Electrical, DC Branch Circuits 1.1 - 1.3: Mast Wiring (Interior of Boat)

Terminal block with interior mast wires in place, ready for the exterior mast wires to be joined
If you've read my previous postings on my wiring of my DC distribution panels in Oystercatcher, my Ericson 25, then you'll recall that I chose to install three separate panels in the galley area of the boat. Likewise, you'll recall that I decided to devote the first of these panels (the one aft of the other two) to the lights and electronics associated with the navigation of the vessel.

In the present posting I describe my wiring of circuits 1, 2, and 3, those circuits that I would be dedicating to the anchor light, the steaming light, and the foredeck light respectively. These, of course, are circuits concerned with the lights located on the mast of the boat. I will address the mast lights and wires themselves in another posting. In this posting I will focus exclusively on the wiring of the circuits on the interior of the boat.
In my rewiring of these circuits, I routed the new wires along a path almost identical to the path that the original wires had followed. From the forward locker underneath the settee berth the wires would run underneath the main salon sole to the mast compression post and bulkhead. I would not route these wires up through the center of the mast compression post as the original wires had been routed. Instead, I would route them up the bulkhead inside of the head (as pictured above).
In the picture below we see the three panels of the DC electrical system. I would be dedicating the aft panel (far left) to everything associated with the navigation of the vessel.
I routed all branch circuit wires from these three panels to terminal blocks in the port side alcove box of the main salon.
I used gray wires for Panel 1 (Navigation), blue wires for Panel 2 (Lights, Interior), and orange wires for Panel 3 (Miscellaneous - service lights, etc.). The yellow wire was for the negative circuit for all three panels and their branch circuits.

If you click on the picture below, you can see the labels. Circuits 1, 2, and 3 have wires that are labeled, "Anchor," "Steam," and "Foredeck." Circuit 4 has three wires labeled, "Stern," "Compass," and "Bow." These wires are for the navigation lights on the bow and the stern. I included the compass light in the circuit, because clearly I would want the compass light on whenever the nav lights were on. Circuit 5 has a single wire labeled, "Cockpit." This is for the DC receptacle that I would install in the cockpit for the cockpit anchor light. When anchoring I would usually use both the masthead anchor light and the cockpit anchor light so that other boaters would not mistake the masthead anchor light for a distant star. There is not a sixth circuit wire on this terminal block, because I dedicated the sixth circuit to a navigation sub-panel, which I had placed in the cockpit locker of the boat. This sub-panel controlled the VHF radio, the GPS, and the handheld VHF.
In the pictures above and below I've not yet run the leads that would connect DC Panel 1 to this terminal block. This aside, note that the anchor, steam, and foredeck wires are routed forward.
From this terminal block, I routed these wires forward to the alcove box behind the hanging locker. Now lets go back in time to see how did this.
In this alcove box I had installed a bus bar for the DC negative circuit. These positive wires, obviously did not belong there. Pay attention instead to the hole to which I am pointing. This is where Ericson workers had routed the original wires for the mast lights.
From this hole, Ericson had routed the wires through the interior of the hanging locker.
Then they had routed the wires through a hole in the bottom of the bulkhead. This hole led to the locker beneath the settee berth.
From there, they had routed the wires underneath the sole of the main salon. Then they had routed them up the hollow mast compression post. In the picture below I have removed two of the mahogany boards that make up the mast compression post.
I would route the new wires along a similar path. After making careful measurements, I rolled out spools of wire to the appropriate length on my front porch and made the cuts.
Since the three positive wires were all gray in color, I labeled each one with a temporary tag.
I did not neglect to mark the opposite end of each wire. To not have done so would have been a stupid mistake.
I then installed split loom conduit around the four wires. This would protect them from chafing. The split would allow air to circulate more easily and it would allow moisture to escape.
By the time I performed these tasks I had painted the hanging locker a brilliant white. I used Pitthane, a commercial grade, two-part polyurethane - the same paint I had used in the lazarette and elsewhere. Notice the second hole in the picture below. That is for the grounding wire that I would route from the chainplate to the grounding bolt in the bilge adjacent to the mast compression post.
I began my routing of these wires (within their split loom conduit), but pushing them up through the hole in the hanging locker.

This enabled me to get a good sense of how much wire I needed in the alcove box.
I then concentrated on routing the wires through the hole in the bulkhead. I had to remove some of the split loom conduit to fit them through the hole. After I worked them through the hole, I worked the conduit itself through the hole. The second hole you see below is for the chainplate grounding wire.
Prior to routing these wires, I had enlarged the original holes in the settee locker.
There were two small holes on the hanging locker side of the bulkhead. These led to one large hole on the other side of the bulkhead. How was this possible, you ask? Because the holes - at least those holes that were visible - were not through the bulkhead itself but through the fiberglass tabbing that held the bulkhead to the hull. Through this one large hole would pass these mast wires and the chainplate grounding wire. Then these mast wires and the single chainplate wire would pass through their own holes (circled in red) to the space beneath the main salon sole.


In the picture below we see the bilge adjacent to the mast compression post. I would eventually route the chainplate wire to the grounding bolt pictured bottom left. To the right, you can see the group of mast wires that I have just routed into this space beneath the sole.
I stuck my camera down into the bilge and captured this image. The space is cramped because of the 2,500 pounds of lead that are encapsulated in the hull.
I taped the new wires to the original wires and pulled them up through the narrow space between the hull liner and the centerboard trunk.

Before going any farther, I went back to the terminal block in the main salon alcove box and joined all the positive wires to the terminal block with ring terminals. Then I pulled the slack out of the wires and began to install conduit hangers in the hanging locker.
These hangers secured the conduit and kept things organized.

Fortunately, I was able to fit the conduit through the narrow gap between the hull liner and the centerboard trunk.
Next, I installed a terminal block on the bulkhead inside the head. Eventually, I would drill a hole through the cabin top just above this terminal block and install a white, plastic through hull. It's through this hole that I would eventually route the wires down from the mast to this terminal block.
I had to use two different pieces of conduit to complete this job. I joined them with electrical tape.
I test fit one of the pieces of mahogany for the mast compression post. Fortunately, there was just enough room for the wires and conduit in the narrow space between the mahogany and the centerboard cable shaft. Ericson had originally routed the wires directly up to the top of the mast compression post. From here, Ericson had routed them through a hole in the aluminum mast step, a hole that of course led to the inner cavity of the mast. Here is where my routing of the wires would differ. I would route them through a hole in the bulkhead into the head.

There was a pre-existing hole in the bulkhead at just the right spot. Actually, there was rot in this area that I dug out to create this hole. The rot was there because water had for years seeped down the wires in the mast and the mast compression post. I would patch this hole with a piece of red oak
I used a large terminal block so there would be room for growth. Eventually, I would add spreader lights. I would join the positive wires of these spreader lights to the foredeck wire circuit. This meant that eventually I would dedicate the lower half of the terminal block to the five negative wires that would descend from the mast wiring - the negative wires for the anchor light, the steaming light, the foredeck light, and the two spreader lights.
At this time, I also routed some orange wires from DC Panel 3 through the hanging locker.
These wires were for the small LED lights that I would eventually add to this locker and the V-berth lockers.
I took the time to label these conduits so that it would be easier for me to troubleshoot any problems I might encounter in the future.


This ends this posting on my routing of the wires for the mast lights on the interior of Oystercatcher, my Ericson 25.