ABC AC Electrical Load Calculations





A. Lighting Fixtures and Receptacles - Length times width of living space (excludes spaces exclusively for machinery and open deck space) times 3 watts per square foot.
          Formula: Length x width x 3 = lighting watts

B. Small Appliances - Galley and Dinette Areas - Number of circuits times 1,500 watts for each 20 ampere appliance  receptacle circuit.
          Formula: Number of circuits x 1,500 = small appliance watts.


C. Total- Formula: Lighting watts + small appliance watts = ____ total watts.

D. Load Factor - Formula: First 3,000 watts at 100% =_________
                                       Remaining total watts x 35% =  _______
                                   Total watts by system voltage = ________ amperes

E. Lighting and small appliance current (amperes) for each leg
    as calculated in "D" above:
                                                                       Leg A            Leg B
                                                                   ________         _________

F. Add nameplate amperes for motor and healer loads:
                             Exhaust and supply fans  _______          _______
                               Air conditioners*, **    _______         ________
                        Electric, gas or oil heaters* _______        _______
           25% of largest motor in above items  _____            _______


NOTE:
*Omit smaller of these two, except include any motor common to both functions.
* *If system consists of 3 or more independent units, adjust the total by multiplying by 75 % diversity factor

                                                     Sub-Total: ________     ________

G. Add nameplate amperes at indicated use factor percentage  for:
                                                                    Leg A               Leg B
                               Disposal 10%
               Water Heater       100%            ______       _________
         Wall-mounted Ovens 750%           _______     _________
                 Cooking units      75%          ________     _________
                  Refrigerator       100%        _________    _________
                     Freezer            100%           _______     _________
                    Ice Maker          50%            ________     _________
                  Dishwasher         25%           _______       ________
              Washing Machine    25%          _________    __________
                        Dryer              25%           ________      _________   
               Trash Compactor    10%           _________    _________
               Air Compressor     10%          ________     _________
                Battery Chargers 100%          ________    __________


                                                Subtotal: _______  ___________
                          **Adjusted Sub-Total: _______  ___________

NOTE:
*
*If four or more appliances are installed, adjust the total by multiplying by 75% diversity factor.

H. Add amperes for free standing range as distinguished from separate oven and cooking units as provided for in "G".  Derive from the following table by dividing watts by 125  volts or 250 volts depending on which unit is installed.


RANGE        NAMEPLATE WATTS          USE (WATTS)
                      10,000 or less                               80% of rating
                      10,00 1-12.500                               8.000
                      12,501- 13.500                              8.400
                      13,501- 14.500                              8.800
                      14,501- 15.500                              9. 200
                      15,501 16.500                               9.600
                      16,501-17.500                             10.000

                        Sub-Total: __________  ___________
I. Lighting and small appliances "E"
                          Motors "F"
                Fixed Appliances "G"
             Free Standing Range "H"
                                Total:    _________      _________


NOTE:
If the total for Legs A and B are unequal, use the larger Value to determine the total power required.

After performing the load calculations if you realize that it Is necessary to either split the system and balance the load or add an additional system to handle the air conditioning, it is a project that your boat dealer or service yard will be happy to do for you. MARINCO offers a complete line of marine electrical equipment that incorporates today's latest technical advances is practical, designed to last, and most importantly easy to install.

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