Download the calculation.
Calculate, review the result, then choose Download PDF. The watermarked record includes your inputs, results and method. PDF generation needs an internet connection.
How Smythy works
Change an input.
See what changes.
Start with two small examples. Change a cable run or a power factor, follow the result, then carry those inputs into the full calculator.
Try the voltage-drop example01 / Voltage drop
Extend the run.
Check the drop.
Keep the load at 20 A and make the run longer. Then try a larger conductor at the same length. Watch how each change affects the voltage lost before the supply reaches the shed.
Continue with your inputs to enter a different current, choose single or three phase, or find a conductor size for a chosen voltage-drop limit.
WORKED EXAMPLE / VOLTAGE DROP230 V · SINGLE PHASE
Voltage drop
6.732 Vlost along the run
At the board 230 VAt the shed 223.27 V
Fixed load 20 A
Table C8 simplified method. This demo checks voltage drop only, not cable capacity or installation compliance.
Continue with these inputs02 / Power factor
The same real power.
A different supply load.
A 10 kW load doesn’t always mean 10 kVA. Reduce the power factor and the apparent power rises, even though the real power stays the same.
The triangle shows the relationship between real, reactive and apparent power. Use the equipment’s rated or measured power factor when you move to your own calculation.
Try it / kW to kVA
As power factor falls, apparent power rises.
10kW0.80power factor
0.501.00
Illustrative sinusoidal AC load. Real power stays at 10 kW; S = P ÷ power factor.
Continue with this power factor03 / Full calculations
Go from an example
to the job details.
Maximum demandRecorded walkthrough
Choose Table C1, C2 or C3, then review how the entered loads contribute to demand. Check that the selected method applies to the installation.
Open maximum demand04 / Keep the working
Keep a record
of the calculation.
Return to a recent run.
The calculator library lists recent calculations on this device. Reopen one to review or change the inputs. Keep a PDF for work you need to retain; clearing browser data removes local records.
Check the result in context.
Read the tool’s assumptions and limits alongside the installation details. The PDF records the calculation; it does not certify an installation.