E-22.214.171.124. FOR DC SYSTEMS
126.96.36.199.1. Conductors and flexible cords shall have a minimum rating of 50 volts.
188.8.131.52.2. The construction of insulated cables and conductors shall conform with the requirements of:
184.108.40.206.2.1. UL 1426, Cables for Boats, or 220.127.116.11.2.2. the insulating material temperature
rating requirements of: 18.104.22.168.2.2.1. SAE J378, Marine Engine
, and 22.214.171.124.2.2.2. SAE J1127, Battery Cable, or
SAE J1128, Low-Tension Primary Cable.
126.96.36.199.3. Conductors may be selected from the types listed in TABLE VI , Table VIII and TABLE IX . The temperature ratings shown contemplate the routing of wires above bilge
water in locations protected from dripping, exposures to weather
, spray, and oil
188.8.131.52.4. Flexible cords shall conform with the National Electrical
Code, and shall be selected from the types listed in Table VIII.
184.108.40.206.5. Conductors and flexible cords shall be stranded copper according to TABLE XII.
220.127.116.11.6. Conductors used for panelboard or switchboard main feeders shall have ampacities as determined in E-18.104.22.168 Conductors used for branch circuits or in electrical
systems that do not use a panelboard or switchboard shall have their ampacities determined by their loads (See TABLE II).
22.214.171.124.7. Conductors used for panelboard or switchboard main feeders, bilge blowers, electronic equipment
lights, and other circuits where voltage drop must be kept to a minimum, shall be sized for a voltage drop not to exceed three percent. Conductors used for lighting
, other than navigation
lights, and other circuits where voltage drop is not critical, shall be sized for a voltage drop not to exceed 10 percent.
126.96.36.199.8. To determine conductor size and insulation
temperature rating, use the ampacity as specified in E-188.8.131.52.6 in conjunction with TABLE IV . Then use TABLE X or TABLE XI to check the conductor size for compliance with the maximum allowable voltage drop specified in E-184.108.40.206.7. In the event of a conflict between the ampacity table and the voltage drop tables, the larger conductor size shall be used.
220.127.116.11.9. To use TABLE X and TABLE XI , measure the length of the conductor from the positive power source connection to the electrical device and back to the negative power source connection. Use the conductor length, the system voltage, and the ampacity as specified in E-18.104.22.168.6, in conjunction with the appropriate volt drop table, i.e., 3 percent or 10 percent – TABLE X or TABLE XI , to determine conductor size.
NOTES: 1. The power source connection may be the battery, or a panelboard or switchboard, if used.
2. If the ampacity as specified in E- 22.214.171.124.6 exceeds the ampacities in TABLE XI and TABLE X, the conductor size necessary to keep voltage drop below the maximum permitted level may be calculated by means of the following formula:
K x I x L
CM = —————
CM = Circular mil area of conductor.
K = (constant representing the resistivity of copper)
I = Load current
L = Length of conductor from the positive power source connection to the electrical device and back to the negative power source connection, measured in feet.
E = Maximum allowable voltage drop at load in volts (e.g., for a three percent voltage drop at nominal 12V, E= 0.03 x 12 = 0.36; for a 10 percent voltage drop at nominal 12V , E = 1.2).
3. Use TABLE XII to convert circular mils (cm) to conductor gauge. If the cm area falls between two gauge sizes, the larger conductor shall be used.