Wiring question for behind-helm fuse block(s)

[thataway]

What else you may want to add, and may require additional fuses:
Fans. I have two in the V Bunk area, and two on the windshield.
Extra lights: LED "night lights" red in the cabin--one near the helm, and one over the galley and table.
LED lights for the cockpit. "spreader" type of lights to face aft.
Some lights for each side--LED--small type or spreader type.
A circuit for a forward light for docking--either mounted on the bow pulpit, or magnetic mount on the anchor.

Extra circuilts for more than one multi function display--one for Radar/GPS sounder, or AIS
separate AIS transceiver
More than one radio.

I like having switches on the side of the console, which I can reach from the bunk to turn on the night lights in the cabin, or lights outside--either to the sides or cockpit for security at night.

[SEA3PO]

Make sure you look on EBAY for marine fuze panel.

I just bought one of those 12 slot ones new for $40 like in your picture.. from Blue Sea (good brand)

What I want it for is to isolate all my electronics connections to a single panel that I can switch on and off... when tied up yet have my radio and interior stuff on a second "house" circuit.

[Sunbeam]

[colbysmith]

As I sit here listening to the wind blow and waiting for the temperature to drop to a minus 20, I'm thinking of spring projects. One of them may possibly involve rewiring. Currently my boat has a 50 amp circuit breaker back by the battery, in the wire leading up to the fuse block behind the helm. 50 amps seems a little high. I'll have to check later what size the wire is again leading from there, but what size should it be with the 50 amp CB? Also, the wire for the anchor windless does not have a circuit breaker at the battery, but rather one located just behind/next to the helm seat. This is nice to use as a "master" switch for the windless switch, but shouldn't the CB be back at the battery with the other CB? Colby

[thataway]

[Captains Cat]

Bob, if you use the breaker for a switch, how do you reverse it?

Charlie

[colbysmith]

I'm actually thinking of putting another CB back by the battery for the Windless wire. While the one up front works nice as a master switch for the windless, I'm more concerned about any shorts between the battery and the CB at the helm. I need to look closer at the main wire then going to the fuse block. There are actually two bus'es (Fuse blocks) in the berth behind the helm, with electronics and lights. I don't imagine there is a lot of draw, the most amperage coming from VHF transmissions and the radar. Otherwise the GPS, two VHF radios while not transmitting, Fish finder, radar and lights probably don't pull more than 10 amps combined. But suppose I should hook up an ampmeter and see what I'm really drawing.

[cbgale]

ABYC Standards should apply. CBs should be within 7"/42"/72" of battery depending on sheathing of wire/wires.

[Sunbeam]

It may be more than you want to wade through, but there was some good discussion of main breaker size and wire/loads to helm in my "Mystery electrical problem" thread started last fall.

Upshot was to figure out your max loads, size the wire appropriately (for round-trip run), and then size the fuse for the wire. I had a 30 amp main fuse and a (IIRC) 12 gauge main helm feed wire, which was basically appropriate for the boat as outfitted (simple/low tech). I calculated my known future loads, plus added a bit of fudge factor for those "little extras," and decided to upgrade to a #6 helm feed wire and a larger fuse (which I say vaguely as I cannot remember right now if I decided to go with 50 or 60 amp fuse after calculating - I'm not with the boat right now).

I've just received most of my new "goodies" and am looking forward to improving things forward of the lazarette I also ordered a windlass (it did come with its own breaker and the main wiring will be the balance of the rolls of #6 cabling I ordered). Whee, project time!

[colbysmith]

Hi Sunbeam, yeah I remember that thread...and had followed it somewhat. I did end up ordering some 6 gauge marine wire off of Ebay for a good price. Even if I don't need to replace the wire that is already on the boat, I may still decide to run another line and keep those two fuse blocks separated.

Bob, regarding the voltage drop, is the drop relative to the amperage, or is the drop constant? Thanks. Colby

[rogerbum]

[colbysmith]

Thanks Roger.

[thataway]

[colbysmith]

2 days in a row of 40 degree weather, but back into ice and cold tomorrow....so anyway I opened the cover a bit and crawled on board my C-22. A few weeks ago I ordered and received some marine 6 gauge "battery cable". Looking today at what was factory, sure looks like 10 gauge wire to me. The Anchor windless is probably 6 gauge (but not quite as heavy as the cable I just bought...probably just sheathing size.) The thermal CB back at the battery is 50 amp. The anchor wire is not fused until just behind the helm seat, where it also has a switchable thermal 50 amp CB. I also bought a 50 amp CB that I will put in the anchor wiring by the battery. Ok, back to the 10 gauge that is factory installed. As of yet, I have had no problems running these items, not necessarily all at once, but many times several at once (including all electronics at night underway....) 2 VHF radios, Radar, Garmin GPSMAP, Navman Fish Finder, and then of course you have the nav lights, cabin lights and bilge pumps. I suppose I could take the time to figure out current draw, but if it ain't broke, why fix it? Yeah, I know.... anyway I'm still rewiring with the 6 gauge cable between the 50 amp thermal CB and the fuse blocks. The boat has the set up with two fuse blocks, so I'll also replace the smaller jumper with the 6 gauge. FWIW, the 6 gauge is pretty thick stuff. (Probably why it's referred to as battery cable! I got the wire ran in the boat today, but out of time so will finish the project next time we get some more warm weather...