Design current with a diversity rule of thumb
Add the loads by kind and Lastsocket applies a classic domestic recipe to estimate the design current. The raw sum is shown beside it, and a toggle uses the raw sum instead.
Limits and citations come from the app's pack files. The calculator below is checked against the app's engine on every build · engine 1.
The same job in the app
45.7 A raw becomes 28.8 A after the recipe.
How it's calculated
Each load carries a tag, and each tag has its share of the recipe:
- Lighting: 66 %
- Cooking: 10 A + 30 % of the remainder
- Heating: 100 %
- Sockets: first 10 A + 40 % of the remainder
- Other: 100 %
The result is a current at the system voltage, ready to carry into the cable size or voltage drop calculator. The app labels it as a recipe rather than citing a clause, because it is one.
Worked example
500 W of lighting, 7000 W of cooking and 3000 W of sockets add up to 45.7 A; after the recipe the design current is 28.8 A.
What this does not check. Rule of thumb — not a substitute for the national diversity annex. Lastsocket is a design aid. It does not replace the applicable installation standard, manufacturer data, or a qualified person’s judgement. Sources and limits →
Free or Pro. Free. The recipe is fixed and printed on the screen.