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.
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.
- Calculate available fault current
- Size fuses and conductors
- Generate service equipment labels
- Single and three-phase system support
- NEC® 110.24 compliance
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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
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.
- Conductor sizing
- Voltage drop limitations
- Circuit protection sizing
- Race sizing
- Equipment grounding conductor sizing
- Dwelling-unit service calculations
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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
Verdict
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
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.
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.
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.
| Parameter | Fault Current Calculator | Mike Holt's Electrical Toolbox |
|---|---|---|
| Price | Free | Free |
| Rating | 3.1 (23 ratings) | 4.6 (197 ratings) — better |
| Positive reviews | 0.0% of reviews | 76.7% of reviews — better |
| Number of ratings | 23 | 197 — better |
| Update frequency | Every 4 months | Every 3 months — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Freemium | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 14.0 | 14.0 |
| Further details — not scored | ||
| Size | 25 MB | 26 MB |
| Age rating | 17+ | 4+ |
| Developer | Cooper Bussmann, LLC | Mike Holt Enterprises |
Customer experience
Fault Current Calculator
Mike Holt's Electrical Toolbox
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
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- Add more features, willing to pay extra
In-app purchases
Fault Current Calculator
- Pro Monthly Subscription7 Days trial$4.991 Month
- Pro Annual Subscription7 Days trial$39.991 Year
Mike Holt's Electrical Toolbox
No in-app purchases
Questions
Is Fault Current Calculator free?
Is Mike Holt's Electrical Toolbox free?
Which has better reviews, Fault Current Calculator or Mike Holt's Electrical Toolbox?
Do Fault Current Calculator or Mike Holt's Electrical Toolbox have ads?
Which is updated more often, Fault Current Calculator or Mike Holt's Electrical Toolbox?
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