Protect gardeners near pumps, lights, and powered tools. Enter assumptions, then review pass or fail. Download results to support safer maintenance and planning today.
| Scenario | If (A) | Rtouch (ohm) | ρs (ohm·m) | Cs | t (s) | Vtouch (V) | Permissible (V) | Status |
|---|---|---|---|---|---|---|---|---|
| Garden pump housing, damp soil | 8 | 6 | 1500 | 1.00 | 0.3 | 48 | ~411 | PASS |
| Light post fault, long clearing time | 20 | 10 | 2000 | 1.00 | 3.0 | 200 | ~189 | FAIL |
| Metal fence energization, gravel layer | 15 | 4 | 3000 | 0.70 | 0.5 | 60 | ~426 | PASS |
This calculator estimates actual touch voltage using either Vtouch = If × Rtouch or a direct entered value. It then compares that value with a screening permissible touch voltage:
Eperm = (1000 + 1.5 × ρs × Cs) × (k / √t)
Outdoor garden equipment often mixes water, metal, and electricity. A damaged pump lead or light fitting can energize accessible surfaces. Touch voltage is the driving factor for current through a person. This calculator screens whether expected touch voltage stays below a permissible limit derived from soil conditions and clearing time. Use it to prioritize inspections and protective upgrades before routine gardening tasks for shared outdoor circuits.
Soil resistivity represents how easily fault current spreads into ground. Damp loam, irrigated beds, and shaded areas usually have lower resistivity than dry sand. When you cannot measure, choose a conservative higher value and document the assumption. The surface derating factor reflects insulating layers such as gravel, pavers, or rubber mats that reduce contact. Avoid unrealistic Cs values; use site conditions for future review and audits.
Shock duration is linked to how quickly protection clears a fault. Faster clearing reduces permissible exposure limits less severely and improves safety margin. Estimate duration from device type, trip settings, and likely fault magnitude. For unknown systems, use longer times to be conservative. If you improve bonding or add RCD protection, update duration assumptions and rerun the screening to confirm margin gains to see quantified improvement.
A PASS outcome suggests the modeled touch voltage is within the screening limit, but it does not certify compliance. Review utilization percentage and margin to judge robustness. A FAIL indicates elevated risk; reduce touch voltage by lowering resistance in the fault path, improving earthing, or limiting accessible conductive parts. Reduce exposure time with fast protection and maintain dry work practices around energized equipment, especially during wet seasons.
Good records support safe maintenance and informed decisions. Save CSV or PDF outputs with a short site note, photo references, and the equipment tag number. Log the assumed soil condition, surface layer, and clearing time. Recalculate after repairs, seasonal moisture changes, or equipment relocation. Over time, comparisons highlight weak zones, guide grounding improvements, and justify upgrades to protective devices for contractors and household safety briefings.
1) What does PASS actually mean here?
PASS means your entered touch voltage is below the screening permissible value for the chosen soil, surface factor, and duration. It reduces concern but does not replace detailed grounding design or code compliance checks.
2) Should I always use the 50 kg basis?
The 50 kg basis is more conservative and is often used for public-access areas. Use 70 kg when screening typical adult exposure. When unsure, select 50 kg and document why.
3) How can I estimate soil resistivity without testing?
Use typical ranges from local experience: wet clay is lower, dry sandy soil is higher. Choose a higher value if uncertain, especially during dry seasons, and treat results as a cautious screen.
4) What is a practical way to reduce touch voltage?
Improve earthing and bonding, repair damaged insulation, and reduce fault path resistance. Adding RCD/GFCI protection can also reduce exposure time, improving margins when a fault occurs.
5) Why does duration affect the permissible limit?
Longer exposure increases the chance of harmful current through the body. Faster clearing times generally allow higher permissible touch voltage. Use realistic clearing assumptions from protective devices.
6) Can I use this for solar garden lighting or pumps?
Yes, as a screening tool for any accessible outdoor electrical equipment. Enter realistic assumptions for contact and clearing time. For permanent installations, follow local electrical codes and qualified design guidance.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.