Blue Sea Systems 8120 Quick Start Manual

Marine Electrical Products
DC Power Distribution Panel

Panel Specifications

Material 0.125" 5052-H32 aluminum alloy
Final Panel Finish Graphite color 2 part textured Polyurethane
Circuit Breakers 15A single pole
Maximum Amperage Varies by components; busbar maximum 100A
Voltage Rating 12V DC
USB Charger 12/24V DC Dual USB 4.8A with intelligent
device recognition (1045)
Socket 12V DC Dash Socket 15A with watertight cap (1011)
Inches
Overall Dimensions 7.50 x 5.25
Mounting Centers 6.67 x 4.42

Applicable Standards

• American Boat and Yacht Council (ABYC) Standards and Recommended
Practices for Small Craft sections: E-1, E-3, E-9.
• United States Coast Guard 33 CFR Sub Part 1, Electrical Systems.

Installation

1. Disconnect all AC and DC power
Before starting, disconnect the main positive cable from all batteries to
eliminate the possibility of a short circuit while installing the distribution
panel. Also disconnect the AC shore power cord from the boat to
eliminate the possibility of electrocution from AC wiring in the proximity
of the DC distribution panel.
2.

Select mounting location and cut opening

Select a mounting location which is protected from water on the panel
front and back and is not in an area where flammable vapors from
propane, gasoline or lead acid batteries accumulate. The circuit
breakers used in marine electrical panels are not ignition protected and
may ignite such vapors.
Using the panel template provided, make a cutout in the mounting
surface where the distribution panel is to be mounted. Do not yet
fasten the panel to the mounting surface.
3.

Install positive feed wire and negative return

Determine the positive feed (red) and negative return (black or yellow)
wire size by calculating the total amperage of the circuits that will be
routed through the panel. Blue Sea Systems electrical panels are
rated at 100A total capacity. The positive feed wire must be sized
for 3% voltage drop at the 100A panel rating or the maximum
amperage that will be routed through the panel in any particular
installation, whichever is less. It is recommended that the positive feed
wire be sized for the full panel capacity, which, in most cases, will
require at least 2 AWG wire, assuming a 10 foot wire run between the
panel and the batteries in 12V systems. Refer to the Wire Sizing
Chart for other situations. Remember that the length of the circuit is the
total of the positive wire from the power source and the negative wire
back to the DC Negative Bus. Be certain that there is a fuse or circuit
breaker of the correct size protecting the positive feed wire.
8120
Millimeters
190.5 x 133.4
169.4 x 112.3
980037690 Rev.001
WARNING
These instructions are intended to provide assistance with the
installation of this product, and are not a substitute for a more
comprehensive understanding of electrical systems. We strongly
recommend that a competent electrical professional perform the
installation of this product.
If either the panel front or back is to be exposed to water it must be
protected with a waterproof shield.
The panels must not be installed in explosive environments such as
gasoline engine rooms or battery compartments as the circuit breakers
are not ignition protected.
The main positive connection must be disconnected at the battery post
to avoid the possibility of a short circuit during the installation of this
distribution panel.

Guarantee

Any Blue Sea Systems product with which a customer is not satisfied
may be returned for a refund or replacement at any time.

Useful Reference Books

• Calder, Nigel (2005). Boatowner's Mechanical and Electrical Manual
(3d ed). Camden, ME: International Marine / McGraw-Hill.
• Wing, Charlie (2006). Boatowner's Illustrated Electrical Handbook
(2d ed). Camden, ME: International Marine / McGraw-Hill.
Blue Sea Systems, Inc.
4600 Ryzex Way
Bellingham, WA 98226 USA
p 360.738.8230
bluesea.com
4.

Install branch circuit wires

Determine the proper wire size for each branch circuit using the
guidelines in step 4. Verify that the standard 15A circuit breakers
installed in the panel are large enough for each branch circuit. Remove
and replace with a higher amperage any that are undersized.
Connect the positive (red) branch circuit wires to the load terminals of
each circuit breaker.
Connect each negative (black or yellow) branch circuit wire to the DC
Negative Bus. DO NOT CONFUSE THE DC NEGATIVE BUS WITH
THE DC GROUNDING BUS.
5.

Installation of Backlight System

Connect the yellow negative wire to the panel negative bus.
To activate the label lights by the boat's battery switch, connect the red
positive wire to the DC panel positive bus.
To activate the label lights by an independent switch or breaker,
connect the red positive wire to the load side of the switch or breaker.
6.

Optional - install grounding system wire

The grounding wire (bare, green or green with yellow stripe and
normally non-current carrying) should not be confused with the
negative ground wire (black or yellow and normally current carrying).
In Boatowner's Illustrated Electrical Handbook, Charlie Wing identifies
three purposes of DC Grounding:
1. Holding conductive housings of low voltage (under 50 volts)
DC devices at ground potential by providing a low resistance
return path for currents accidentally coming into contact with the
device cases.
2. Providing a low resistance return path for electrical current,
preventing stray currents that may cause corrosion.