wiring idea - tell me why I shouldn't do it

[ktm_2000]

I've got a B25 where my house batteries / switches and panel will be forward in the boat, some of my main loads will be aft in the motor well, like main bilge pump, crash bilge pump, washdown pump, livewell pump.

My thought is that I could run 2 higher gauge 2 wire sets back to a connector bar which would all run the positive and each of the devices would have their ground run to a common ground.

to me the pro's would be that easier wiring, less wiring, I could go to the bilge and on a test with a multi-meter if I had power and ground by putting probes on 2 connections.

I realize that it is not the standard way of doing this, someone (other than me ) troubleshooting would have a tough time if not labled well, what other reasons would there be to not do it that way?

[Bruce]

Are you planning on using in line fuses for each load off the buss bar?

Yes it is opposite of how it's normally done.

[CamB25]

Your most significant load is the engine starter. Be careful about moving the batteries too far away as your wire size will need to increase to limit voltage drop. See charts here: http://www.ancorproducts.com/en/resources

The loads you show in the sketch are relatively low. I would run an "aux" line from your battery switch - through an inline fuse - to a small distribution block (fused) - then to loads. something like this: https://www.bluesea.com/products/catego ... s/ST_Blade

My start/house batteries are in the middle...essentially on top of the stock fuel tank.

[ktm_2000]

gotta love required 2+ hr project meetings where my input is sub 5 min because of this extra time, I made a more pretty diagram to describe what I am proposing, I thought a bit more about it and have even more components to cover.

All items would run from a 4D or a pair of Group31 house batteries which would be under deck near helm. The engine starting batteries would be isolated from house loads and would be located within 6' of the outboard motor(s). my thoughts is that I would have the following items in the old motor well bilge

1. 2000 gph Automatically activated bilge pump (needs 3 wire for automatic with float switch)
2. 3700 gph Manually activated crash bilge pump
3. High water alarm
4. 1100 gph livewell pump
5. Washdown Pump
6. Macerator Pump
7. Bilge Blower - (not sure how much I would need this in future as I/Os will be gone)

From the helm area where the switches are to where the items would be placed is about 12', so 7 items x 12' there would be @84' of duplex wire if done in the traditional manner. The proposed method would only require 4 duplex wires or 48'.
https://photos.app.goo.gl/NwbTbK9e1it8Vyv87

[CamB25]

Skipping the blower, you have 6 loads, 5 of those you will want to control independently (5 pumps), 1 (high water alarm) is always on. You will need 5 switches, 6 circuits. I would home run everything, and use the connector blocks in place of the butt splices if you want a maintenance port close to the loads

I would also set up your bilge pumps to be hot at all times when the battery switch is on (float controls pump), and use a ON/OFF switch on the helm as your manual override. If you store the boat in the water, rig a 24hr circuit for the pumps that pulls power from the battery side of your battery switch (always hot).

Duplex and triplex wire is relatively expensive. You can run a rigging tube down your hollow stringers if you are concerned about chaffing and buy cheaper wire in spools.

I'm not sure I understand what your goal is with this change...

Cam

[ktm_2000]

goals:
Save @$200 in wire, neat and clean, get the ease of maintenance of being able to test connections at the connector blocks in bilge.

The savings isn't as important as the other 2 and it seems that if I just put the connector blocks in the traditional setup I would get that anyway.

as for your other advice, I was expecting to run the automatic bilge pump hot all the time with the rule 3 way switch in an out of the way place so I didn't accidentally turn it off ( before I had the switch inside my center console and wired a buzzer to the light so I would know if my pump was on - which can get annoying when neighbors ask about your boat after a rainstorm)

[CamB25]

consider a 24 hr circuit for the bilge pumps...both. I have a small LED on my helm that is on whenever there is power available to the bilge pumps downstream of the fuses. The thought is that when I'm leaving the boat at the dock, I can simply glance at the LED to ensure by bilge pumps have power available rather than verifying the position of the switches. The On/OFF switches on the helm are the manual override for the floats.

I can send you my working schematics if you want to see the basic arrangement

[ktm_2000]

Cam,

I'd appreciate the diagram for your bilge pump, my approach has worked as a high water alarm as well, I do a lot of live bait fishing and regularly ran with the scuppers plugged and had occasions where the portable livewell shifted and the output hose was sending water inside the boat instead of over the side.

It is interesting how different people solve problems in different ways. I appreciate seeing the different thought processes and being able to incorporate them.

[CamB25]

I followed the general arrangement as shown for the manual only bilge switch here:

https://newwiremarine.com/how-to/wire-b ... mp-switch/

I also had them make a custom switch panel for the boat.

My working schematic:
https://www.amazon.com/photos/shared/Cp ... g_QY16PdO7

I labeled the "float" as "switch" in the schematic. Input 5 (circled) to the On/Off switch comes from my "house" fuse block. The 1 (circled) is power from the 24 hour fuse block which is located adjacent to my main battery switch, on the battery side. Power is available to the float switch 24/7/365 as long as the battery has a charge. I arranged it this way only because I plan to store the boat in the water. If I was trailering, I would connect the 24 hour buss to the switched pole of the main battery switch.

Cam