Hi Terry, > I "think" the high energy explosive nature of the arc when the gaps are > shorting the primary circuit helps to blow them out, unlike when they are > just running the 60mA from the neon. - Thank you for this important clarification. I've learnt to distinguish: 1. A kickback from the tank circuit will blow out the safety gaps. 2. A short with e.g. a screwdriver (well insulated of course!) will result in permanent arcing. ok? Herwig