Re-Wiring During Refit

[skipmac]

Correction, Defender in Waterford CT.

[evm1024]

Hi, Great project(s) to get your feet wet with. Before getting too far along I would suggest that you pick up a copy of Calders "Boatowner's Mechanical and Electrical Manual". Read the sections on electrical and in general follow the "rules".

I've rewired most of my current boat. The prior owners rewired and used single strand boat wire. AC circuits were the normal black, white and green with DC circuits red and white. In the past DC was red and black as you are planning but became red and yellow so as to avoid the chance that someone cut into a black wire thinking that it is DC ground and getting AC hot (and dying). Back to my boat - by using white for the ground I now have the risk of getting hold of AC neutral. Cut that wire and you run the risk of completing a live AC circuit through your body.

My suggestions are to:

use boat cable (as you are)
use triplex cable for AC circuits (black, white, green)
use duplex cable for DC circuits (red, yellow)
Label everything at both ends
Use the correct size wire and breaker it
get a good crimping tool and crimps
get heatshrink and a heat gun
read the book

Buy a 1000' reel of #14 duplex safety wire (red yellow) and use this for your "standard". Don't hesitate to use a heaver gauge wire for anything that needs it.

In my town we have a marine surplus store that sell things like left over wire on consignment. Any leftover cable could be sold in a place like that assuming that you have one near by. Buying 1000' can give a significant discount per foot (genuine dealz). And selling the leftover may make up some of the cost.

Lastly two thoughts - Many of the rules (ABYC or ISO) exist not because people like making rules but rather in an effort to prevent further deaths. And, this project is a learning experience which will set the stage for your future projects. Learn the right things (read the book...).

Regards!

[Noreastern]

Thanks EVM,

I have been using Calder's book as reference since I bought my first sailboat with relatively complex systems (Catalina 27) in 2000. It is one of the best books written on boat systems I think as do many. However I would never call it a "bible" as some people do. I like things much more simple then what he believes is the proper way. For instance I would rather not have AC on the boat at all. I have seen enough problems with AC systems on boats which were supposedly wired correctly. I have my own system which is most likely not code but one I am comfortable with.

Worked professionally with electronic and electrical systems my whole life so much of this project is not new to me. In fact of the whole refit project this is the part I am most comfortable with. Now filling in seven thru-hulls and fixing blisters I am very worried about but that is another thread.

[Noreastern]

Skip,
Yes have been to Defender many times and will be there again in March for their spring warehouse sale. Like the Maine Boat-builders show in Portland I usually go every year.
Brian

[Noreastern]

Picture being worth a thousand words. Here's our blank canvas for starting the re-wiring of this refit. Image is facing aft. House batteries will be in cutout just forward of the engine compartment. To starboard will be the nav station were the old ice box was. Nav station will be facing forward. Planning to put a starting battery under the nav station seat. This should keep all heavy gauge battery cables four feet or less. Distribution panel, battery cutoff switches, external regulator, battery monitor and main switch box will be behind or mounted on panel on bulkhead forward of what will be the nav station table. VHF and stereo will be on panel against the starboard hull in nav station. Refrigerator/freezer will be to port just forward of galley. Electric bilge pumps are located directly under engine. Internal auto pilot will be about six feet aft of nav station near rudder post under cockpit. Radar (chart plotter if we get one) display will be movable from nav station to companionway on brackets. We have a manual windless so that wiring is N/A.

Second picture is some of the original wiring I will be using as a "fish" for new wiring.

[ashmun]

All good advice and postings. I don’t mean to repeat as much as to emphasize or ditto the previous posting’s recommendation to purchase and read the following books:

Nigel Calder's Boatowner's Mechanical and Electrical Manual (Ditto on the bible comment)

Charlie Wings Marine Electronics Books has good explanation and examples

Ed Sherman also has several good marine electrical books.

After reading these books, I’d recommend:

1) Creating an electrical inventory worksheet (item, watts/amps, usage during night sailing and more). This will help you design and size your circuit breaker panel, figure out your battery sizing and your charging needs (e.g. alternators, solar, wind generators).

2) Create a wiring diagram that includes which wires run through the engine room (higher heat, thicker wire), which wires will be bundled/conduit, where the circuit protection and switches will be located and so on. At some point you’ll need to make decisions on lightening protect (or not), grounding/bonding and whether your running an SSB.

3) As many have mentioned, there are several DC marine wiring calculators available on mobile devices that follow ABYC E-11 wiring standards (or ISO). Some of them will save/email the wire runs so you can sit in the boat, even the engine room, with a tape measure and start documenting all the wire runs you will need in the calculator (the calculators at a minimum should give you the wire size, voltage drop and ampacity and some will even some the wire amounts by size, type and wire color so you know whether your buying a few feet or as some already mentioned by the roll; 25’ 50’, 100', etc.).

4) For rewiring an entire boat, I’d recommend investing in good electrical tools (ratcheting crimpers, good wire strippers, etc.) that will improve the quality and efficiency of job. This includes borrowing or buying a lug crimper. The marine environment can wreck havoc on wiring, so also invest in good marine wiring, marine connectors, heat shrink tubing for the connectors and so on, so that you’re not having to repair the work you did or risk damage to equipment. This money saved on less expensive wiring and connectors is little compared to your labor and the potential damage to expensive motors (e.g. windlass, pumps) and electronics when the corrosion eventually increases voltage drop.

5) In addition to using the correct wire size, ABYC also has specification on the installation (e.g. connector types, supporting the wire at specific lengths, circuit protection, and more).

6) And remember, that unlike a car that is ground to the chassis, wire lengths for wire size calculations on a boat are almost always round trip (positive and negative length) unless you’re grounding to the engine (e.g. alternator, starters).

There are a number of good web sites that list tips, tools and recommendations in addition to the wealth of knowledge on this forum. And in the past I’ve found good wire design examples that the other boaters have generously posted. I've even found designs for the model boat that I was re-wiring.

Good luck on your project and please don’t hesitate to post questions during the project.

Julia
w/v Esprit