Cabin Wiring Plan

The Planned Electrical Work web page provides an overview of electrical work and links to pages with more detail, such as this one. The Battery, Charging and Load Wiring web page describes the power distribution to major loads and to the high amperage breaker panel and the lower amperage breaker panel and the layout of the breaker panels.

The High Amperage Panel and Breakers web page and the High Amperage Panel and Breakers web page describe the breaker panels and show their layout. Five feeds from the high amperage breaker panel to the lower amperage breaker panel are designated 24V high priority and 24V low priority, and 12V high, medium and low priority. In the lower amperage breaker panel there are four Blue Sea breaker panels, with 6, 6, 8, and 8 breakers each top to bottom and respectively support 6 12V high priority, 6 12V medium priority, 8 12V low priority, and 4 each 24V high and low priority. The panel wiring is difficult to access and therefore led back to a set of terminal blocks in the area behind the breaker panel, with a total of 32 terminals pairs (two blocks of 6 and one block of 8 for 12V and two blocks of 4 for 24V).

From the area behing the breaker panels, wires will be routed aft then forward, to systems in the same area, or over to the starboard side and then forward. Wires run aft go to the stern, the steering pedestal or steering pedestal bars, and to the mizzen mast. Wires run forward go to the port water system, the galley, the bilge, the main mast, the main cabin, the fore cabin, or the bow. Wires run to the starboard side, then forward run to the starboard side water system (vanity and shower), the navigation station and the vanity area. Some of the circuits are run to multiple places. For example the navigation lights circuit runs to the stern, the bow, the steering pedistal for the compass light, to courtesy lights in the cockpit footwell.

Cabin positive load wiring will primarily use Ancor Marine Grade Primary Wire - 10 AWG purchased in 100 foot spools in white, red, black, and yellow. The white and yellow will be used for 24V loads, and the red and black for 12V loads. It is important to wire the ground side of any load to the right terminal block so that the current returns on the correct shunt. All 12V loads will share a common shunt. In addition to a 24V shunt there will be two shunts designated as large load #1 and large load #2. These will be swapped among A/C & heat, watermaker, galley inverter and forw inverter. Ground wiring will primarily use AWG #2/0, AWG #2, or AWG #6 yellow or black cable as distribution to places with multiple loads or to large loads, then distributed to individual smaller loads with AWG #10 yellow or black wire.

The breaker panels come with 15A breakers. Some may be replaced with smaller breakers. All wires from the breakers to the terminal blocks will use AWG #10 wire with Anchor AWG #10-12 ring terminals with heat shrink and adhesive on each end. Wires will be run for the 3 spare breakers. With 28 circuits the panel to terminal block alone uses 56 ring terminals so a 100 pack for #8 screws and 25 pack for #10 screws was initially purchased. For very small loads such as lighting distribution wiring AWG #14-16 ring terminals for #8 screws will be used along with AWG #14 wire.

Wires from the breakers in the high amperage loads will be AWG #6 or larger and run directly to the loads or to solenoids and then to the loads rather than use large terminal blocks. The terminal blocks behind the lower amperage panel will use three Blue Sea 30 Amp 8 Circuit Terminal Block for the 12V loads, and two Blue Sea 30 Amp 4 Circuit Terminal Blocks for the 24V high priority and low priority loads.

Terminal blocks will be used in places where many circuits are routed or where circuits are routed through difficult spaces. These are likely to be Blue Sea 20 Amp Terminal Blocks where loads are 20A or less. Some of the 12V and 24V circuits lead to the coil of a solenoid behind the high amperage breaker panel where the actual load is connected. This reduces wire length for high amperage loads and avoids bringing heavy wires to the lower amperage breaker panel. The Blue Sea A-Series used in the lower amperage breaker panel are available up to 50A but no breaker larger than 15A will be used.

Load wiring will be primarily white for 24V+, red for 12V+, yellow for 24V- and black for 12V-. Separate bus bars will be used for 24V- high priority, 24V- low priority and the three 12V- priorities. Each of these may be on their own shunt in the future though immediate plans are to just separate 12V and 24V plus measure a few large loads. To identify wires for individual circuits, wires are marked at terminal blocks and periodically along wire runs with colored electrical tape. With no engine room heat, tape is not expected to get hot enough to soften the glue. The consequence of losing a piece of tape used for marking is more an annoyance than a problem.

Circuits will be numbered, expressed as a three nibble hexidecimal number. A base four system of with four tape colors will be used to mark the wires. A hex digit is two nibbles and takes two tape stripes to represent. The top nibble, 0-3, is the circuit panel, 12V hi pri, 12V med pri, 12V low pri, 24V. This first tape stripe will be wider than the others to tell which way the number is read. The rest of the number is the circuit panel position, numbered up and down on the left column first, then the right, starting at zero. The colors are green, yellow, purple, and gray. These colors provide contrast with red, white, and black wire, but not yellow wire. Bilge pump wires are connected directly to bilge pump switches and then the battery switches. The windless will be connected to the high amperage breaker panel, though a spare in the lower amperage breaker panel plus a solenoid could be used. These directly connected wires will use a different coding with a blue band of tape.

The following table lists the lower amperage breaker panel circuits by destination. Note that any given circuit (such as navigation lights) may go to multiple destinations.

Circuits listed by destination of the circuit
Where	Circuit	Num	Mark	Feed Group	Amps	Description
stern	nav lights	0x03		12V high pri	15A	The stern light will be replaced with LED.
stern	autopilot	0x31		12V high pri	4A	The Type 1 drive unit (EV-2 system) consumes 18-36W or 1.5-3A at 12V. The Type 2 drive unit (EV-4 system) consumes 48-72W or 2-3A at 24V. The EV-2 autopilot is not available in 24V, only the EV-4 system which is oversized but comes in 24V.
steering	instruments	0x03		12V high pri	15A	The helm multifunction display (aka chartplotter) at the steering pedestal will be on the instruments circuit.
steering	nav lights	0x03		12V high pri	15A	When the NAV lights are on the compass light on steering pedestal will also be on as well as some red courtesy lights.
mizzen	deck lights	0x20		12V low pri	5A	Either one or two spreader lights will be added at the mizzen mast. These will be LED and so well under 5A total.
mizzen	radar	0x30		24V high pri	5A	The radar radome power consumption is 17W or less than 1A at 24V.
systems	cockpit lights	0x11		12V med pri	5A	Cockpit lights will be switched in the cockpit and should be under 1A with red lighting and white lighting switched within the cockpit. Minimal red courtesy lights will be connected to the nav lights circuit.
	storage lights	0x12		12V med pri	5A	The storage light circuit will lead to switched lighting in the engine (motor) compartment, storage portions of the sizeable aft bilge area, and switched lighting for wiring, breakers, and systems in this area.
	gray water	0x26		12V low pri	10A	Multiple gray water tanks and pumps serve the refrigerator drain, galley drain, vanity drain, and shower drain.
	autopilot	0x31		24V high pri	5A	The autopilot control unit will be located in the systems area. The autopilot control unit consumes under 1A.
	refrigeration	0x32		24V high pri	5A	The refrigeration system should consume under 5A.
	watermaker	0x33		24V low pri	5A	The watermaker, when installed, may consume between 5A and 20A, depending on the size of the system that is installed.
nav station	nav station	0x00		12V high pri	5A	The navigation station will have some switched lighting plus a multifunction display (chartplotter) and some additional displays to monitor instruments or systems. Minimal lighting for the nav station will be on this circuit since full cabin lighting is medium priority.
	instruments	0x01		12V high pri	15A	The instruments circuit provides power to the speed/depth transducer, and wind transducer. There may be a raymarine hub which is switched off in the nav station if instruments are not enabled. When underway the instrument circuit should always be on.
	AIS VHF sat	0x02		12V high pri	15A	The AIS transceiver and VHF radio will be located in the nav station. This circuit will also power the Iridium Go satellite unit and the Starlink router if installed which will also be located at the nav station. Separate switches in the nav station will allow each to be enabled or powered off.
	cabin lights	0x10		12V med pri	5A	Cabin lights will be all LED which should consume well under 5A. Any cabin light that is not LED will be replaced.
	12V sockets	0x21		12V low pri	15A	Sockets will be fused for 15A (or the current limit of the sockets if lower) but will primarily be used for USB charging and so draw under 1A in normal use.
	audio system	0x23		12V low pri	20A	The old audio system was located above the pilot berth. The old system will not be used. A new system will be purchased at some and may end up in the nav station.
starboard	forw pump	0x14		12V med pri	5A	The forward cabin fresh water pump is located under the settee on the starboard side.
starboard	forw heater	0x25		12V low pri	25A	The forward cabin fresh water heater is located behind the starboard settee aft backrest.
port	galley pump	0x13		12V med pri	5A	The galley fresh water pump is located under the settee on the port side.
port	galley heater	0x24		12V low pri	25A	The galley fresh water heater is located behind the port settee aft backrest.
galley	cabin lights	0x10		12V med pri	5A	Cabin lights will be all LED which should consume well under 5A. Any cabin light that is not LED will be replaced.
	12V sockets	0x21		12V low pri	15A	Sockets will be fused for 15A (or the current limit of the sockets if lower) but will primarily be used for USB charging and so draw under 1A in normal use.
	gray water	0x26		12V low pri	10A	Multiple gray water tanks and pumps serve the refrigerator drain, galley drain, vanity drain, and shower drain.
	galley inverter	0x36		24V low pri	50A	A 50A breaker can support 1200W but 24V inverters are hard to come by. If a larger breaker is needed, then the breaker will be located in the galley near the inverter.
main cabin bilge	cabin 12V bilge pump	--		12V	5A	One lower capacity 12V bilge pump will be located in the main cabin bilge. Bilge pump connections will bypass the breaker panel.
	forw 12V bilge pump	--		12V	5A	One 12V bilge pump will be located in the forward bilge area. Bilge pump connections will bypass the breaker panel.
	24V bilge pump	--		24V	5A	One 24V high capacity will be located in the main cabin bilge. Bilge pump connections will bypass the breaker panel.
mast	instruments	0x01		12V high pri	15A	The instruments circuit provides power to the multifunction display, speed/depth transducer, and wind transducer. There may be a display or raymarine hub which is switched off in the nav station if instruments are not enabled.
	nav lights	0x03		12V high pri	15A	Less than 5A with LED lights. Goes to stern, bow, compass light, likely some courtesy lights.
	steaming	0x04		12V high pri	5A	The steaming light is mounted on the front of main mast. If it is not currently an LED light it will be replaced with an LED light.
	anchor light	0x05		12V high pri	5A	The anchor light is mounted on the top of main mast. If it is not currently an LED light it will be replaced with an LED light.
	deck lights	0x20		12V low pri	5A	Either a steaming light with integrated foredeck light or one or two spreader lights will be added to the main mast. These will be LED and so well under 5A total.
cabin	cabin lights	0x10		12V med pri	5A	Cabin lights will be all LED which should consume well under 5A. Any cabin light that is not LED will be replaced.
	12V sockets	0x21		12V low pri	15A	Sockets will be fused for 15A (or the current limit of the sockets if lower) but will primarily be used for USB charging and so draw under 1A in normal use.
	gray water	0x26		12V low pri	10A	Multiple gray water tanks and pumps serve the refrigerator drain, galley drain, vanity drain, and shower drain.
	AC/heat	0x34		24V low pri	50A	It might be that more than a 50A breaker is needed to handle the turn on surge. If that is the case a Series C breaker is needed and that would be mounted in the cabin.
vanity	cabin lights	0x10		12V med pri	5A	Cabin lights are thought to be all LED which should consume well under 5A.
	12V sockets	0x21		12V low pri	15A	Sockets will be fused for 15A (or the current limit of the sockets if lower) but will primarily be used for USB charging and so draw under 1A in normal use.
	gray water	0x26		12V low pri	10A	Multiple gray water tanks and pumps serve the refrigerator drain, galley drain, vanity drain, and shower drain.
	vanity inverter	0x37		24V low pri	50A	A 50A breaker can support 1200W but 24V inverters are hard to come by. An 800W or 1000W inverter should be sufficient for the vanity unless a guest plugs in a blow dryer.
bow	nav lights	0x03		12V high pri	15A	Less than 5A with LED lights. Goes to stern, bow, compass light, likely some courtesy lights.
	washdown	0x22		12V low pri	5A	A washdown pump is available with switch and hose in the chain locker.
	windlass	--		24V	100A	A windlass will be installed. At 24V it may take as much as 80A. The windlass will be connected directly to a 100A thermal breaker on the hi-amp breaker panel.