectors designed for gauges 22 to 18. That's why the package is labeled 22 -18 AWG (American Wire Gauge). Connectors and terminals in the 22-18 range are colored pink to distinguish them from the 16-14 AWG fittings, which are blue, and the 12-10 AWG fittings, which are yellow.
After a quick blast from the heat gun, these heat-shrink terminals were ready to go.
Despite the fact that a 22-18 terminal is designed for 22-18 AWG wire, it can, in my experience, handle 16 AWG wire. On the left is the red wire from the voltmeter backlight. If I remember correctly, this was 22 AWG wire. On the right is the 16 AWG wire - the one that would run to the DC distribution panel. Waytek, Inc. in Minneapolis, Minnesota, USA makes some excellent adhesive lined step-down butt terminals 22-18 to 16-14. I had ordered about 30 of these from Waytek, and I had used all of them for wiring various LED lights and electronics in the boat. If I had had any more of these Waytek brand step-downs, I would have used them for this application. The 22-18, however, seemed to work just fine.
One last thing I did before I started the wiring was to take a couple of more pictures of the back of the panel. One of the stickers said that this was a World Circuit Breaker, "Certified for North American and European Markets."
The other sticker indicated that the breakers were a product of Carling Technologies. Having a photographic record of the printed specifications, I thought, would be helpful in the future.
Having temporarily reinstalled the AC distribution panel, I removed it once again for this wiring job.
Over the hole where the stove would eventually sit, I created a work table of sorts for myself with a couple of scrap pieces of plywood. I laid the panel on top of an old bubble-wrap mailing envelop to protect it. I also laid out the instructions that were included in the Blue Sea Systems packaging. Of these instructions I devoted most of my attention to the wiring diagram. I'll say this one more time, just in case you missed it . . . if you choose to wire the same type of panel on your own, do as I did and refer to the Blue Sea Systems instructions and diagram. As is almost always the case with these articles that I write on this website, my primary goal for providing these detailed descriptions and pictures is to remind myself how I approached some problem.
I wanted to proceed in the most logical fashion possible. Therefore, I began with the wires from the shore power inlet.
In the close-up below, you'll see that I have joined the green wire to the first screw on the grounding bus. You'll also see that I have joined the white and black wires to the main breaker. I have indicated each of these wires with an orange circle.
Next, I joined the circuit 1 wires. The green wire went to the grounding bus; the white wire went to the neutral bus; and the black wire went to the breaker for circuit 1. These three wires I have indicated with orange circles.
I took the picture below moments later from a different angle. Same stage of the wiring process.
For circuits 2 and 3, I had to get a little creative. You'll recall that I did not leave myself a service loop when wiring these two circuits. The reason? I didn't want a bunch of excess AC three-wire cable in the cockpit locker (where it could get damaged by tools or other items). In order to give myself enough slack to complete the wiring of the panel, I had to climb down into the lazarette and disconnect some of the cable hangers that I had earlier installed to restrain the gray plastic conduit through which the cables for circuits 2 and 3 ran.
With this slack, I was able to pull the gray conduit up into the cockpit locker and through the cut-out for the AC panel.
In the picture below, we see the wires for circuits 2 and 3 ready for installation.
The tangle of wires was getting thicker. Despite its appearance, however, it all made sense.
Having finished joining all of the AC wires to the panel, my next task was to install crimpable in-line fuse holders in the DC positive wires for the voltmeter and panel backlights. I used Blue Sea Systems brand fuse holders, PN 5060.
These were easy to install - one crimp on each of the two ends.
As always, I labeled each positive wire, so that I would easily know the purpose for each.
The last thing that I did was to join the AC grounding cable to the post at the bottom of the grounding bus on the bottom of the panel. This 6 AWG cable would run from here all the way to the bronze grounding bolt in the bilge.
Due to its size and its proximity to the bulkhead, this cable was not easy to join to the panel. It didn't help that there were lots of other wires in the way. This picture is not an exaggeration; I had to get my face this close (and closer) to see the work area.
Once I had joined all of the wires to the panel, it was time to install it in the cut-out. Immediately upon pushing the panel into place, I noticed resistance in the bottom right corner. I wrestled around with the wires a little bit and then tried it again, and again. Eventually, I figured out that I could not fully install the panel due to an obstruction in the area of the green grounding cable. The problem was that the bulkhead was too thick, and the green grounding cable, being the size that it was, and being terminated with a heavy duty lug, would not bend enough to make it past this obstruction. To remedy the problem, I pulled out my Rockwell Sonicrafter oscillating tool and installed a cutting blade. With this in hand, I carefully cut out a piece of plywood from the bulkhead.
Here's a close-up of what I'm talking about. I have placed the small piece of plywood back into place (but at an angle, for emphasis) for the sake of this photograph.
Here's the way it looked with the plywood fully removed. This did the trick.
Now I was able to install the AC panel fully into place.
That was the easy part. Now I needed to clean up the mess behind the panel.
I began by taping all the AC three-wire cables together with black electrical tape. This would help me fit them into the hole in the protective cover. Next, I used duct tape to pull all of the DC wiring out of the way. What made these tasks challenging was that I had to do almost all of this with one hand, since it was on the far side of the cockpit locker.
With the wires taped and organized in this fashion, the initial installation of the protective cover was not that difficult. Fortunately, all the cut-outs were just the right size. The final installation, which required the installation of screws in the bulkhead was more difficult. I drilled pilot holes with one hand. Afterwards, I installed the screws with one hand, using a screwdriver with a magnetic bit holder.
My final two tasks involved the conduits. First, I joined the positive DC wires together in a black, plastic split-loom conduit, and then I taped this conduit to the side of the protective cover with white Gorilla brand tape. This type of duct tape is very strong and durable. It would hold the conduit firmly in place, but it would also allow me to remove the conduit from the side of the cover and pull it toward me in the cockpit. This would allow me to change the fuses in the in-line fuse holders when necessary. Secondly, I trimmed the gray, plastic, split-loom conduit on the three-wire cables, and I added an additional gray conduit to the other cables on the outboard side of the protective cover. This conduit work I did not photograph.
The installation of this AC distribution panel was time-consuming, and it required a lot of thought, but in the end I was glad that I had undertaken this project. Having AC power would allow me to use this boat in many ways that DC power would not.

This ends this article on how I installed the AC distribution panel in Oystercatcher, my Ericson 25.


  1. Roscoe, your blog on the Ericson 25 is the best online hands down. Just had to say it. I'm looking at rewiring my electric which is pretty hodge podge, and your blog is inspiring, so thanks!

    1. Hey thanks Leif. Glad that you are benefiting from these articles. I have more electrical articles to come . . . eventually.