Calculations

The articles in this section explain how different calculations work or provide additional context to calculation-related concepts in Design Master Electrical.

📄️ Sizing Branch Circuits for Continuous & Noncontinuous Load Types

Design Master Electrical considers some load types as continuous and others as noncontinuous when sizing branch circuits in accordance with the NEC. This article specifies how each load type is used, and how the sizing can be customized.

📄️ Motor Load Calculations

How the Single Motor and Multiple Motors load types are used for motors in Design Master Electrical.

📄️ Arc-Flash Overview

A brief look at how to calculate arc-flash, display the calculations on the drawing, and print stickers to place on distribution equipment.

📄️ Feeder and Service Load Calculations

The calculation methods available in the Feeder and Service Calculation Settings dialog box, and how to correctly model your loads for each using relevant NEC references.

📄️ Lighting Calculations

Lighting loads can be calculated as continuous loads or as a general lighting load, for which the calculation is dependent upon the occupancy area and demand.

📄️ Electrical Load Type Explanations

This article describes the load types available in Design Master Electrical and how they should be used.

📄️ Loads on Phases Change or Rotate in a Transformer

If the per-phase loads on your transformer do not match loads on the connected panel, a phase shift may be the reason.

📄️ Residential Feeder Load Calculation Quick Start

This is the workflow we recommend for setting residential feeder loads in your project.

📄️ Arc-Flash Trip Times

You can select a breaker or enter a trip time manually to calculate arc-flash values. If you don't have that information, here is a way you can estimate the trip time.

📄️ Showing Voltage Drop on the First Panel

You can set a voltage drop on the first panel in a project by connecting it to an upstream panel that is set to not be shown on the voltage drop schedule.

📄️ Transformer Losses in Upstream Panels

To show transformer loss on panels, you must calculate the loss manually and enter it as a custom load on the transformer.

📄️ Voltage Drop and Transformers Options

Design Master Electrical offers three options for how to calculate voltage drop at transformers.

📄️ Reading and Configuring Time-Current Curves

A brief explanation of what each part of the time-current curve represents and how you can make changes to the curve.

📄️ Electrode Configurations for Arc-Flash Calculations

This article will help you determine the electrode configuration for your distribution equipment, in order to perform arc-flash calculations.

📄️ Room Data and Photometrics Show Different Foot-candle Values

Different values for room and point-by-point foot-candle calculations are a result of different calculation methods.

📄️ Arc-Flash Settings and Sensitivity (IEEE Std 1584-2018)

There are several factors that can influence arc-flash calculations, such as the working distance and the electrode configuration.

📄️ Required PPE Not Included in Arc-Flash Schedule

PPE requirements are not included in arc-flash schedules based upon guidance from NFPA 70E.

📄️ How Building Angle Affects Calculations

The Building Angle setting offsets the axes along which wire length calculations are performed, which can significantly impact several figures in your project.

📄️ NEC 220.55 for Single-Phase Ranges and Three-Phase Service

Load calculations for NEC 220.55 can be complex. Use these steps to backcheck the Design Master Electrical calculations for single-phase ranges on a three-phase service.