Quick calculators and checklists for contractors and project engineers — no sign-up, no catch.
Build a whole low-voltage installation as a single-line diagram — supply, switchboard, distribution boards, sub-mains and final circuits — and calculate it all to BS 7671 in one pass: maximum demand rolls up, fault level and earth-loop Zs propagate down, cables auto-size, and discrimination and breaking capacity are checked between devices in series.
Open the designerConvert between power, current and kVA for DC, single-phase and three-phase circuits with power factor — updating as you type. Add a cable length for voltage drop and a suitable BS 7671 cable size: copper or aluminium, PVC/XLPE/SWA/flexible/MICC, methods A–G including buried. Motor mode, power-factor correction, live charts and a printable report.
Open the calculatorMEP support bracket assurance calculations. Draw an interconnected rod-and-Unistrut support network, roll loads up automatically and check every rod, fixing and bearer to BS 8519:2020 — then export an auditable, formula-visible Excel calculation.
Open the calculatorSize trunking, duct, tray, ladder and basket from a cable schedule — sum the cable areas or widths, apply the 45% space factor and future spare, and get the smallest passing size with a printable calculation report (IET GN1).
Open the calculatorUpload a PDF drawing, set the scale, outline the room or platform — and get a 1 m × 1 m measurement grid as an Excel recording sheet with live average, minimum, uniformity and Pass/Fail formulas, plus the marked-up drawing showing where every reading is taken. Mark obstructions and zones; a whole station in one file.
Open the generatorSize a room's lighting by the lumen method — enter the room, a BS EN 12464-1 lux target and a luminaire, and get the number of fittings, a to-scale layout grid, spacing, average lux and power density, with a printable calculation report.
Open the calculatorExactly what to gather before commissioning an earthing study, cable calculation pack or lighting design — printable, so you can hand it to the project team.
Open the checklistFree practice questions for the ECS Health, Safety & Environmental Assessment — learn each topic with instant explanations, or sit a timed 50-question mock exam against the 43/50 pass mark. Unofficial revision aid, no sign-up.
Start practisingOne distribution board, circuit by circuit — current-carrying capacity with derating, voltage drop, earth-fault loop Zs and the adiabatic CPC, with a printable report.
Open the calculatorProspective short-circuit current at a board from the transformer or a known supply, plus a cable run — checked against a device's breaking capacity.
Open the calculatorA board's loads with diversity → the maximum demand in amps and kVA, the three-phase balance, and a suggested incomer rating.
Open the calculatorTwo devices in series — MCB, RCBO or fuse → an indicative discrimination verdict. Fuse pairs on the BS 7671 Annex A53 ratio, RCDs on Reg 536.4.1.4.
Open the checkerMore tools are on the way — an earth electrode / EPR estimator is next. Need something more specialised? We build bespoke engineering tools & software to your project standards — cleat spacing, containment loading, trackers and more.