ASSAM ENGINEERING INSTITUTE
DEPARTMENT OF ELECTRICAL ENGINEERING
GUEST LECTURE
REPORT ON
“Guidelines of Electrical Load Calculations”
Guest Lecturer: Utpal Prasad Das
Date: 15th March 2024
Submitted By-
Name: Hriday Ranjan Deka
Semester: 4th
Roll No. AEI/22/EL/028
Branch: Electrical Engineering
Activity: Guest Lecture
CONTENTS
About Electrical Load
Different types of Electrical Load
Guidelines
Conclusion
About Electrical Load
The device which takes electrical energy is known as the electric load. In
other words, the electrical load is a device that consumes electrical energy
in the form of the current and transforms it into other forms like heat,
light, work, etc. The electrical load may be resistive, inductive, capacitive
or some combination between them. The term load is used in the number
of ways.
To indicates a device or a collection of the equipment which use electrical
energy.
For showing the power requires from a given supply circuit.
The electrical load indicates the current or power passing through the line
or machine.
Types of Electrical Loads
The nature of the load depends on the load factor, demand factor, diversity
factor, power factor, and a utilisation factor of the system. The different types of load
are explained below in details.
Resistive Load
The resistive load obstructs the flow of electrical energy in the circuit and converts it
into thermal energy, due to which the energy dropout occurs in the circuit. The lamp
and the heater are the examples of the resistive load. The resistive loads take power in
such a way so that the current and the voltage wave remain in the same phase. Thus the
power factor of the resistive load remains in unity.
Inductive load
The inductive loads use the magnetic field for doing the
work. The transformers, generators, motor are the examples of the load. The inductive
load has a coil which stores magnetic energy when the current pass through it. The
current wave of the inductive load is lagging behind the voltage wave, and the power
factor of the inductive load is also lagging.
Capacitive Load
In the capacitive load, the voltage wave is leading the current wave. The examples of
capacitive loads are capacitor bank, three phase induction motor starting circuit, etc.
The power factor of such type of loads is leading.
Types of Electrical Loads in Power System
The total loads of an area depend on its population and living standard of the people.
The different types of the loads in a power system are as follows.
1. Domestic load
2. Commercial load
3. Industrial load
4. Agriculture load
Domestic Load – The domestic load is defined as the total energy consumed by
the electrical appliances in the household work. It depends on the living
standard, weather and type of residence. The domestic loads mainly consist of
lights, fan, refrigerator, air conditioners, mixer, grinder, heater, ovens, small
pumping, motor, etc. The domestic load consume very little power and also
independent from frequency. This load largely consists of lighting, cooling or
heating.
Commercial Load – Commercial load mainly consist of lightning of shops, offices,
advertisements, etc., Fans, Heating, Air conditioning and many other electrical
appliances used in establishments such as market restaurants, etc. are considered as a
commercial load.
Industrial Loads – Industrial load consists of small-scale industries, medium scale
industries, large scale industries, heavy industries and cottage industries. The induction
motor forms a high proportion of the composite load. The industrial loads are the
composite load. The composite load is a function of frequency and voltage and its form a
major part of the system load.
Agriculture Loads – This type of load is mainly motor pumps-sets load for irrigation
purposes. The load factor of this load is very small e.g. 0.15 – 0.20.
Guidelines of Electrical Load Calculations
How To Calculate Electrical Load
To determine the feasibility of adding a new large appliance to your electrical system
without upgrading the panel, you need to calculate the load your current system draws.
Electricians have a simple formula for this. But master electrician John Williamson — the
retired chief electrical inspector for the Minnesota Department of Labor and Industry —
says this isn’t how the NEC calculates load. However, because the NEC method is too
complicated for most homeowners, it’s a good approximation.
1. Using the exterior dimensions of your home, calculate the approximate square
footage, including attached garages. Exclude open porches and unfinished areas not
adaptable for future habitable use.
2. Determine the power draw for all your general lighting and receptacle circuits, as
well as circuits supplying major appliances.
3. Include 1,500 volt-amperes for each 120-volt 20-amp kitchen circuit, and likewise for
a 20-amp laundry circuit.
4. Add the power rating (in volt-amperes) for all appliances fastened in place,
permanently connected or on dedicated circuits, like your washer/dryer, dishwasher,
electric stove, microwave, refrigerator and water heater. Get the rating by reading
the label on the appliance, or by checking the product specs online. If the label
specifies current draw, multiply that by the operating voltage (either 120 or 240
volts, depending on the size of the unit) to get the power rating in watts.
Note: If you’re doing this calculation to determine whether your panel can handle a
new appliance like a water heater, add the wattage of that appliance here.
5. Check the labels on your furnace and air conditioning system for their power ratings.
Because you won’t ever use these appliances together, choose the larger number
and add it to the total.
Conclusion
Calculating electric load is crucial when building a home for several
reasons. First, it ensures that our electrical system can handle the total
demand of electricity required by our home. An electrical load is any
electrical device or component that consumes electrical energy and
converts that energy into another form. As part of any electrical circuit,
the component transforms current into something useful, commonly
motion, light, or heat.
