This is what I did. Whether or not it makes any sense to you is something else.
First, I went around to every piece of equipment
on the vessel wired to anything, and labelled it and the voltage and current draw under full load required for everything. I marked the position of all of this stuff on a drawn up plan of the vessel.
Then I drew in red pencil all of the current draws in excess of or up to 100 amps but exceeding 15 amps. That was the anchor windlass
and the cables
for sail and dinghy
handling--even though most would not draw more than fifty amps except for the anchor windlass
. On the plan I drew this wire as heavy tinned cable--and that would run from the anchor windlass to a pony battery (a large one) situated abaft of the chain locker in a sealed water-resistant fibreglass box with a lid that was easily removed, but strong enough to have some light equipment
stowed above it as needed on a temporary basis. Into this heavy cable I placed a 100 ampere overload switch. It is better to have that inconvenience of re-setting the switch than replacing a burned out anchor windlass motor
, if the anchor is jammed. For the other loads, fit overloads as required. If the expected draw is 30 amps max, fit a 40 or 50 amp overload. If your budget
does not run to overloads--use ceramic cartridge fuses
and carry spares.
All of the heavy amperage cables
are tinned copper cables ex-aircraft quality and acquired from military surplus. If you can not get access to this sort of cable second hand--welding cable for welder's 200 amp leads is good enough.
Almost every other load on the vessel is less than fifteen amps, except for the charging current to the pony battery. Because I run the anchor windlass only with the engine
running, and gain another fifty possible amps from the alternator
, I also run the heavy cable from the engine start battery to the pony battery. This way I bypass the regulator
system for the main house battery bank, and just deliver as much as the alternator
can put out to augment the pony battery. After hoisting the anchor, I usually run the diesel
for a half hour or so afterwards as I motor out of the anchorage and set sail when the wind
rises. The pony batrtery is also charged by the solar
array and house battery system, but I fit a blocking diode, so thet using the windlass does not draw down on the house batteries or burn out the charging 6mm tinned twin charging lead from the solar
array and house batteries charger--which is also a mains powered charger
for use in a marina as well as being able to be connected to a gen-set if required to be..
The problem now becomes a lot simpler. You will need a roll of 6 mm tinned DC twin cable. You will also need a few lengths of open-able square conduit, some round conduit (all PVC) with angles and inspection ports
on some of the angles and a couple of packets of countersunk stainless steel
posi-drive screws. I know some people think stainless steel
staples are adequate. I am not among them.
Next you will need some cartridge fuses
, ten, fifteen and some even larger. Automotive fuses can work
here if you can keep them in a dry environment
From here there are two schools of thought. One school
uses two bus-bars, and an earth heavy cable but one kept separate, which also runs the length of the vessel. The bus bars carry the main supply of all DC to all equipment, lights, gas detector etc. Moire on the earth later
The individual equipment is locally switched, (or permanently wired ON via a removable fuse). Equipment is locally fused, and the large and complex switchboards and excess metres of duplicated wires to and from remote
switches are not used--just a few small circuit switches for nearby equipment, the master charging regulators for the house battery and all of the isolator switches for the bilge-pump float switch over-ride switches, as well as any meters that one may feel are required for monitoring equipment or the main bus-bars or house batteries.
The earth cable links everything metal on the vessel EXCEPT for the radio
equipment which has a separate earth plate outside the hull
. The other earth system is part of the lightning
protection and is NOT connected to the negative rail of anything. On a boat, everything must have two wires and a fuse, preferable a flame-proof fuse. The earth linking cable just links anything metal and conductive and connects it to an external lighting
earth--but NOT electronics
equipment which has its own entirely separate earth plate.
Then there is the school
that wants everything double-switched, one at the equipment, the other at a master panel. Lotsa luck--you wire everything in the same way except there are few if any local fuses--and all fuses are set into the long and wire-consuming positive legs of the DC supply in the panel itself, and they are usually those crappy glass fuses set into a spring loaded socket. Their only advantage is speed and ease of replacement, and they are no better than a plug-in automotive fuse--and may in fact be inferior.
I run all of my wires in conduits, waterproof ones set through watertight bulkheads using epoxy
bog, or the re-enterable square ones with two channels for the bus bars, and smaller square re-enterable ones for the take-off's to individual equipment. When one takes off a wire from a bus bar, strip some insulation
, take two turns of 6 mm core
tinned around the wire and solder. To the other end of this wire where it reaches youyr equipment, fit a cartridge sealed fuse. The only exception is in the bilges. Always fuse any circuits to bilge
pumps well clear of the bilge
itself--just in case there are any fumes present and the gas detector has not picked them up. ALL BILGE PUMP
CONNECTIONS MUST BE SOLDERED. Cover the soldered joints with heat shrink tubing, and ideally, the bilge pump
wiring should be in circular conduits specifically for the purpose. A trough-hull and some non-tocic PVC hols wioll do to get the wires out of the bilge as tidily as possible, and from there the square conduit can take the wires to the bus bar or master switch panel. Small re-enterable conduits can hold about two or three circuits--but they seldom hold more than two. Larger re-enterable conduits can hold a whole bunch of circuits very neatly, and if one has labelled the cables as one inserted them, it is easy to isolate them later for further testing or additions.
Bilge ventilation is another topic.