About
This app calculates DC power lead sizes for telephone company central office power plants. It uses a circular slide rule format to determine allowable voltage drops and wire sizes based on specific system parameters.
What's New in leaDCalc
27.2
October 27, 2026
Version 27.2 Update new for iPhone Duo, otherwise same old great power lead calculator.
Developer apps
FAQ
What is leaDCalc used for?
leaDCalc is used to calculate DC power lead sizes and allowable voltage drops specifically for telephone company central office direct current power plants and distribution wiring. It's based on the original Bell System Lead Calculator.
What DC voltages does leaDCalc support?
The application references 48-volt battery systems but also works for other direct current voltages such as 24 volts. When using for other voltages, you select by the required loop voltage drop instead of the specific section of the circuit.
How does leaDCalc calculate wire size?
The formula used in lead size calculations is CM = LoopLength * 11.1 * Fuse or Breaker @ 100% / VD. The app also references variations used by T-Mobile and the Bell System, which may use percentages of the input breaker or fuse size.
Is leaDCalc affiliated with T-Mobile or the Bell System?
No, leaDCalc explicitly states it is NOT affiliated with any person, company, or entity, including T-Mobile or the Bell System. It is meant as a guide based on historical calculations.
What is the age rating for leaDCalc?
leaDCalc has an age rating of '4+' and is suitable for a wide range of users.
How often is leaDCalc updated?
The latest version, 27.2, was last updated on October 27, 2026. This indicates a history of updates, though the specific frequency is not detailed.
What devices can I use leaDCalc on?
leaDCalc is available for iPhone and iPad devices.
Does leaDCalc have ads?
No, leaDCalc does not contain advertisements.
