Flashover Voltage Calculator
Calculate the voltage at which electrical insulation fails and an electric arc jumps across a gap.
Voltage Calculator
Distance between electrical conductors
Material between conductors
Affects breakdown strength
Results
Enter gap distance and click "Calculate Voltage" to see results
What Is Flashover Voltage?
Flashover voltage is the point where electricity stops following its intended path and jumps through air or insulation instead. This usually happens when voltage becomes too high for the gap to safely contain it.
Think of it like a spark jumping across a gap in a spark plug. The electricity takes a shortcut through the air when the voltage gets high enough to ionize the air molecules, creating a conductive plasma channel.
Why Flashover Matters
Understanding flashover voltage is crucial because it explains the limits of electrical insulation and safety. It helps engineers design safer equipment, helps electricians work more safely, and helps students understand why high-voltage lines need to be spaced apart.
Flashover can cause equipment damage, create safety hazards, and explain why certain voltage levels require specific clearance distances. Knowing the flashover voltage helps prevent dangerous electrical failures.
Typical Air Gap vs Flashover Voltage
Here's how gap distance relates to flashover voltage in standard air conditions:
| Gap Distance | Approx Flashover Voltage |
|---|---|
| 1 mm | ~3 kV |
| 5 mm | ~15 kV |
| 10 mm | ~30 kV |
| 20 mm | ~60 kV |
Real-Life Examples
Flashover calculations apply to many electrical situations:
| Scenario | Gap | Flashover Result |
|---|---|---|
| Lab experiment | 5 mm | Near 15 kV |
| High-voltage line | 20 mm | Near 60 kV |
| Switchgear | 10 mm | Near 30 kV |
How the Calculator Works
The Basic Logic
Flashover Voltage = Breakdown Strength × Gap Distance
The calculator uses a standard voltage-per-distance value (typically 3 kV per mm for air) and multiplies it by your gap distance to estimate the flashover voltage.
This helps you understand the "why" behind electrical clearances and insulation requirements. The result shows the voltage level where the insulation would fail and an arc would jump across the gap.
Where Flashover Calculations Are Useful
Electrical design: Engineers use flashover calculations to determine safe insulation spacing and clearance distances in equipment design.
Education: Students learn the fundamental relationship between voltage, distance, and electrical breakdown through hands-on calculations.
Safety checks: Electricians and safety officers can verify that equipment meets voltage rating requirements for its physical spacing.
Experiments: Researchers and hobbyists can predict voltage limits for their electrical experiments and demonstrations.
What Makes This Calculator Different
Unlike technical engineering tools that assume advanced knowledge, this calculator is built for everyone—from students learning electrical basics to professionals making quick estimates.
It focuses on understanding rather than just numbers, with clear explanations of what flashover means and why it matters. The simple interface makes complex electrical physics accessible to anyone curious about how electricity behaves.
Safety is built-in with conservative estimates and clear warnings about the dangers of electrical flashover. This isn't just a calculation tool—it's an educational resource for safer electrical practices.