What is best practice/recommendation when I want to protect against lighting/surge? More specfically, my application requires passing the following test:

"ANSI/IEEE C62.41---1.2/50 microsecond (uS) — 8/20 uS Combination Wave. Peak voltage is 10kV, peak current is 5kA"

In the past I have had alot of sucess with just using MOVs alone, however, now I am thinking of using a TVS as well as spark gap right at the input for for extra protection on my next board. Here is the schematic for what I am talking about:

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    \$\begingroup\$ For reference, here is information for real-world protection units, meeting sets of safety regulation specification, as used in industrial plant settings, says, sensors and remote control wiring running hundreds meters on outdoor paths, subject to lightning strike. electronics.stackexchange.com/questions/124793/… \$\endgroup\$
    – EEd
    Commented Aug 13, 2014 at 19:48

1 Answer 1


I personally would not parallel TVS and MOVs. If you look at the voltage/current curves for similar voltage protection devices, typically you will find that the TVS will take all of the current as the MOV has a soft "knee" (voltage across MOV has to go quite high before an appreciable current is drawn).

I have seen MOVs used with spark gaps in several designs. To the best of my knowledge, spark gap devices will take a very high current, which is why they are used for lightning protection, but have an imprecise "flash over" voltage which can also change after a few sparks.


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