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Electrical Load Calculation

Online Interactive Residential Electrical Load Calculator

residential-electrical-panel-calculations Summary: Residential Electrical Load Calculator, Online and Interactive provides accurate panel load calculations.

Quick Start Guide for the Electrical Load Calculator
Let's get started. Advanced
Experienced Electricians
No explanation needed.
Review the basics. Intermediate
Inspectors and Teachers
Short Explanations to help you get started.
Please explain the process. Novice
Homeowners and Students
Detailed explanations to help you get it right.

Please Note: This online calculating tool requires javascript to be turned on in your browser.

Detailed Instructions for the Electrical Load Calculator.

Introduction to the Electrical Load calculator

The purpose of the residential electrical load calculation is to accurately determine the size of the electrical service base upon the electrical equipment that will be installed. The national electrical codes are the basis of making sure the electrical service is sized properly and installed correctly.

Step 1

The General Electrical Load Requirements are based on the inside square feet area of the home which is then used to calculate the basic lighting load and required appliance circuits. The Residential Electrical Load Calculator is Pre-Loaded with electrical information for you to chose from. Click on the Question Mark Buttons for more specific information relating to each section and entry.

Step 2

Appliances and Motor Type Loads are typically larger equipment used in the kitchen, laundry room, garage. Be sure to check the nameplate information for accurate calculations.

Step 3

Heating and Air Conditioning. Properly Identifying Heating and Air Conditioning Equipment is very important because the equipment typically requires a larger electrical load.

Step 4

Perform the Calculations: The Calculate button will perform calculations from the information you have provided in this form. The Calculate Button Must Be Pressed when any changes are made to the form.

The Basics of How Electrical Power is Measured and Calculated

What is VA?

VA is the abbreviation for volt-ampere, which is a unit of power that is determined by multiplying the voltage and the amperage current in a circuit. VA is a standard measurement of electrical power that is used for identifying electrical circuit component requirements.
Example: a 120 volt circuit which is providing 1 ampere = 120 volt-amperes.

The Difference Between VA and Watts?

A watt is a measure of true power which is required to perform work at the rate of 1 joule per second. The wattage is calculated by multiplying voltage times the power factor of the circuit.
Example: Watts = Voltage times the Amperage times the Power Factor.

What is Power Factor?

PF or Power Factor is the ratio of the actual power in watts to the apparent power in volt-amperes which is expressed as a percentage.
Example: 100% power factor is the best , however a typical power factor could range between 75 to 90%.

In some areas of the form below you can combine VA loads for multiple equipment with the specified section.

Brief Instructions for the Electrical Load Calculator

The load calculator is divided into three main sections which enable you to enter the necessary information about the home project and the proposed electrical equipment that will be installed.

The calculations conform to the national electrical codes which focus on required loads and factoring in the appliance and motor equipment. The question mark help buttons will assist you with detailed information about typical equipment loads which may be selected in the various drop down menus.

This Residential Electrical Load Calculator is Pre-Loaded with electrical information for you to chose from. Please use additional Question Mark Buttons for more specific information. For your continuance the Update and Calculate Buttons will Recalculate the entire form.

Residential Electrical Load Calculator for Main Service

Step #1 - General Electrical Load Requirements    
Indoor Sq. Ft. Area of the Home
Small Appliance Circuits 1500VA Ea.
Laundry Circuit 1500VA Ea.
Sec. #1 Sub-Total =

Step #2 - Appliance & Motor Loads VA    
Cooktop Stove or Range  
Water Heater  
Other Additional Appliance(s)  
Sec. #2 Sub-Total =
First 10,000 VA @ 100% =
Adjustment 40% of Remainder =

Step #3 - Heating & Air Conditioning VA    
Single Source Heating Unit    
OR Air Conditioning and Heating Unit  
OR Heat Pump - No Supplemental Heat  
OR Continuous Electric Thermal Storage  
Heating Unit with Supplemental Heat Source    
OR Heat Pump  
Sup. Elect Heat OR Central Elect.Heat  
OR Space Heaters VA  
How Many Space Heaters  
Sec. #3 Sub-Total =

Step #4 - Perform the Calculations  
Calculated Total VA Load =
Calculated Total Amps Load =
Reset the Form

© Copyright Dave Rongey Ask-The-Electrician.com

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IMPORTANT: We provide these calculating tools as a guide to assist you to understand the process of accurately sizing a residential electrical panel based on proposed loads. The results of the calculations are based upon the accuracy of the information that you provide. The [Calculate] Button must be pressed when any changes are made to the form. Accurate load sizing is best performed by a professional architect or engineer which is reviewed by the building department in your jurisdiction.

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