12 volt Electrical panel rebud

[Redlegmsg66]

Bought a 1973 Ericson 32 in May. Boat is in good condition however there are a few problems that I will address this winter while the boat is out of the water. The panel with switches for all the lights, bilge pump, blower motor etc needs to be replaced. im a decent 11 volt electrician, biggest concern is continuity of the existing wiring. my plan is after batteries are disconnected to tag and remove all the wires from the panel. build an updated panel and rewire everything back together. Additional options include making a small switch panel with 12v power source to check each circuit individually, I can also do a continuity check on each wire. I plan on replacing all of the lights, mast, navigation, interior with LED lights at the same time. Im open to thoughts and suggestions especially if anyone has undertaken a similar project.

[joe_db]

I did this job some time ago.
Be warned it can snowball, my wiring looked like this. I ended up replacing most of it.

[joe_db]

At first I ran all the wiring straight to the circuit breakers, but you get multiple wires on one breaker and it eventually becomes a big mess.

[joe_db]

I then redid it by using terminal strips to connect the boat wiring and then feed each breaker with one wire.
This IMHO is a vastly better way to do the job.

[joe_db]

I added two voltmeters, one for each battery, and an ammeter for the house battery. The house bank meters have a green background. The engine bank is blue. The engine bank must be off in this photo. The control for the Blue Sea automatic combiner is below the meters.
Speaking of which, I use mostly Blue Sea products. They are high quality, which is good, and show up on eBay cheap now and then, which is even better

[joe_db]

I used this Blue Sea panel for battery management. It makes it easy to start off the house bank if needed and the cross connect also allows charging both banks if the automatic combiner fails.

[Redlegmsg66]

Joe, Thanks for the quick reply. how much of an issue was it to pull new wire? I would like to do that for peace of mind however im concerned that trying to pull new wire will be a mess. The obvious is to connect new wire to old and just pull it through, still potential for wires to get caught somewhere.

[joe_db]

Some of it was easy and some was a huge pain. The cabin light wiring is sealed between the liner and deck and is impossible to replace.
You have to pick your battles

[ndutton]

Complete replacement of the electrical system can be one of the most rewarding projects you'll do on the boat. A few thoughts:

• Wiring sandwiched between hull/deck and their respective liners is not running through a void, it's stuck in there permanently so attempting to pull replacements through like in a conduit will be a source of frustration. Find other pathways to achieve the same goal even if it means fabricating wire covers. That's what I did for my overhead cabin lighting and mast wiring. There are ways and with a little care and ingenuity the results can look factory original.
• When designing your new system remember that for the same load wattage, 12V circuits have 10X the amperage of 120V circuits so size your wires accordingly including a minimum 25% extra amperage capacity. Overbuild for safety.
• Spare no expense for quality. Electrical design is all about fire prevention and a fiberglass boat is the last place you want to deal with a fire. We were always told at the boat plants that a 30 foot boat will burn to the waterline in about 10 minutes. I personally was involved in fighting a mold shop fire of a Columbia 45 hull in the mold. Fiberglass burns with a frightening ferocity like I'd never seen before or since.

[joe_db]

My cabin light wiring is 16 gauge and ran all the way up the starboard side and down the port side, so the aft-most port cabin light was on 70 some feet of wire round trip!
I never could replace all of it, but the circuit is now fed from both ends and forward too, so the lights not on new wiring have 10-15 feet of old wire at most.

[ndutton]

Custom fiberglass wire cover for cabin lighting

[ndutton]

Teak wire cover for mast wiring

[Redlegmsg66]

Did you make the covers or were they commercially made? looks good

[ndutton]

Did you make the covers or were they commercially made?

I made them. There are ready made wire cover systems, i.e. Wiremold available from Home Depot and Lowe's but for my taste they don't blend into the original design well enough. That's my personal character flaw though. I had experience with the materials involved and a sufficient workshop to make it happen so custom fabrication was the decision for my boat.

[joe_db]

IMHO this is a bit like eating an elephant, you have to do it in small pieces.
I would start with the primary battery cables, battery management, the terminal strips to connect the panel to the boat, and the panel.
Once that is in place you can go about rewiring the boat itself as needed.
I would make sure do take notes, take photos, and label wires. You WILL forget what goes where.
If you think you are going to do any work at all with wire thicker than 10 gauge, by this or the equivalent:

https://www.harborfreight.com/hydraulic-wire-crimping-tool-66150.html

It will pay for itself many times over vs. paying a local battery shop to make your cables.