DC Electric System Layout

June 5, 2016

 

DC Branch Circuit Panel

There are three branch circuit panels:

Bridge Branch Circuit panel, is a standard 19" rack panel and is located in the DC rack of the bridge.
Port Hull Branch Circuit Panel, located in the branch circuit box above the port tank.
Starboard Hull Branch Circuit Panel, located in the branch circuit box above the starboard tank.

 

Bridge Branch Circuit Panel

# Breaker Max.
A
Breaker A Cont. Load Interm. Load

House or Hulls

             
First row, breaker used as switch          
1 Navigation lights 8 10 X   House
Anchor light 2 10   X House
Search light 10 20 X  House
Aft light port 10 20 X   House
Aft light starboard 10 20 X   House
Stereo 2 20 X   House
Instruments 5 10 X   House
Instrument lights 5 10 X   House
VHF RAY 54 DSC (transmit power) 5.8 10 X   House
10 SSB (transmit power) 30 30   X House
Radar   20  X   House
Windshield wipers  Speich 5 A each (5 total) 25  30   X House
Electronic horn (Marco 5712) 6  10   X House
 Spare          
 Spare          
16  Spare    10      House
Second row, breaker always on          
1 Port cabin lights 6 x 4.16 A (50W) 25 20   X House
Starboard cabin lights 6 x 4.16 A (50W) 25 20   X House
Bathroom lights 17 20   X House
Bridge  lights and outside bridge 5 20   X House
Galley and dinette lights 5 20   X House
Boat deck 10 20   X House
Aft deck lights 10 20   X
Emergency lights LED only 10 10   X House
Radar arch lights 10 20   X House
10 Bridge 12 V outlets 5 10   X House
Dinette and Kitchen air circulation blowers 5 20   X House
 Spare          
 Spare          
 Spare          
 Spare          
16  Spare    10      
Tender crane 90 200   X House

 

Port Hull Branch Circuit Panel

# Breaker Max.
A
Breaker A Cont. Load Interm. Load

House or Hulls

             
  First row          
Port fresh water system pump 15 20   X Motorized breaker
Port water maker  21.5 20   X Motorized breaker
Port macerator pump 16 20   X Motorized breaker
  Motorized breaker
Port hull lights 20 20   X To relays
  Port emergency lights         To relays
Port aft steps lights 10 10 X   To relays
Bridge step lights 10 20   X To relays
Port cabins 12 V outlets 5 10   X Hulls
Galley 12 V outlets 5 10   X Hulls
Port hull 12 V outlets 5 20   X Hulls
Port WC (5 A + 25 A) 30 30    X Hulls
             
           
Port bilge pumps Rule 1500 (4.8 A each) 4.8 20  X Hulls
Port instruments 2 10 X   Hulls
Port computer 20 X   Hulls
Port fuel pump (Marco 7.5 A) 7.5 10   X Hulls
Port engine room blower Jabsco 4"  11 20   X

To relays

Port sea water 1  pump 15  20   X Hulls
Port sea water 2  pump 25 30    X Hulls
Inverter (port) 80 200   X Hulls

 

Starboard Branch Circuit Panel

Breaker Max.
A
Breaker A Cont. Load Interm. Load

House or Hulls

           
First row          
Starboard fresh water system pump 15 20   X Motorized breaker
Starboard water maker  21.5 20   X Motorized breaker
Starboard macerator pump 16 20   X Motorized breaker
Auto pilot  30 X   Motorized breaker
Starboard hull lights 20 20   X To relays
Starboard emergency lights          To relays
Starboard aft steps lights 10 10 X   To relays
Bridge step lights 10 20   X To relays
Starboard cabins 12 V outlets 5 10   X Hulls
Dinette 12 V outlets 5 10   X Hulls
Starboard hull 12 V outlets 5 20   X Hulls
Starboard WC  ( 5 A + 25 A) 15 20   X Hulls
             
           
Starbd bilge pumps (Rule 1500 4.8 A each) 4.8 20  X Hulls
Starboard instruments 2 10 X   Hulls
Starboard computer 20 X   Hulls
Starboard fuel pump (Marco 7.5 A) 7.5 10   X Hulls
Starboard engine room blower Jabsco 4"  11 20   X

To relays

Starboard sea water 1  pump 15  20   X Hulls
Starboard sea water 2  pump 25 30    X Hulls
Anchor windlasses (starboard) 80 200   X Hulls

 

 

Wire Equivalents

AWG = American Wire Gauge

1/0  AWG  53.49 mm2
1  AWG  44.21mm2
2  AWG  33.62 mm2
4  AWG  21.15 mm2
6  AWG 13.30 mm2
8  AWG  8.37 mm2
10  AWG  5.26 mm2
12  AWG  3.31 mm2
14  AWG  2.08 mm2
16  AWG  1.31 mm2

 

Wire Sizes

Wire size calculated for a 10 m distance, one way, since the return is done with oversized common negative wires.

Load,
A
3%  voltage drop,
 AWG 
3 % voltage drop
 mm2
10%  voltage drop,
 AWG 
10 % voltage drop
 mm2
10

 10

5.26

 14

2.08
20  6 13.30  12 3.31
30 4 21.15 10 5.26
50  2 33.62 8 8.37
100  0 53.49  4 21.15

 

DC Wire Harnesses

Hull Harnesses

The two harnesses go from the two hull branch circuit panels to the two big junction boxes above the fuel tanks.

  Load A Size mm2 Color
Hull 12 V outlet 16 10 Red
Hull emergency lights LED only 1 violet
Hull lights (6 x 60 W, 30 A max) 30 16 Blue
Lights, aft steps, house steps 15 6 Gray
       
Fuel pump, engine room. 10? 6 Gray
Blower, engine room. Jabsco heavy duty 12 6 Gray
Fire hydrant pump, engine room. 10? 6 Gray
Salt water pump, engine room. 10? 6 Gray
       
Fresh water pump 10? 10 Red
Watermaker or equivalent 30.0 ? 16 Blue

 

Steering Harness Starboard

The two harnesses go from the two junction boxes above the fuel tanks to the aft platform of the boat.  Beside the bilge pumps on the starboard side there is the shore television and shore telephone cable.  On the starboard side the wires run parallel to the shore power cable.

  Load A Size mm2 Color
Bilge pump, aft platform. Rule 1500 4.8 60 Brown
Bilge pump, aft platform. Negative 4.8 60  
Bilge pump, aft platform. Float switch - -  
Water level alarm, aft platform      
Rudder position indicator - -  
Autopilot negative - 25 Black
Autopilot motor 32 25  
Autopilot left 6 6  
Autopilot left 6 -  
Telephone in  - -  
Television in - -  

 

Crane Harness

The harness goes from the branch circuit panel to the underside of the starboard side of the boat deck.

  Load A Size mm2 Color
Negative - 50 FG7
Crane 100 50 FG7
Aft platform light 10 6 Blue
Aft navigation light 10 6 Blue
Dinette air extractor 10 6 Gray
Spare 1 2.5 White
Spare (small air extractor?) 1 2.5 Brown

 

Other Side of Crane Harness

The harness goes from the branch circuit panel to the underside of the port side of the boat deck.

  Load A Size mm2 Color
Negative - 50 FG7
Aft platform light 10 6 Blue
Aft navigation light (spare) 10 6 Blue
Kitchen air extractor 10 6 Gray
Aft outside ceiling light 20 16 Blue
Spare (small air extractor?) 1 2.5 Brown
Video camera power 1 2.5 White
Video camera coax cable - Coax White
Relais wire for door switces for kitchen and dinette - 9 x 0.75 -

 

Bridge - Kitchen and Dinette Lights and Speaker Harnesses

The harness goes from the branch circuit panel to the various ceiling light and emergency lights and speakers of the kitchen, dinette and bridge..

  Load A Size mm2 Color
Kitchen lights (4 x 5 A = 20 A) 20 6 Blue
Dinette lights (4 x 5 A = 20 A) 20 6 Blue
Kitchen - Dinette emergency light  2 2.5 Blue
Kitchen - Dinette lights negative 40 16 Black
Port bridge lights (4 x 5 A = 20 A) 20 6 Blue
Starboard bridge lights (4 x 5 A = 20 A) 20 6 Blue
Bridge emergency light  2 2.5 Blue
Bridge lights negative 40 16 Black

Relais wire for stair switces for kitchen, dinette and bridge

- 9 x 0.75 -
Bridge steps lights (both steps) 2 2.5  Blue
Bridge speakers - 2.5 Red - black

 

Aft Harnesses

The two harnesses go from the two junction boxes above the fuel tanks to the aft of the boat, that is to the engine rooms and engine rooms entrance. The wires follow two paths, the outside hull panels and the floor .

  Load A Temp C Length m Size mm2 Color
Positive, engine room 12 V outlet 16 60 10 10 Red
           
Emergency lights (3).  LED,  0.058 A each < 1 40   1 Blue
Emergency lights (3).  Switch wire - -   2 x 0.75 Gray
           
Dome light, engine room entrance. 60 W 5.0 60   2.5 Blue
Dome light, engine room entrance.  Switch wire - -   2 x 0.75 Gray
Lights, aft steps, swim platform 10? 60   6 Gray
Bilge pump, engine room entrance. Rule 1500 4.8 60   2.5 Brown
Bilge pump, engine room entrance. Float switch - -   2.5 White
Bilge pump, rudder comp. Rule 1500 4.8 60   2.5 Brown
Bilge pump, rudder comp. Float switch - -   2.5 White
           
Dome light, engine room . 60 W 5.0 60   2.5 Blue
Dome light, engine room.  Switch wire - -   2 x 0.75 Gray
Bilge pump, engine room. Rule 1500 4.8 60   2.5 Brown
Bilge pump, engine room. Float switch - -   2.5 White
Fuel pump, engine room. ? 60   6 Gray
Blower, engine room. Jabsco heavy duty 12 60   6 Gray
Blower, engine room.  Switch wire - -   2 x 0.75 Gray
Sea water pump 1, engine room. 20? 60   6 Gray
Sea water pump 2, engine room. 20? 60   6 Gray
Salt water pump 1.  Switch wire - -   2 x 0.75 Gray
Spare - -   6? Gray
           
Dome light, above fuel tank. 60 W 5.0 40   2.5 Blue
Dome light, above fuel tank.  Switch wire - -   2 x 0.75 Gray

 

Forward Harnesses

The two harnesses go from the two junction boxes above the fuel tanks and on the side to the forward of the boat.  The wires follow the outside hull panels.
The anchor wires are only on the starboard side.

Black wires are always and only negative 12 V and are not listed.

Port Side

  Load A Length m Size mm2 Color
         
Bilge pump, forward of water tank. Rule 1500 4.8   6 Brown
Bilge pump, forward of water tank. Float switch 4.8   6 Gray
Bilge pump, anchor room. Rule 1500 4.8   6 Brown
Bilge pump, anchor room. Float switch 4.8   6 Gray
WC 40 10 Red
12 V Outlets 10 Red
Watermaker 20.0 ?   10  Blue
Fresh water pump 5.0   2.5 Brown
Macerator ? 10 Brown
Dome lights, forward hull. 10.0   2.5  Blue
Dome lights, forward hull.  Switch wire -   2 x 0.75 Gray
Dome light, anchor room. 60 W 5.0   2.5 Blue
Dome light, anchor room.  Switch wire -   2 x 0.75 Gray
Emergency lights (3).  LED,  0.058 A each < 1   1 Purple
Emergency lights (3).  Switch wire -   2 x 0.75 Gray

 

Starboard Side

  Load A Length m Size mm2 Color
Bilge pump, forward of water tank. Rule 1500 4.8   6 Brown
Bilge pump, forward of water tank. Float switch 4.8   6 Gray
Bilge pump, anchor room. Rule 1500 4.8   6 Brown
Bilge pump, anchor room. Float switch 4.8   6 Gray
WC 40   10 Red
12 V Outlets 40   10 Red
Watermaker 20.0 ?   10  Blue
Fresh water pump 5.0   2.5 Brown
Macerator ? 10 Brown
Dome lights, forward hull. 10.0   2.5 Blue
Dome lights, forward hull.  Switch wire -   2 x 0.75 Gray
Dome light, anchor room. 60 W 5.0   2.5 Blue
Dome light, anchor room.  Switch wire -   2 x 0.75 Gray
Emergency lights (3).  LED,  0.058 A each < 1   1 Purple
Emergency lights (3).  Switch wire -   2 x 0.75 Gray
         
Anchor windlasses 200 ?   70 Red
Anchor windlasses. Negative 200 ?   70 Black
Anchor windlasses. Switch wires (5 wires in one)     1

 

 

Top Bridge Panel Harnesses

The power for the top instrument panel of the bridge goes from the branch circuit panel to the top panel passing through the port side.

The table below is no longer completely valid.

  Load A Size mm2 Color
Negative 2 x 25 + 1 x 25 Black
Stereo equipment 20 10 Red
Horn switch wire  2 2 x 1 Violet
Instrument lights 5 6 Brown
VHF 20
SSB and hailer NC and cut below 20 pale blue
Windshield wipers  30 16 Blue
Instruments 1 5 16 ?

White-violet wire from below to the top instrument panel of the bridge is not connected.
A pale blue, cut wire from below to the top instrument panel of the bridge goes to the same terminal block as the VHF radio. 
Not connected.
A 4 pole wire, from the boat deck to the top instrument panel of the bridge is not connected.

The second push button from the left on the panel above the steering goes to the ground and to the boat deck (black).  Can be used for the horn switch relay.

 

Upper Structure 

Wires that start at the bottom of the upper structure.

Starting always from the front.  Black not listed, always -12V.

 

Starboard Side

TV antenna   
Red Front bedroom 12V
Gray Front bedroom bed reading lamps
Brown Side lights
     
Black red Speakers
     
Blue (big)   
Gray   
Violet Emergency
     
2x9 + 2x1 light controls   

 

Port Side

TV antenna
Red  Front bedroom 12 V 
Gray    Side lights
Brown Side lights
Blue Bedroom ceiling lights
Gray Bathroom ceiling lights
Violet Bedroom and bathroom emergency ceiling lights
Black red speakers
Blue (with black) Solar panel

 

Main Hull Panels to Bridge Control Panel

The control wire consists of nine black wires numbered from 1 to 9 and a yellow-green wire, currently not used.

The wire #1 monitors the voltage of the service batteries on that side, while the others, always in pairs, monitor the amperages.

# 1 +12 V
# 2 - 3 Total load A
# 4 - 5 Battery charger A
# 6 - 7 Solar panels A
# 8 - 9 Alternator A

 

Light-Switch Wires

Forward.  Two 9 strand wires plus ground go from the light relay box behind the DC panel on the bridge a the small yellow junction box in the ceiling of the hallway.  Caution, just before the yellow box the two cables are joined to two multicolored cables that emerge in the yellow box, which is just a junction box, situated towards the bow of the box with the switches. 

From that box two multicolored cables go to:

 

Port Bathroom and Bedroom

Port bedroom 1 Blue
Port bedroom 2 Gray
Port bathroom 1 Green
Port bathroom 2 Brown
Port bedroom emergency White
Forward hall Black

 

Starboard Bedroom and Bathroom

Starboard bedroom 1 Black
Starboard bedroom 2 White
Starboard bathroom 1 Yellow
Starboard bathroom 2 Green
Starboard bedroom emergency Gray
Forward hall Red
Forward hall emergency Pink

 

Hallway

Forward hall Red
Forward hall emergency Pink
Port Gray
Starboard Yellow

 

The wire for controlling the aft lights is a multistranded wire with 6 numbered black wires.

Kitchen, Dinette and Outside Aft

Hall # 1
Kitchen # 2
Dinette # 3
Emergency # 4


 

Bridge

Starboard side, below bridge floor.  Starting from the front.

Windshield wipers
Radio box

Solar panels
Bridge and outside lights
Bridge speakers
Dinette and kitchen lights
Radar arch (big, white conduit)
Radar arch (big, white conduit)
Aft lights
Empty conduit for fuel pipe

Port side, below bridge floor.  Starting from the front.

Power receptacles
Windshield wipers
Solar panels
Bridge speakers
Dinette and kitchen lights
Radar arch (big, black conduit)
Radar arch (big, black conduit)
Aft door switches

Starboard side, below ceiling

From the circuit box above the     closet a white cable with 3 wires (brown, white, blue + ground (shield)) goes to the ceiling above the instrument panel.


Radar Arch 

Wires that go through the space behind the top aft of the side panels.

Starboard Side  Electrical

Blue, big   Navigation lights
Blue, big   Anchor light
Blue, big     Spreader lights
Brown   Search light
Brown   Horn
Red, big   + 12 V

Spreader and search lights could be inverted.

 

 Starboard Side  Electronics

     
Red
Yellow    
Ground      
NC    
Red    
Yellow    
ground    
ground    

 

 

 

Panel Location

Panel and junction boxes locations under the bridge.  Top is towards the bow.

 

DC Branch panel 1   DC Branch panel 1

 

DC Source selection panel   AC Branch panel 1

 

DC Branch panel 2   DC Branch panel 2

 

Engine DC battery charger   AC Source selection panel 

 

DC battery charger   AC Branch panel 2 or bus panel

 

     

 

DC - AC inverter   Computer netcards box

 

Computer netcards box   ZF Mathers box

 

    Autopilot box

 

Negative circuits Isolation Values

Wires that go through the space behind the top aft of the side panels.

Starboard Side  Electrical

4 strip for radar arch 235 kOhm
   
   
     
   
   
   

 

2016-06-05
cat_48_e dc electric layout.htm