Comparison

Fault Current Calculator vs Mike Holt's Electrical Toolbox

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Fault Current Calculator

This tool helps contractors, engineers, and electricians quickly calculate available fault current on single and three-phase electrical systems. It also assists in sizing fuses and conductors for various circuits and can generate labels for service equipment.

Highlights
  • Calculate available fault current
  • Size fuses and conductors
  • Generate service equipment labels
  • Single and three-phase system support
  • NEC® 110.24 compliance
Features
Read full description

Eaton's Bussmann Series FC2 Available Fault Current Calculator application is an innovative tool developed for contractors, engineers, electricians, and electrical inspectors. This tool can be used on the Bussmann website or out in the field on a mobile device for those needing a quick and simple way to determine available fault current. With this simple tool, users can: - Calculate available fault current on single and three-phase systems - Create and send a label via email for marking the available fault current on service equipment (NEC® 110.24) - Size fuses and conductors for service, feeder, and branch circuits. This application, calculations, and other information are intended to clearly present technical information that will determine the available fault current at specific points in an electrical system. Bussmann reserves the right, without notice, to change this application and/or discontinue/ limit its distribution and/or availability. Bussmann also reserves the right to change or update, without notice, any technical information contained in this application. The data and information presented in this application are believed to be accurate. However, any and all liability for the content, or any omissions from this application, including any inaccuracies, errors, or misstatements in such data, calculations or information, is expressly disclaimed. The application, calculations and other information are provided without warranty of any kind, either expressed or implied, but not limited to, the implied warranties of merchantability, or fitness for a particular purpose. Bussmann disclaims any liability for the use of this application, calculations or other information. The complete End-User License Agreement can be found at: https://faultcurrentcalculatorpro.bussmann.com/home/eula

About

Mike Holt's Electrical Toolbox

This app provides essential calculations for electricians, inspectors, contractors, and engineers. It helps determine conductor sizing, circuit protection, race sizing, and grounding conductor sizes for various electrical equipment and services.

Highlights
  • Conductor sizing
  • Voltage drop limitations
  • Circuit protection sizing
  • Race sizing
  • Equipment grounding conductor sizing
  • Dwelling-unit service calculations
Features
Read full description

Mike Holt, the industry leader in the electrical industry (MikeHolt.com) has created an amazing, practical and useful app for the electrician, inspector, instructor, contractor and engineer. The app contains conductor sizing (including voltage drop limitations), circuit protection sizing, race sizing, equipment grounding conductor sizing for electric heating equipment (commercial and Residential), air-conditioning equipment (commercial and Residential), motors (commercial and Residential), Transformers (commercial) , and dwelling-unit service calculations and sizing.

Screenshots

Fault Current Calculator4 screens
Mike Holt's Electrical Toolbox4 screens

Verdict

The call

The clearest difference is review sentiment: Mike Holt's Electrical Toolbox at 77% against Fault Current Calculator's 0%. Mike Holt's Electrical Toolbox also leads on rating (4.6 vs 3.1) and in-app purchases (none vs 2). On price, update cadence, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Fault Current Calculator sells 2 in-app purchases, starting at $4.99 per month. Mike Holt's Electrical Toolbox asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Mike Holt's Electrical Toolbox holds the better App Store score, 4.6 against 3.1. That said, the two scores are not equally well evidenced: Mike Holt's Electrical Toolbox has 197 ratings behind it against 23, so its average is the more settled of the two. Written reviews point the same way: 0% of Fault Current Calculator's written reviews are positive against 77% of Mike Holt's Electrical Toolbox's.

UpkeepUpdate frequency

Fault Current Calculator ships an update every 4 months, Mike Holt's Electrical Toolbox every 3 months. The most recent releases landed on August 20, 2026 and September 21, 2026 respectively.

Scorecard5 real differences · 5 level
Fault Current Calculator versus Mike Holt's Electrical Toolbox: the parameters behind the verdict, then further details
ParameterFault Current CalculatorMike Holt's Electrical Toolbox
PriceFreeFree
Rating3.1 (23 ratings)4.6 (197 ratings) — better
Positive reviews0.0% of reviews76.7% of reviews — better
Number of ratings23197 — better
Update frequencyEvery 4 monthsEvery 3 months — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemiumFree — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS14.014.0
Further details — not scored
Size25 MB26 MB
Age rating17+4+
DeveloperCooper Bussmann, LLCMike Holt Enterprises

Customer experience

Fault Current Calculator

All ratings23 ratings
Positive47.8%
Neutral8.7%
Negative43.5%
Written reviews10 reviews
Positive0.0%
Neutral20.0%
Negative80.0%

Mike Holt's Electrical Toolbox

All ratings197 ratings
Positive90.4%
Neutral1.5%
Negative8.1%
Written reviews30 reviews
Positive76.7%
Neutral6.7%
Negative16.7%

Bugs and requests

Fault Current Calculator

Not enough reviews yet to summarise bugs or requests.

Mike Holt's Electrical Toolbox

Reported bugs

4 issues
  • Cannot email results
  • Video player widescreen exit bug
  • Previous calculation data not erased
  • App content is outdated

Requested features

6 requests
  • Increase transformer capacity to 225kva
  • Add option to print load calc
  • Update to NEC 2020
  • Add completion system for video series
  • Refine user interface for better usability
Show 1 more
  • Add more features, willing to pay extra

In-app purchases

2 purchases

Fault Current Calculator

Subscriptions2
  • Pro Monthly Subscription7 Days trial$4.991 Month
  • Pro Annual Subscription7 Days trial$39.991 Year
None

Mike Holt's Electrical Toolbox

No in-app purchases

Questions

Is Fault Current Calculator free?
Fault Current Calculator is free to download, with in-app purchases available.
Is Mike Holt's Electrical Toolbox free?
Mike Holt's Electrical Toolbox is free to download, with no in-app purchases.
Which has better reviews, Fault Current Calculator or Mike Holt's Electrical Toolbox?
Mike Holt's Electrical Toolbox is rated higher. Fault Current Calculator averages 3.1 out of 5 from 23 ratings, while Mike Holt's Electrical Toolbox averages 4.6 from 197 ratings.
Do Fault Current Calculator or Mike Holt's Electrical Toolbox have ads?
Neither Fault Current Calculator nor Mike Holt's Electrical Toolbox shows ads.
Which is updated more often, Fault Current Calculator or Mike Holt's Electrical Toolbox?
Fault Current Calculator ships an update every 4 months, and Mike Holt's Electrical Toolbox every 3 months. Most recently, Fault Current Calculator was updated on August 20, 2026 and Mike Holt's Electrical Toolbox on September 21, 2026.

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