# Re: Official air breakdown voltage?

```Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Jason,

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There is a "very official" way. Up until recently, high voltages were "officially" measured with ball sparks gaps since that is all that worked scientifically and repeatably. A pretty official chart is here:
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http://hot-streamer.com/TeslaCoils/Misc/SGapVolt.jpg

3MV/Meter is also almost a "standard" value...

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Problem is, voltage fields stretch, bend, and distort.... So given a particular situation, figuring out the breakdown voltage can get super messy!!! There are fancy computer programs that can do it pretty well but it takes like an EE degree to run them... Some Ph.D folks can do it on paper... The functions are NOT straight lines at lower (~10kV) voltages either....
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But all that is for "DC"...... With "AC", we can cut arc channels through the air and spoil all the those rules anyway. It still can be figures out buy some high voltage AC gurus, but it is getting to the technical nightmare level at that point. Over the decades, Tesla coilers have made "rules" based on observations like John Freau's formula that get "us" through without too much brain damage.
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So for DC, the chart above does well.... (It works OK for 60Hz stuff too) There are some "rules of thumb" out there.... Beyond that, there are very messy methods only a few can figure out. Beyond that, the answer is pretty close to NO....
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Cheers,

Terry

At 12:51 PM 11/25/2005, you wrote:

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```I have read all over the net, around 25KV/inch  <<I use this one
I read on one place,           around 30KV/inch
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Now i have just been told around 30KV / cm !!!! Thats 3 times the voltage I have been told
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It is common sense that air pressure, humididty, current, and time of day all affect air breakdown voltage, but:
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IS there any official way to determine exactly what air breakdown voltage is? ( such as KV/distance )
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