Electrical, Bilge Pump Switches, Part 2: Wiring

The bilge pump switches, wired and ready for final installation

Having discussed, in the first half of this article, my reasoning behind my choice of certain brands of bilge pump switches and bilge pumps, and having discussed my rationale for locating these switches and pumps where I located them, I will now discuss, in the second half of this article, the steps I took in the wiring of these devices in Oystercatcher, my Ericson 25.

Although these Blue Sea Systems bilge pump switches, like all bilge pump switches, are rather small, they require quite a bit of wiring, and, in my experience, quite a bit of time to wire. Certainly the stripping, the crimping, the heat-shrinking, and the labeling of each wire was time-consuming in and of itself. That, however, can be said for any wiring project on a boat. What I'm talking about here is the routing of all of these wires. The 16 AWG (American Wire Gauge) yellow wire had to go to a negative bus bar in the cockpit locker. This yellow wire was the negative for the LED. The two 14 AWG red wires had to go all the way to the bilge. These would serve the pump and its float switch. The 14 AWG red wire on the far right (in the picture above and below) had to go to the house bank bus bar in the lazarette. This red wire was, of course, the positive wire that fed this bilge pump switch.

Before I had ever started this wiring process, I had temporarily installed the bilge pump switches in the bulkhead in the galley of Oystercatcher.

The backside of the bulkhead was in the cockpit locker on the port side of the boat.

The bilge pump switches were the least accessible of all the electrical components in this space.

In the lazarette, just beneath the cockpit locker, there were bus bars for the DC main circuit. The outboard bus bar, i.e., the one on the far left, was dedicated to the house battery bank. It's to this bus bar that I would need to rout the positive wires for the two bilge pump switches. See the bus bar in the cockpit locker? It's to this that I would need to route the LED negatives. As far as the other wires were concerned, I would need to route them down into the lazarette, and from there, downward into the bilge. While this might seem simple, it was not. There were many other wires to route through these spaces, and I had to take many of them into consideration. As I have said in other articles, if I were simply replacing and rewiring an existing component of an existing electrical system, this would not have been that challenging. Since, however, I was creating this electrical system anew, I had to take many different things into consideration during almost every step of the process. At times I felt like I was playing several different games of chess at once.

Now let's focus on the positive wires themselves. In the picture below, we see the gray, 10 AWG wire for the emergency bilge pump switch. I used 10 AWG on this switch due to the size of the emergency pump and its energy demands. The female quick disconnect that I crimped and heat shrunk on the end of the wire was almost too large for the male blade on the back of the switch. I had to bend the blade down slightly to get enough clearance from the switch fuse, which was an obstruction of sorts. I used black electrical tape to support this 10 AWG wire and to keep it from bending the blade any more than necessary.

I have already discussed the wiring of the primarily bilge pump switch, i.e., the switch we see pictured below. I'll only add here that the red 14 AWG wire (on the far right) was much easier to slide onto the male blade. It was almost as if the switch had been designed with 14 AWG wire in mind. I found this surprising, especially since the clear and well-written instructional information that came with the switch from Blue Sea Systems indicated that 10 AWG wire is often necessary in the wiring of bilge pumps.

In order to route these two positive wires downward into the lazarette I had to drill a hole in the bottom of the cockpit locker.

I had already drilled a large hole for the gray conduit that held two AC three-wire cables. I had also drilled a hole for the black conduit that held the 6 AWG grounding cable for the AC distribution panel. Now I drilled another hole for the these two positive wires from the bilge pump switches. I planned to use this same hole (and the black conduit that I would run through it) for the pump and float switch wires, which also had to be routed down into the lazarette. The second hole that you see pictured, therefore, has nothing to do with the bilge pump switches. This one would be dedicated to the battery monitor data cable. I knew that I also had to route this cable downward into the lazarette, so I went ahead and drilled it at this time, before things got too crazy with wires running everywhere.

When drilling these holes, I made sure to drill them through the un-cored area of the locker. Notice the large cut-out for the hatch that I would later install in the cockpit locker. I had earlier routed out the balsa core about 1/8 inch and had filled the gap with thickened epoxy. I did this, of course, to prevent moisture from working its way into the core and causing rot. By drilling through the un-cored area, close to the bulkhead, I was able to leave the balsa core undisturbed.

I said that things would get crazy with the wires. The picture below gives you a glimpse of this.

Now let's focus again on those positive wires from the bilge pump switches. You can see that I have now connected them to the house bus bar. This bus bar would in turn be connected directly to the house battery bank by a 1 AWG cable. It is standard practice, of course, to connect the bilge pump switches to the house bank, instead of connecting them to a DC distribution panel. This direct link to the battery bank ensures that the bilge pumps are always ready for action . . . assuming, of course, that the house battery bank is itself alive and ready for action, or at least has enough of a charge to support both pumps working non-stop for an extended period of time. On the Ericson Forum, some time ago, I floated the idea of wiring one of the bilge pumps to the house bank and one to the reserve bank, just in case one of the batteries failed. Maine Sail, whose advice I do not take lightly, urged me to stick with the standard practice of wiring both bilge pumps to the house bank. For this reason, I stuck with the status quo. I do still wonder, however, if there might be some value in distributing the bilge pumps in the fashion I described.

It is difficult to see in the picture above, but there are three other wires in that black conduit aside from the two positive wires. Two of these three other wires are red, and one of them is gray. The two red wires are for the primary bilge pump switch. One is for the manual switching of the pump, and the other is for the pump's float switch. The gray wire is for the emergency bilge pump switch. The reason why there is only one gray wire and not two, is because the emergency bilge pump does not have a float switch. There is only the pump itself. Why did I not want a float switch on the emergency pump? Because this was an emergency pump - one that I, or someone else, would activate by hand (in other words by throwing the Blue Sea Systems switch in the galley) when necessary.

Seeing this picture of the back of the primary bilge pump switch might be helpful.

Likewise, it might be helpful to see this picture of the back of the emergency bilge pump switch. Notice how the blade for the float switch has no wire on it.

Before we leave the lazarette, let's take a look at the main negative bus bar. You'll see a black wire and a yellow wire connected to it. The black wire is the negative for the primary pump. The yellow wire is the negative for the emergency pump. These negatives are different, of course, from the negatives that I earlier discussed. Those were the LED negatives for the switches. These are the negatives for the pumps themselves.

Now let's go to the bilge. During the planning stages of this complete rewiring of Oystercatcher, I had slowly purchased the various components that would be necessary for this major project. Two of these components were the bilge pumps. Knowing the physical dimensions of these pumps was a big help. It enabled me to construct, in advance of the rewiring project, a shelf for the emergency bilge pump. This shelf would keep the emergency bilge pump high and dry, while allowing the primary bilge pump, which would reside underneath it, to do the regular, day to day work. For more on all of this, see my article, "Plumbing, Bilge Pumps, Electrical."

In terms of the installation of the emergency bilge pump, I began by screwing the base of the pump into the shelf.

This was a Rule brand 2000 GPH (Gallon Per Hour) pump. The installation of this pump was a snap. Pardon the pun, but yes, all I had to do after I had installed the base was snap the pump itself into place.

Next, I grabbed the primary bilge pump - a Whale brand Supersub Smart 650. I removed the filter screen assembly from the pump itself to remind myself of how it would fit underneath the shelf.

The hole in the shelf was intended for the hose that would join the bilge pump.

While I had the Supersub 650 broken into two pieces, I thought it would be a good idea, for the sake of future reference, to take a picture of the impeller.

The Whale brand pump came with long leads. One was black, another white, and the third, brown. The leads were long enough for me to route them through the bilge (underneath the cabin sole) and into the lazarette. In the lazarette, I joined the white and the brown wires to the two red wires that I had previously routed downward into the lazarette from the primary bilge pump switch in the galley. The white wire was for the manual operation of the pump. The brown wire was for the automatic float switch. I joined these wires using adhesive lined heat shrink butt connectors. As far as the black wire was concerned, after terminating it with an adhesive lined heat shrink ring terminal, I routed it directly to the main negative bus bar on the backplane of the lazarette. I just described this wire and that bus bar in one of the recent pictures above.

As far as the emergency bilge pump was concerned, the leads on it were not long enough for me to route them all the way out of the bilge. Therefore, I decided to use a terminal block to join the necessary wires.

Whereas the brown wire for the Whale brand pump was for the automatic float switch, the brown wire for this Rule brand pump was for the manual operation of the pump. As I said earlier, this Rule brand pump did not have an automatic float switch. At any rate, in the picture below, you'll see that, after terminating the wire with an adhesive lined heat shrink ring terminal, I installed it in the far right position. Next to it, I installed the gray wire that I had previously routed downward from the emergency bilge pump switch in the galley. By installing a terminal jumper underneath the screws for these two wires, I essentially joined these two wires together. You'll also see two other wires. The black one is the negative from the pump. The yellow one is the one that I had routed down from the main negative bus bar on the backplane in the lazarette. I discussed this main negative bus bar and yellow wire above.

On both sides of bilge access there were small fiberglass tabs. It appears that Ericson had designed these tabs to be used as mounting blocks of sorts for wire hangers. To port we see three black conduits. One of them is for the transducer cable; another is for the AC grounding cable; and the third is for the main DC grounding cable. Later I would route two more grounding cables through here - one for each of the two backstays.

On the tab on the starboard side of the bilge access I mounted the terminal block.

Having completed the wiring of the switches and the pumps, I now needed to figure out how to protect the back side of the switches. The wires for these switches projected into the cockpit locker, and I didn't want any objects that might move around inside of the locker to damage them while the boat was under way.

Normal AC electrical boxes would not work for these switches. The boxes were wide enough, but not deep enough. At first, I thought I would use two separate one-gang AC electrical boxes, and that I would make room for the wires by cutting the backs out of the boxes. Eventually, I settled on a three-gang "old work" box, deciding that one large box would be easier to install than two separate ones. Also, I figured that one large box would provide better strength and protection.

Using my Dremel with my incredibly useful, fiberglass cutting bit attached, I quickly cut two holes in the back of this three-gang box.

Installing this box was not easy. A got a helper to reach through from the galley and hold the box against the bulkhead while I drilled four small pilot holes with my left hand. Then, using a magnetic tipped screwdriver, I installed the four screws. How many times did I drop the screws? I lost count.

The three-gang box appeared that it would provide good protection for the backs of these switches, so I was glad that I had invested the time and effort into coming up with this solution and then following through with it.

My next task was to shorten the wires that I had run from the switches in the galley. Initially, I had left lengthy service loops in these wires, not knowing for sure how much wire I might need as I routed each downward into the cockpit locker and lazarette. Now I knew that I had too much slack in these wires, and that I needed to remove as much as 1 or 2 feet from each of them. I do not have a picture of what these wires looked like before I trimmed them. What you see below is the way they looked afterwards.

In this trimming of the wires, I made sure to leave enough for me to install the switches. This was also just enough wire for me to stuff the excess into the back of the three-gang box. This prevented the excess from drooping downward into the cockpit locker where it would be a hazard.

In the close-up below, you can see that I have labeled all three wires for the primary bilge pump. It was especially important for me to indicate which of the two red, 14 AWG wires led to the white wire (for the manual operation of the pump), and which of the two red wires led to the brown wire (for the automatic float switch on the pump).

Earlier, I had installed an AGC/MDL Blue Sea Systems in-line fuse holder (PN 5060) on the red positive wire for the primary bilge pump switch. This fuse, of course, would protect the wire, not the switch.

Also I had earlier installed an in-line fuse holder on the gray positive wire for the emergency bilge pump. Since this wire was 10 AWG, it needed a heavier duty fuse holder. I used an ATO / ATC Blue Sea Systems fuse holder (PN 5064).

With all of the wires ready to go, I grabbed the bilge pump switches and simply plugged all of the female terminals onto the male blades on the backs of the switches.

I would later come back and install the fuses, just before installing the batteries and powering up the new electrical system for the first time.

I thought it would be good to include this close-up picture in this article for the sake of clarity at this moment, and for the sake of future reference.

Satisfied, I slowly stuffed the excess wire into the three-gang box and then I screwed the switches into the holes - the holes that I had pre-drilled before I had ever started this rewiring job.

Finally, I used a zip-tie to pull the black plastic conduit for the bilge pump switch wires out of the way. Now, at last, I could consider this job complete, and I could begin to focus on connecting these hoses to the bilge pumps.

This ends this posting on how I wired the bilge pump switches and the bilge pumps on Oystercatcher, my Ericson 25.