Electrical Engineering Calculators & PE Exam Prep
These tools are for electrical engineers and designers who work in metric units and IEC methods, and for anyone preparing for the PE Electrical and Computer: Power exam. The cable calculator sizes up to 50 low-voltage circuits by the IEC 60364-5-52 method for current and voltage drop. The solar workbook goes from a daily load table to PV strings, battery bank, charge controller and inverter. The panel schedule balances a 3-phase board and suggests circuit moves. A bundle includes all three workbooks. The PE Power pack is separate: three printable PDFs with a formula sheet, flashcards and original practice problems with final answers only.
The workbooks have no macros, and each shows its method on open sheets with a worked example. Scripts recalculate each file in LibreOffice and compare it with a separate Python calculation. They are estimation aids: check results against your local code and the equipment datasheets, and have a qualified engineer review the design.
All 5 templates
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IEC Cable Sizing + Voltage Drop Calculator
Size up to 50 IEC circuits for current and voltage drop, with OK / FAIL on every row
$5.69 on Etsy -
Off-Grid Solar + Battery Sizing Calculator
Go from a daily load list to PV array, battery bank, controller and inverter, with string checks
$5.69 on Etsy -
3-Phase Panel Schedule + Load Balancing Calculator
Schedule up to 60 circuits and get suggested moves that even out L1, L2 and L3
$5.69 on Etsy -
Electrical Design Calculator Bundle (3 workbooks)
Cable sizing, solar sizing and 3-phase panel balancing workbooks that work together
$13.59 on Etsy -
PE Power Exam Study Pack
Formula sheet, 98 flashcards and 21 problems with final answers
$7.89 on Etsy
Which one do I need?
| Template | Best for | Opens in | Files | Inside | Bundle contains | Price |
|---|---|---|---|---|---|---|
| IEC Cable Sizing + Voltage Drop Calculator | Sizing LV cables the IEC / metric way | Excel for Mac, LibreOffice | 1 .xlsx + example PDF | Up to 50 circuits, worked example, data sheet | — | $5.69 |
| Off-Grid Solar + Battery Sizing Calculator | Off-grid and hybrid solar with batteries | Excel for Mac, LibreOffice | 1 .xlsx + example PDF | Up to 40 loads, PV strings, battery, payback | — | $5.69 |
| 3-Phase Panel Schedule + Load Balancing Calculator | Balancing a 3-phase distribution board | Excel for Mac, LibreOffice | 1 .xlsx + example PDF | Up to 60 circuits, suggested moves, feeder size | — | $5.69 |
| Electrical Design Calculator Bundle (3 workbooks) | Board, cable and solar design together | Excel for Mac, LibreOffice | 3 .xlsx + 3 example PDFs | Cable, solar and 3-phase panel workbooks | IEC Cable Sizing + Voltage Drop Calculator, Off-Grid Solar + Battery Sizing Calculator, 3-Phase Panel Schedule + Load Balancing Calculator | $13.59 |
| PE Power Exam Study Pack | PE Power candidates who want a printable study set | — | 3 PDF files, US Letter | 4-page formula sheet, 98 cards, 21 problems, 1 answer page | — | $7.89 |
Prices in US dollars from our listing records. Etsy shows the current price and your local currency at checkout.
Related guides
How to size a cable to IEC 60364: a worked example with derating and voltage drop
Work out the design current Ib and choose the next standard breaker In. Divide In by the product of the ambient, grouping and soil correction factors to get the rating the cable needs. Pick the smallest size with that rating, check the voltage drop, keep the larger of the two sizes, and confirm Ib ≤ In ≤ Iz.
How to size an off-grid solar system: panels, battery and inverter
Add up each appliance's daily watt-hours and divide by inverter efficiency. Divide that by worst-month peak sun hours times a loss factor (0.780 in our example), plus a 10% margin, to get array watts. Battery capacity is daily energy times days of autonomy divided by depth of discharge. Then check cold-weather string Voc and inverter surge.
Questions
- Is this BS 7671 / AS/NZS 3008?
No. It follows the IEC 60364-5-52 sizing method, with current ratings calculated by the IEC 60287 thermal method (generic cable dimensions). National tables differ: use it for estimates, check against your own rules, or type your table's rating into the "Your table" columns.
- Where do I get peak sun hours?
Free tools such as PVGIS (EU JRC) or NASA POWER. Use the worst month for an off-grid system.
- NEC 220 load calculation?
No. This is an IEC-style board schedule (L1/L2/L3, kW and demand factors), not the NEC 220 dwelling method.
- Are these real exam questions?
No. All 21 problems are original, written in the style of the exam.