# Fault Current Calculator

> Calculates electrical fault current, sizes fuses/conductors, and generates equipment labels. (iPhone/iPad app by Cooper Bussmann, LLC.)

- Source: https://appshunter.io/ios/app/fault-current-calculator/id647477910 (this page in markdown: same URL + `.md`)
- Developer: [Cooper Bussmann, LLC](https://appshunter.io/developer/609315535)
- Category: Utilities
- Price: Free with in-app purchases
- Rating: 3.10/5 from 23 App Store ratings · 10 written reviews indexed
- Age rating: 17+
- Requires: iOS 14.0 · 25 MB
- Languages: American English
- Released: 2013-05-21
- Data updated: 2026-08-20
- Monetization: freemium
- User reviews in markdown: https://appshunter.io/ios/app/fault-current-calculator/id647477910/reviews.md

## What is Fault Current Calculator?

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

## Key features

- Calculate available fault current
- Size fuses and conductors
- Generate service equipment labels
- Single and three-phase system support
- NEC® 110.24 compliance

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Pro Monthly Subscription | $4.99 | per month |
| Pro Annual Subscription | $39.99 | per year |


## Recent user reviews (10 of 10)

All indexed reviews: https://appshunter.io/ios/app/fault-current-calculator/id647477910/reviews.md

### 1/5 — Stuck in update

*2025-07-17*

Used to work great- forced to pay for the upgraded version that doesn’t work.  Its stuck in the spinning wheel of updating

### 1/5 — Can’t even open the app

*2025-06-17*

Stuck on a black screen, please update

### 1/5 — Could be 5 star

*2025-06-13*

This app secretly updated itself to a pro version which I am not paying for. I can no longer download the standard version.

### 2/5 — Basically it’s a label creator

*2023-03-02*

Basically it’s a label creator,  kinda silly and poorly designed.

### 3/5 — Two issues

*2018-10-08*

Will not allow selection of 10kVA transformer. Will not email labels with iOS 12.
For my use, these are small problems that if fixed would garner the app 5 stars from me.

### 1/5 — Bussmann fault app

*2018-10-05*

This app does not work with the new iOS upgrade that Apple just put out to their phones, especially their older phones I agree with the previous review need to get this corrected!

### 1/5 — Doesn’t work on ios12

*2018-10-05*

Display and keyboard is all messed up in iOS 12

### 1/5 — Broken for iOS 12

*2018-09-26*

Will not work for iOS 12. Needs an update.

### 1/5 — App doesn’t work anymore

*2018-09-25*

I used this app for a couple of years, worked great. Got new phone and ios12 now the app doesn’t work.

### 3/5 — Amazing app with two (significant) flaws

*2018-03-14*

This app is free, and saves an incredible amount of time. It would garner 5 stars, except for two significant flaws: Firstly, you can only map one branch at a time, which means mapping a system with multiple branches requires you to restart for each branch. 

Secondly, and most importantly, hitting the home button completely resets your progress. This makes the app almost unusable; if you stop to take a call or text, you have to start over. If this glaring issue was fixed, 4-5 stars would be warranted. On the other hand, this app also exists on Bussmann’s website, without this issue. For the time being, I recommend using the app there.

## Frequently asked questions about Fault Current Calculator

### What is Fault Current Calculator used for?

Fault Current Calculator is used to determine the available fault current on single and three-phase electrical systems. It also assists in sizing fuses and conductors for service, feeder, and branch circuits, and can generate labels for service equipment.

### Is Fault Current Calculator free to use?

The basic version of Fault Current Calculator is free to download and use. However, it offers optional Pro subscription plans for enhanced features, with a 7-day free trial available for both monthly and annual subscriptions.

### What are the subscription options for Fault Current Calculator?

Fault Current Calculator offers a Pro Monthly Subscription for $4.99 per month and a Pro Annual Subscription for $39.99 per year. Both plans include a 7-day free trial.

### What devices does Fault Current Calculator support?

Fault Current Calculator is supported on iPhone, iPad, and iPod devices. It is designed for mobile use in the field or on the go.

### How often is Fault Current Calculator updated?

The latest version of Fault Current Calculator is 4.2.1, last updated on September 17, 2025. Updates are released periodically to improve functionality and technical information.

### What is the age rating for Fault Current Calculator?

Fault Current Calculator has an age rating of 17+. This is likely due to the technical nature of the calculations and information provided, which is intended for professional use.

### Does Fault Current Calculator have ads?

No, Fault Current Calculator does not contain advertisements. The application is free to use, with optional in-app purchases for premium subscription features.

### Where can I find the End-User License Agreement for Fault Current Calculator?

The complete End-User License Agreement for Fault Current Calculator can be found at https://faultcurrentcalculatorpro.bussmann.com/home/eula. It outlines the terms of use and disclaimers.

## Version history (last 5 releases)

### 4.2.1 — 2025-09-17

We’ve made several behind-the-scenes improvements to enhance the user experience:
- Smoother navigation for a streamlined sign-up process

- Minor bug fixes to keep things running reliably
- Small design tweaks for a cleaner, more intuitive interface


Update now to enjoy a more seamless FC2 experience!

### 4.2.0 — 2025-06-06

Users now have two options to choose from, the Standard or Pro version. 

The Standard version is free for all users and provides essential tools and functionalities, including: 
- Create one-line diagrams 
- Perform basic fault current calculations 
- Send calculations to the registered email only 
- Generate up to 4 PDF files of available fault current calculations per day 
- Handle transformer sizes up to 5 MVA

For a more comprehensive solution, the Pro version offers everything in the standard version plus advance features including:
- Send calculations to ANY email address
- Generate UNLIMITED PDF file of available fault current calculations
- Handle transformer sizes up to 10 MVA
- Save and edit diagrams
- Edit and mange projects
- Simplified component modification to add, delete, and edit components
- Add generator to the system
- Set default transformer value (from previous selection) for a quick selection
- Add motor contributions for single phase system 
- Consolidate multiple project calculations in a single email

### 4.1.6 — 2022-07-08

User experience enhancements and bug fixes.

### 4.1.4 — 2020-05-07

Updated user interface.

### 4.1.3 — 2019-04-13

Updated the fuse sizing and user guide functions.

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## More apps by Cooper Bussmann, LLC

- [Eaton Bussmann Fuse Finder](https://appshunter.io/ios/app/eaton-bussmann-fuse-finder/id609315532)
- [Edison XRef](https://appshunter.io/ios/app/edison-xref/id1470236203)

All apps by Cooper Bussmann, LLC: https://appshunter.io/developer/609315535

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-20.*