UES 5% specification
Keep voltage drop within 5% from the origin of the run. A 10% figure is shown only as an outer code limit. Anything above 5% is out of spec for UES designs.
Installer tools
Check copper cable size and voltage drop before you pull cable. UES specifies a maximum of 5% drop, even where a 10% outer limit is sometimes cited.
Quick terms: PF — how effectively current does useful work Current capacity — safe amps for the cable MCB — breaker / overload protection
Tap a row to select that size. Green is within the 5% UES spec and reference CCC. Amber is over 5% but within 10%. Red exceeds 10%.
| Size | Ref. capacity | Volt drop | % | Current | UES spec |
|---|
Runs added from this session. Print the page to keep a copy with the job file.
| Circuit | Supply | Cable | Distance | Load | Design I | Drop | Status |
|---|
Same method as the UES volt drop spreadsheet. Copper conductor resistance at 70 °C, design current with a 1.1 factor and 0.95 power factor, then drop as a percentage of 230 V.
Keep voltage drop within 5% from the origin of the run. A 10% figure is shown only as an outer code limit. Anything above 5% is out of spec for UES designs.
Three-phase drop uses I × R × L on each line, matching the spreadsheet. Single-phase uses 2 × I × R × L for the live-and-neutral loop.
Reference CCC values follow Voltex PVC general-purpose house wire ratings (two touching cables in a duct, 30 °C ambient, 70 °C conductor). 240 and 300 mm2 use multicore PVC free-air ratings from the same catalogue. Actual rating depends on installation method, grouping, and ambient temperature — confirm in SANS 10142-1 for the job.
This tool is an estimate / guidance aid only (not 100% accurate for every installation). It does not replace a competent person design, DC string calculations, or municipal submission documents. Need sign-off? Contact UES. Use is subject to our Terms & Disclaimer.