About this app
Adiabatic Equation for calculating the minimum cpc (circuit protective conductor) and earth minimum csa sizes of earthing conductors, S = √(I²t) / k. This Adiabatic Equation Calculator takes into account the following parameters: t = Disconnection time (seconds). k = Conductor k value (From BS 7671 tables). la = Fault current (PEFC in Amps). I² = la x la. Results with the minimum CSA mm². Values of K are obtained from the tables within BS 7671: - Table 54.2 : Conductor not incorporated in a cable and not bunched with cables. - Table 54.3 : Conductor incorporated in a cable or bunched with cables. - Table 54.4 : Sheath or armour of a cable. - Table 54.5 : Steel conduit or trunking. Disconnection times (t) are obtained from the maximum operating time/current characteristics tables within BS 7671: - Fig 3A2 (a,b) : BS 3036 semi-enclosed fuse. - Fig 3A3 : (a,b) : BS 88-2.2. - Fig 3A4 : BS EN 60898 / 61009-1 MCB/RCBO type B. - Fig 3A5 : BS EN 60898 / 61009-1 MCB/RCBO type C. - Fig 3A6 : BS EN 60898 / 61009-1 MCB/RCBO type D. - BS 1361 Fuse. How to use the Adiabatic Equation App: 1) Input your voltage value. 2) Input your Zs value. 3) Select protective device. 4) Select protective device rating. 5) Select conductor type. 6) Select conductor material. 7) Tap calculate.
Latest release
What’s New
30/07/2025 v2.1.5 - App optimisations. - UI improvements.
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Aug 10, 2026 · 4:36 PM $7.99
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