Rewiring from Scratch

Wireman

Wireman

.
Jan 8, 2015
12
Lavranos L34 Port Elizabeth
Hi There,

Sorry to the break the thread, but I am desperately looking for some help to completely rewire a newly purchased L34 (Lavranos 34). After purchasing, two weeks later, we had a cable melt! Smoke bellowing out of the port settee bunk.., not very exciting.

After I had a really good look at the existing wiring I really started pulling my hair out. The boat is close on thirty years old and I suspect that some of the wiring is still from the original installation. Hence the reason to rewire. Attached is an existing diagram that I am working on if there are any takers out there to help a total novice...

Thanks,
Wireman
South Africa

 
P

PGIJon

.
Mar 3, 2012
856
Hunter 34 Punta Gorda
Hi Wireman

Welcome!!! FYI, everyone here is quite knowledgeable and more than willing to share their knowledge. It's probably the most helpful and non-bashing boat site on the web! I'd probably be lost without everyone here!

Here's my advice... Take a look at Stu's posting at: http://c34.org/bbs/index.php/topic,6604.0.html and my next piece of advice is to take as gospel whatever MaineSail posts... have a look at his site: http://www.pbase.com/mainecruising/boat_projects

Jon
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
Mike,

The link Jon sent you to that's mine includes a lot of Maine Sail's material. It covers basic wiring designs for using the reliable but misunderstood 1-2-B switch, as well as varieties with separate and individual switches.

The key is removing the alternator output from the C post of the switch (which is the way most boats are initially wired) and relocating it to the house bank.

One note on your initial diagram: ground is NOT the keel, it's your engine.
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
If this is what you have this basic diagram will work. Note: fuses for batteries need to accommodate starter loads an should be at least 250A type ANL, MRBF or Class T...


 
Wireman

Wireman

.
Jan 8, 2015
12
Lavranos L34 Port Elizabeth
Maine Sail you are THE man !

Thank you very much! Will keep you posted on the outcome.

Thanks,
Mike
South Africa
 
CloudDiver

CloudDiver

.
Sep 8, 2014
2,551
Catalina 22 Swing Keel San Diego
This is just a suggestion from another 'Non-electrician' DIY'er... Like anyone else I try to consult other people's diagrams as examples, get a better understanding of all the components in play and understand all the basics of how things should be done properly in accordance with relevant standards... With that said, I still find wire diagrams somewhat confusing. So, when I installed the 12V harness, fuses, and components on my hand-built motorcycles I found it very helpful to think in terms of "In and Out" with regard to the hot wire. Not sure if that makes sense, and keep in mind my choppers have a very simple harness. 4 fused circuits, 1 head light, 1 tail-light, starter relay, starter, brake light switch, and battery... that's pretty much it. When I have to do the complete rewire of my boat I'll take it one component/circuit at a time...
 
JK_Boston_Catalina310

JK_Boston_Catalina310

.
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Maine Sail said:
If this is what you have this basic diagram will work. Note: fuses for batteries need to accommodate starter loads an should be at least 250A type ANL, MRBF or Class T...


Click to expand
Maine Sail,

I am just curious about the fuse you have between the positive bus and the panel. My panel feed is connected directly to the C on the 1/2/Both/Off switch so my setup is a little different. But it's not fused and when I saw this I was curious.

Thanks,

Jesse
 
Charles Erwin

Charles Erwin

.
Jan 30, 2012
1,142
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Consider routing the alternator cable (and its fuse) direct to the house bank + post instead of the main switch?

Charles
 
Last edited:
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Charles Erwin said:
Consider routing the alternator cable (and its fuse) direct to to the house bank + post instead of the main switch?

Charles
Click to expand
Bingo!!!

I meant to do that but rushed and did not..... Will re-draw later..
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
JK_Boston_Catalina310 said:
Maine Sail,

I am just curious about the fuse you have between the positive bus and the panel. My panel feed is connected directly to the C on the 1/2/Both/Off switch so my setup is a little different. But it's not fused and when I saw this I was curious.

Thanks,

Jesse
Click to expand
When ever you change wire size you also need a fuse that is safe for the smaller wire... For example we don't want to protect 6GA with a 250A fuse...
 
JK_Boston_Catalina310

JK_Boston_Catalina310

.
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Maine Sail said:
When ever you change wire size you also need a fuse that is safe for the smaller wire... For example we don't want to protect 6GA with a 250A fuse...
Click to expand
Ahh, got ya. I didn't catch the change in size at that point when I first looked at the drawing.

Thanks,

JK
 
R

RussT1950

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Jan 26, 2008
60
Catalina 380 Long Beach, Ms
What type of service disconnect switch would you use between the alternator and the house batteries?

Thanks, Russell
 
S

Solstice

.
May 10, 2008
392
Catalina 355 Boston
RussT1950 said:
What type of service disconnect switch would you use between the alternator and the house batteries? Thanks, Russell
Click to expand
I use a Blue Seas mini ON/OFF switch. The knob is removable if you want to ensure it is never accidentally turned off.
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
RussT1950 said:
What type of service disconnect switch would you use between the alternator and the house batteries?

Thanks, Russell
Click to expand
I use the Blue Sea mini battery switches. I place them right in the engine room clearly labeled. They always remain on unless you are working on the engine... Here's one example..


 
D

Dan_Y

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Oct 13, 2008
517
Hunter 36 Hampton
Is there any advantage or disadvantage to placing the alt service switch in the starter hot lead instead? My boat is wired that way for some reason. Do you run the engine with the alt switch open for servicing? Obviously wouldn't want to open the alt switch after the engine is running else rectifiers can get fried. Really nice alt belt by the way! You are way generous with your knowledge!
Thanks
Dan
 
JK_Boston_Catalina310

JK_Boston_Catalina310

.
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Dan_Yuchnovicz said:
Is there any advantage or disadvantage to placing the alt service switch in the starter hot lead instead? My boat is wired that way for some reason. Do you run the engine with the alt switch open for servicing? Obviously wouldn't want to open the alt switch after the engine is running else rectifiers can get fried. Really nice alt belt by the way! You are way generous with your knowledge! Thanks Dan
Click to expand
If the feed for you alternator comes off of the starter, is the feed from the starter connected to the common post on the battery selector switch? I believe that is the common setup. In which case you can just turn off the feed at the selector switch (1/2/both/off switch).

The service disconnect is if you fun the feed from the alternator directly to the battery. Because in that set up the line would always have power and if you are doing work on the engine you might forget to pull the fuse or disconnect the wire at the battery.

I am sure Maine will correct me if I am wrong. But that is my understanding.

Good luck,

Jesse
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
Dan_Yuchnovicz said:
Is there any advantage or disadvantage to placing the alt service switch in the starter hot lead instead? My boat is wired that way for some reason. Do you run the engine with the alt switch open for servicing? Obviously wouldn't want to open the alt switch after the engine is running else rectifiers can get fried. Really nice alt belt by the way! You are way generous with your knowledge!
Thanks
Dan
Click to expand
Dan,

Jesse's answer was correct.

Here's why:

OEM 1-2-B Switch Wiring History http://c34.org/bbs/index.php/topic,4949.msg30101.html#msg30101
 
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