Electrical, DC Main Circuit Breaker, Part 2: Wiring

The protective cover for the DC main circuit breaker

The wiring of a DC main circuit breaker would seem to be one of the easier tasks in the complete rewiring of a sailboat. After all, there are only two wires that join it. Things, though, in boat work, never are as easy as they seem. There are unexpected problems that create unexpected delays, and before you know it, what seemed at first as if it would require only a hour's worth of work ends up requiring much of the day. Replacing an existing component of an existing electrical system is not difficult. Creating an entirely new system is not. How much wire will I need? Where will I route it? Where will I terminate it? What size terminals do I need? Will this wire obstruct another that I will need to run through the same area tomorrow or the next day? How much chafe protection do I need? Is it the right size for the wire that I need to create for this component? For that matter, is the wire itself the right size for the job? Will it overheat? Have I taken into account the length of the run and the voltage drop? Wait a second, if I move up to a heavier gauge wire, then I'll need to order additional terminals, and maybe additional conduit, and maybe now the other wires that I planned to run through this area won't fit. These and many other similar questions I asked myself time and time again in the planning and execution of this complete rewiring of Oystercatcher my Ericson 25.

In this posting, the second of two in my article on the DC main circuit breaker, I describe the steps I took and the problems I solved to install two simple wires.

Let's start by looking at the protective cover for the DC breaker. You'll notice that there are two wires exiting it. The one on top is labeled "TO DC PANEL." The one on the right, that is fully sheathed, runs to the battery switch.

Now let's look on the other side of the bulkhead where things are nice and pretty. This was the way it looked after I had temporarily installed all of these components.The red switch is the battery switch. To right of it is the battery monitor, and to the right of the battery monitor is the DC breaker.

What I needed to do was to route a wire from the back of the battery switch (the red thing on the right) to the back of the DC breaker (the black thing on the left). It was clear from the start that I would have to route this wire around the back of the battery monitor (the round white thing in the middle). It was also clear that the blue protective cover that I had planned to install over the back of the battery monitor was no longer an option. It had to go.

What was not clear from the start, however, was that the thickness of the bulkhead would prevent me from connecting the wire from the battery switch to the back of the DC breaker.

Having made the wire and labeled it (tasks that I will not here describe, since I have described similar tasks in detail elsewhere in other articles) I now needed to figure out how to remove some of the plywood from the bulkhead in the area around the back of the DC breaker. You'll recall that I installed the DC breaker in the large hole where the old battery switch used to be. I was fortunate to have done this, because the extra space of this old hole gave me a little more working room.

Using my Dremel, with a sanding drum attached, I slowly routed out pathways of sorts for the two wires, being very cautious not to nick any of the wires in the vicinity. This tool can do a lot of damage in short period of time, if you're not careful. I should note that I did all of this work on my knees, while leaning into the cockpit locker.

I also had to be cautious about sanding too deeply. Otherwise, I would create not a rut, but a hole - a hole clean through the bulkhead. Note that I have covered the back of the battery monitor with duct tape to prevent dust from damaging the instrument.

Once I had routed out these pathways to a sufficient depth, I temporarily installed the two wires on the back of the DC breaker. I continue to use the word wire, but since this wire is 6 AWG (American Wire Gauge), it is normally classified as a cable.

At any rate, the wire that I routed upward from the back of the DC breaker led to the DC distribution panels in the galley. To get there, I routed the wire up and over the blue protective cover for the back of the bilge pump switches. Then I routed it through a small opening between the bulkhead and the hull. This wire, sheathed in a black, split-loom conduit, is near the gray plastic conduit on the far left. You just can't see it in this picture. Note that I used the white AC three-wire cable to hold the wire in place.

Below is a picture of the galley. To the left you can see the various white labeled conduits that I have routed through the small opening between the bulkhead and the hull. To right you can see a Blue Sea Systems terminal stud. It was to this stud that I would connect the wire from the DC breaker. The gray, blue, and orange wires are for the DC branch circuits. I address these in separate articles.

Here's the terminal stud after I have connected the 6 AWG wire to it. The other wires, which are 10 AWG, feed the three DC distribution panels. Connecting these three wires to the panels was one of the last things that I did in this complete rewiring of the boat. By this point, the only 10 AWG wire that I had left was yellow, the color I used elsewhere to indicate negative. Not wanting to order another spool of 10 AWG for such a small amount of wire, I decided to use the yellow 10 AWG but to color-code it with red tape and to label it with a + sign to make it clear that it was positive.

Before going any further I needed to seal the joint between the bulkhead and the hull liner in the galley. To do this, I used NP1, a polyurethane adhesive/sealant not unlike 3M 4200 or Sikaflex. NP1 is available in good hardware stores and, since it's sold as a construction material and not a "marine" material, it's much less expensive. It comes in a variety of colors. I selected Off White to match the interior of the boat.

There was a small gap in the joint. I wanted to seal this, so that air would not freely move between the interior of the boat and the cockpit. The NP1 worked well, and the Off White color blended perfectly with the color of the gelcoat on the interior of the boat.

The next issue I faced concerned the final installation of the breaker itself. Up until this point the breaker was only loosely seated in its housing with short screws. Now I needed to mount it with fasteners of sufficient length to prevent it from working itself free. I did not have fasteners of sufficient length, so I had to make a trip to the hardware store. Fortunately, here in Charleston, South Carolina, there are still some traditional hardware stores that sell individual stainless steel fasteners from open bins rather than prepackaged fasteners in quantities that you often do not need.

The fasteners had to be long enough to penetrate the first or second layer of the bulkhead, but not too long that they would pass all the way through these layers.

The DC breaker as it appeared shortly after I had screwed it fully into position.

One problem that I ran into, in terms of the fasteners was that, in the area above the back of the breaker, there was no bulkhead into which I could screw a fastener. The only material that the fastener could grab was the mahogany of the decorative backer. This was not necessarily a problem in and of itself. The problem, rather, was that the end of the fastener penetrated the mahogany and projected into the space where the wire for the DC panel needed to run. To remedy this problem, I pulled out the Dremel and sanded away the end of the fastener. By the time I finished, all that was left was a small stainless steel nub that was barely detectable when touched by a fingertip.

Despite the smoothness and the almost non-existence of this nub, I still thought it would be wise to cover it with several layers of black electrical tape. This was insurance of sorts against the possibility of chafing action.

Next, I needed to focus more closely on the wire that ran from the battery switch to the breaker. Up until this point it was just loosely connected to these two components.

One reason I kept it loose was because I still needed to connect the 1 AWG wires to the back of the battery switch. I had to be sure that this 6 AWG wire would fit with all of these larger wires in this space.

Fortunately, it looked like it would, so I screwed the protective cover into place over the back of the battery switch.

Now I was able to focus on tightening the nuts on the back of the DC breaker and finding a protective cover for it.

Here I encountered another obstacle. When I had earlier hand tightened the lock nuts on these studs on the back of the breaker, everything seemed okay. Now, using a ratchet wrench, I could not get a good grip on these nuts. Therefore, I experimented with different nuts in my miscellaneous bag of stainless steel hardware. A number 10 nut was too small, and a 1/4 inch nut was too large. Puzzled, I made a trip to the hardware store. There, I discovered that the nut I needed was in fact a metric sized nut. Fortunately, this hardware store keeps stainless steel metric fasteners in stock. Back at the boat, I tightened these metric nuts into place using a metric ratchet - a tool that I rarely use, but one that I am glad that I had. I'm still not sure why Blue Sea Systems opted for the metric system on this breaker when they use the English system on all their other components that I have encountered. While I'm at it, I should note that I was able to solve this metric puzzle by taking the original nuts to the hardware store. Yes, this breaker came with nuts. I needed a second set of nuts, because I used the first set as stand-offs. In other words, I installed them behind the lugs. This helped me in the seating of these lugs in this tight space.

Now that I had solved the nut problem, I needed to solve another. As I contemplated how I might protect the back of the DC breaker, I slowly began to remember a conversation that I had had with the tech person at Blue Sea Systems and the notes I had taken at that time. I had asked this tech person if I needed to fuse the wire that would run between the battery switch and the DC breaker. He said that, according to ABYC (American Boat and Yacht Council) standards, the battery switch is a power source. Therefore, he said, if the wire coming off it were to be over 7 inches in length, then it would need to be protected by a fuse. He added, however, that if this wire were to be protected by a sheath or conduit, then it could be up to 40 inches in length without being protected by a fuse. After consulting my notes, I pulled out my tape measure to check the length of the wire. Sure enough, it was an inch or two over the 7 inch limit. I knew that given the space restrictions a fuse was out of the question. Therefore, I decided on the quickest and easiest solution possible - sheathing the wire in a split-loom conduit.

This was something that I really should have done in the first place, given the twists and turns that this wire had to make in such a small space, and given the proximity of this wire to the wire that fed the DC distribution panels. As an added measure of protection I wrapped the end of the conduit many times with black electrical tape to insulate this wire from the adjacent one on the back of the breaker.

In terms of protecting the back of the breaker itself, I experimented with several options until I settled on the one you see pictured below. Yes, this is an electrical box for an AC receptacle. Specifically, it is known as a "shallow work" box, due to its slim profile. It fit perfectly in this space, and it left plenty of room for the two wires to enter and exit the box.

At this point, my complete rewiring of the boat was almost at its end. This is the way the cockpit locker appeared at this time.

Despite the fact that it was obvious to me at this moment that this was the main DC breaker, I still went ahead and labeled the box. This would provide immediate recognition and clarity for me or for anyone else (who might be assisting me) at any point in the future.

Yes, this was a lot of work for two simple wires, but then again I could tell countless stories of similar tasks in the refitting of this boat that seemed at first to be simple, but ended up being much more time consuming than I had ever imagined.

This ends this posting on how I wired the DC main circuit breaker on Oystercatcher, my Ericson 25.

Electrical, AC Receptacle, Galley, Port Side, Part 2: Wiring

The AC receptacle, fully wired and installed

Choosing the place where I would install the AC receptacle and then installing it (at least temporarily) were projects in and of themselves, and it was for these reasons that I devoted the first part of this two-part article to them. In this second part, I discuss the process of wiring this receptacle. I use the word process here not without deliberation. Since I was not simply replacing the existing wire for an existing receptacle or simply replacing an existing receptacle itself, I first had to determine how to route the wires. Then I had to determine how I would join them to this entirely new receptacle in such a confined space. How I did all of this on Oystercatcher, my Ericson 25, is the subject of this posting.

 

You'll recall that it was on the port side of the galley that I had also temporarily installed most of the other major components of the AC and DC electrical systems - the battery switch, the battery monitor, the main DC breaker, the AC distribution panel, the two bilge switches, and the three DC distribution panels.

The most challenging task was trying to determine how to fit all of these components into this space and, at the same time, trying to imagine how the wiring, that would go behind them, would fit into that space behind them.

Compounding these challenges was the space itself behind these components. This was a cockpit locker. The space was small; it was not easy to access; and, despite whatever I might need to do from an electrical standpoint, it still needed to be used for its intended purpose - stowing gear.

In terms of the wiring itself, I needed to figure out how to route the wires from the AC distribution panel on the far left to the AC receptacle on the far right.

A simple, straight shot would not do. For one thing, I had to route the wires through the protective covers, which would require me to make right angles. For another, I had to take into account all the other wires that I would need to route through this area.

Everything also needed to fit behind the protective cover that I was in the process of creating for this space.

Additionally, I had to take into account the wiring that would be passing from the cockpit locker into the lazarette, directly beneath it.

All of this was so complex that it was difficult to know where to begin. I had to start somewhere, and one of the first things I did was to route the wires for the AC receptacles that would be on the starboard side of the boat. These I placed in a gray, plastic conduit to help prevent chafing. At the same time, I routed the 6 AWG (American Wire Gauge) grounding cable for the AC system. This I put inside of a small, black, plastic conduit. In the picture below, you can see this black conduit coming down from the cockpit locker with the gray one.

Note that I am now using the word cable as opposed to the word wire in speaking of the AC system. I'm doing this because many people use the word cable to refer to large wire. 6 AWG wire, or I should say cable, falls into this category. Likewise, many people, including manufacturers, refer to bundled marine wire as "boat cable." The wire that I selected for the AC system was bundled or sheathed in a white, plastic, protective cover.

Up in the cockpit locker I left enough slack in these cables so that I could terminate them and join them to the AC distribution panel. Ideally, I would have left more slack in the cables, but I didn't want to have too much of it left over at the end of the project, especially in a cockpit locker. Pay no attention to the wires on the far left. These were some of the remnants of the old wiring. I had already removed almost all of it. Some of it I left here and there, just to remind me of some of the major routes of the old system.

After I had routed the above mentioned AC cables (in other words, the ones that passed through the lazarette), I thought it would be smart to go ahead and route some of the wires and cables for the DC system before I routed the AC cable that is the subject of this posting - the AC cable that would join the AC distribution panel to the AC receptacle, pictured right in the photograph below. As I said before, I had to take all of these other wires and cables into account. Otherwise, I would never be able to fit all of these pieces of the puzzle together.

When the time at last came for me to route this cable, I began by cutting a hole in the top of the electrical box. In the world of residential construction, the box you see pictured below is known as a "shallow" box. It is intended for tight spaces, and this space in this cockpit locker was, without a doubt, tight. The standard, punch-out hole in this box was not the right shape or size. Therefore, I used my Dremel to cut a rectangular-shaped oval hole that was just the right size for the boat cable that needed to pass through it. After I fed the cable through the box, I carefully stripped the white, protective cover back to reveal the three 10 AWG wires within. One was black, one was white, and the other was green.

Some might say that 10 AWG wire is too big, but not me. After all, I was dedicating this receptacle to the window unit style air conditioner that I would mount in the companionway when the weather was hot and humid. These appliances draw a lot of power, and I wanted to minimize resistance and voltage drop. Besides, I had to buy 10 AWG wire for the shore power inlet. Likewise, I needed to buy 10 AWG wire for the AC receptacle on the starboard side of the galley, which was dedicated to the battery charger, and which would draw 11 amps while charging.

Inside the boat, I joined the green wire, which is the ground wire, to the screw terminal with a forked heat-shrink terminal that I had earlier installed on the end of the wire.

As far as the black wire (hot) and the white wire (neutral) were concerned, I joined these to the receptacle in the style commonly seen in residential wiring jobs. Instead of crimping and heat-shrinking terminals on the ends of the wires, I simply stripped the wires to the proper length, inserted them into the appropriate holes, and tightened down the appropriate screws. Why did I do it this way? Well, from what I could tell, it appeared that there was just no way that I could fit the receptacle into the shallow box if I used heat-shrink terminals on the ends of these wires. Using a heat-shrink terminal on the green wire would work, since the screw terminal for this green wire was more recessessed than the ones for the black and white wires. This seemed like a really bad decision on my part, but I did not see any way around it at the time.

Having joined the three wires to the AC receptacle, I had a buddy stand in the boat and hold the receptacle steady while I slowly worked the cable through the box. The goal, of course, was to fasten the box to the bulkhead where it belonged.

After I had secured the box in its proper place, I began to think about how I might route the cable. Having installed the cable on the top side of the box, I already knew that I needed to route it upward and across rather than downward and across.

To protect the back of the bilge switches, I had installed a modified old work box, pictured below in blue. Over this I had already routed the red positive cable from the back of the main DC breaker. This seemed like a good route for the AC cable as well.

As I routed the AC cable, I left room for the black conduit that I soon afterwards routed downward from the bilge pump switches. The gray conduit that I had earlier routed upward, over the bulkhead was for the yellow negative 10 AWG wires for the DC distribution panels in the galley.

At this point I considered this part of the overall AC wiring project complete. Several weeks later, however, I returned to this circuit to have a second look at the receptacle. Ever since I had installed it, I had been concerned about my decision not to install heat-shrink terminals on the black and white wires. Therefore, I thought it would be a good to return to this receptacle and reevaluate the situation.

My greatest concern, of course, was that these wires would soon corrode in the warm, salty air of Charleston, South Carolina. The space in this shallow work box was indeed very tight, but I thought I might be able to make this receptacle fit with heat-shrink terminals on the black and white wires. The issue with heat-shrinks, as you can see on the green wire below, is that they inhibit the bending of the wire.

My first thought was that I could help matters by cutting off half of the heat-shrink material. After dry-fitting the one pictured below on one of the wires, however, I changed my mind. I wanted these wires to be as protected as possible.

It was not easy crimping these terminals on the wires.

There was no extra wire, so I had to do this work right up next to the bulkhead.

Even more challenging was the heat shrinking of the terminals. I had to set up a temporary shield of plain mahogany to protect the varnish on the finished mahogany panel behind the battery switch. I also had to use needle nose pliers to turn the terminals as I applied the heat. If I had not done this, I would not have shrunk the terminals correctly.

The work area got so hot that the blue electrical box became soft and pliable. After I had finished the job, I took this picture of the box, as seen from the cockpit locker. Notice how the right hand side is slightly concave. Fortunately, the black plastic conduits beside it were unaffected.

The Pass & Seymour brand GFCI that I used was more welcoming than other brands for the use of heat-shrink terminals. Some of them have plastic nubs near the screws which prevent you from inserting a forked terminal underneath the screw. Why not use ring terminals you might ask? Well, the screws are not designed to be removed from the receptacle. Having done some residential wiring, I knew this. Nevertheless, I thought it was worth trying to remove them, so that I could use ring terminals instead of forked terminals, since the former provide better contact than the latter. With a little force I was able to remove the first screw. Not a problem, or so I thought. Immediately afterwards, I reinstalled the screw and attempted to tighten it down. It would not cooperate. The reason? I had stripped the threads. The result? The GFCI was ruined. What did I have to do? Go out and buy another one. The lesson learned? Forked terminals are the way to go on AC receptacles. By the way, in case you're wondering, in my experience in installing the AC receptacles in Oystercatcher, I found that the screws on the receptacles, regardless of the two different brands that I used, were Number 8 in size.

The makers of these receptacles have done a lot to keep people from making dumb mistakes while wiring them. For instance, they have placed yellow tape over the screws on one end to warn people not to install wires on those screws if this GFCI is the only receptacle on the circuit. Likewise, they have labeled the screws according to the wires they are to receive.

After double-checking and then double-checking one more time, I installed the wires in their appropriate locations.

I felt much better now that all three of these wires were protected with heat-shrink terminals.

Fortunately, I had very little trouble fitting the receptacle into the box, even though the heat-shrink terminals made the fit even tighter than it already was.

At last I could install the stainless steel protective plate and call this part of the overall AC wiring project complete.

This ends this posting on how I wired the AC receptacle on the port side of the galley in Oystercatcher, my Ericson 25.