Tools
Calculators for the questions that come up on site. Free, no sign-up, and the working is shown rather than hidden, so you can check the answer rather than take it on trust.
- How big a board do I need?
Distribution board size calculator
Enter the MCBs, RCCBs, RCBOs and isolators going in. Get the module count, the rail width in millimetres, and the board size to order.
Open the calculator → - Is this run too long?
Voltage drop calculator
Enter the load, the run length and the conductor size. Get the drop in volts and as a percentage, checked against the 3% and 5% limits, with the working shown.
Open the calculator →
Looking for the reasoning rather than the arithmetic?
The technical guides cover how each decision is made: MCB curve selection, cable sizing, the difference between FR, FRLS and LSZH, and which IP rating an enclosure needs.